DEPABTMENT OF THE IHTERIOE

BULLETIN

OF THE

UNITED STATES

GEOLOGICAL SUKVEY

No. 148

WASHINGTON'

G-OVEKNMENT PRINTING OFFICE

1897

UNITED STATES GEOLOGICAL SUEYEY

CHARLES D. WALCOTT, 'DIRECTOR

ANALYSES OF ROCKS

ANALYTICAL METHODS

LABORATORY OF THE UNITED STATES GEOLOGICAL SURVEY

1880 to 1896

BY

F. W. CLAEKE AND W. F. HILLEBEAND

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1897

CONTENTS.

Pago.

Introduction, by F. W. Clarke ....'.......................................... 9

Some principles and methods of analysis applied to silicate rocks; by W. F.

Hillebrand................................................................ 15

Part I. Introduction ................................................... 15

Scope of the present paper .......................................... 20

Part II. Discussion of methods ..................................i....... 22

Preparation of sample....................:.......................... 22

Specific gravity. ............................: ......--.........--... 23

Weights of sample to be employed for analysis....................... 26

Water, hygroscopic ................................ ................. 26

Water, total or combined....... ^.................................... 30

Silica, alumina, iron, etc............................................ 34

Manganese, nickel, cobalt, copper, zinc.............................. 41

Calcium and strontium...................................... ........ 43

Magnesium......................................................... 43

Barium and titanium............... .... ............................. 45

Zirconi uni.......................................................... 48

Rare earths other than zirconia ............................... ...'... 50

Chromium and phosphorus .......................................... 51'

Ferrous iron ........................................................ 52

Alkalies ............................................................ .54

Carbon dioxide...................................................... 56

Chlorine............................................................ 57

Fluorine............................................................. 57

Sulphur ............................................................ 58

Boron .............................................................. 59

Nitrogen............................................................ 59

Special operations. .............................................. .... 60

Estimation of minute traces of certain constituents .................. 61

Preliminary qualitative analysis ....... i....... 1.................... 62

Summation of analytical results..................................... 62

Quality of reagents .................................................. 63

Analyses of rocks; arranged and tabulated by F. W. Clarke.................. 65

Igneous and crystalline rocks ........................................... 65

Maine .............................................................. 65

New Hampshire......^.............................................. 67

Vermont............................................................ 68

1. Rocks of Mount Ascutney..................................... 68

2. Miscellaneous rocks .......................................... 71

Massachusetts ...................................................... 72

1. Rocks of the Connecticut Valley.............................. 72

2. Miscellaneous rocks ......i................................... 77

5
6 CONTENTS.

 Analyses of rocks; arranged and tabulated by F. W. Clarke Continued. Page. 

Igneous and crystalline rocks Continued.

Connecticut........ v................................................. 79

New York .......................................................... 79

New Jersey......................................................... 80

Pennsylvania....................................................... 81

Delaware........................................................... 82

Maryland and the District of Columbia.............................. 83

1. Peridotite and pyroxenite .................................... 83

2. Gabbro and diorite ........................................... 85

3. Granite and gneiss ........................................... 85

4. Miscellaneous rocks .......................................... 90

Virginia............................................................ 91

North Carolina.................. .................................... 91

1. Rocks from Corundum Hill................................... 91

2. Pyroxenite from Webster..................................... 92

Kentucky............................................................ 92

1. TheElliott County dike ...................................... 92

2. The Crittenden County dike.......".........,.................. 94

Missouri............................................................ 95

Arkansas ........................................................... 96

Texas............................................................... 96

The Lake Superior Region .......................................... 97

1. The Marquette and Michigamme Region, Michigan............ 97

2. The Menominee River ........................................ 100

First. The Sturgeon Falls gabbro............................ 100

Second. Lower Quinnesec Falls .............................. 101

Third. Upper Quinnesec Falls ............................... 102

3. The Penokee-Gogebic Region ................................. 103

4. Rocks of Pigeon Point, Minnesota ............................ 104

5. Miscellaneous rocks from Minnesota ........................... Ill

South Dakota....................................................... 114

Wyoming............................. ...... ........................ 115

The Yellowstone National Park.. .................................... 117

1. Electric Peak ...........'.....................-........-...--. 117

2. Sepulcher Mountain .......................................... 120

3. The Crandall Basin........................................... 122

4. Absarokite-Shoshomte-Banakite series .......... .............. 125

5. Miscellaneous rocks .......................................... 130

Montana .........^..................^............................... 137

1. The Madison and Gallatin valleys ............................ 137

2. The Crazy Mountains......................................... 142

3. The Little Belt Mountains .................................... 146

4. The Castle Mountain district...........................'...-.. 150

5. The Highwood Mountains .................................... 152

6. The Little Rocky Mountains................--.--....-....---- 155

7. The Bearpaw Mountains..............................-------- 156

Colorado ........................................................... 158

1. The Denver Basin ............................................ 158

2. The Pikes Peak district ...... ....:..........-.....--.-----.-- 159

3. Silver Cliff and Rosita........................................ 165

4. The Buffalo Peaks.... ........................................ 171

5. The Leadville region ......................................... 172

6. The Ten Mile district......................................... 175

7. The Elk Mountains........................................... 177
CONTENTS. 7

Analyses of rocks; arranged and tabulated by F. W. Clarke Continued. Pago. 

Igneous and crystalline rocks Continued. 

Colorado Continued.

8. The AVest Elk Mountains..................................... 178

9. Miscellaneous rocks .......................................... 179

Utah ............................................................... 183

New Mexico ........................................................ 184

1. Basalts from Eio Graude Canyon.............................. 184

2. The Mount Taylor region..................................... 185

3. Miscellaneous ................................................ 186

Arizona............................................................. 187

Nevada.........................................:................... 188

1. Eocks from Washoe .......................................... 188

2. Rocks from Eureka........................................... 189

California ...............................--.-.-..--.....:............ 190

1. Mount Shasta ...........1................-..-.-.-..-.-....-. 190

2. The Lassen Peak region ..................................... 191

First. Ehyolites ........................................... 192

Second. Dacites and audesites.............................. 193

Third. Basalts ................ ..f .......................... 198

3. Plumas County................................,,............. 201

4. ButteCounty ............................................... . 204

5. Sierra County................................................ 206

6. Nevada City and Grass Valley ............................... 208

7. Placer County.....;......................................... 211

8. Eldorado County............................................ 213

9. 'Araador County ............................................. 214

10. Calaveras County ...............:........................... 216

11. Tuolurnne County........................................... 217

12. Mariposa County............................................ 219

13. The Quicksilver region ...................................... 222

14. Mount Diablo ............................................... 224

15. Miscellaneous rocks ......................................... 228

Oregon ..........i................................................... 230

1. Basalt, Mount Thielson.......................°................ 230

2. Peridotite from Douglas County .............................. 231

3. Basalt, near Crater Lake ..................................... 231

Alaska.............................................................. 232

Stony meteorites........................................................ 234

Meteoric iron ........................................................... 244

Sandstones and cherts................................................... 247

Ohio................................................................ 247

California .......................................................... 248

1. Mount Diablo ................................................ 248

2. Shasta County................................................ 249

3. Sulphur Bank................ ................................ 250

Miscellaneous sandstones............................................. 251

Chert............................................................... 252

The carbonate rocks..................................................... 254

Vermont and Massachusetts......................................... 254

New York, Pennsylvania, Maryland ................................. 255

Virginia and West Virginia ......................................... 256

Georgia............................................................. 257

Tennessee, Alabama, Louisiana...................................... 258

Florida................. ............................................ 259
8 CONTENTS.

Analyses of rocks; arranged and tabulated by F. W. Clarke Continued. Page. 

The carbonate rocks Continued.

Ohio................................................................ 260

Indiana............................................................. 263

Missouri ...................... ...................................... 264

Kansas.........................-................_...............__,_. 264

Michigan, Wisconsin, Minnesota, Canada............................. 265

Montana............................................................ 269

Colorado............................................................ 270

1. The Denver Basin ............................................ 270

2. The Leadville district...... .................................. 271

3. Fairplay, Park County ...................,................... 272

4. Pitkin County ............................................... 272

5. Glenwood Springs............................................ 273

6. Ten Mile district.............................................. 274

Utah ............................:.......,.......................... 275

Nevada and California.............................................. 275

Hawaiian Islands................................................... 276

Slates and shales..,.........................."..............'............. 277

Vermont............ ................................................ ' 277

New York. *........................................................ 280

Kentucky, Georgia, Alabama........................................ 282

Ohio................................................................ 283

Wisconsin .......................................................... 283

Colorado............................................................ 284

California .......................................................... 285

Clays, soils, etc.......................................................... 287

Massachusetts ............;........ ^................................. 287

New York, Pennsylvania, Delaware.................................. 288

Virginia, North Carolina ..................I......................... 289

South Carolina, Georgia............................................. 290

Florida............................................................. 290

Alabama, Mississippi............................ .............. ...... 292

Illinois, Iowa, Minnesota............................................ 293

Wisconsin........................................................... 294

Missouri, Arkansas.................................................. 295

Colorado ........................................................... 297

Wyoming, Utah, New Mexico........................................ 299

Nevada............................................................. 300

California, Washington, Hawaiian Islands........................... 301

Index to rocks .............................................................. 303
ANALYSES OF ROCKS, WITH A CHAPTER ON ANALYTICAL 

METHODS, LABORATORY OF THE UNITED STATES GEOLOGICAL SURVEY, 1880-1896.

By F. W. CLARKE and W. F. HILLEBRAND.

By F. W. CLARKE.

The present Geological Survey of the United States was organized 

in 1879. In 1880"a chemical laboratory was established at Denver, in 

connection with the Colorado work, in charge of Dr. W. F. Hillebrand, 

with whom were associated Mr. Antony Guyard and, later, Mr. L. G. 

Eakins. In 1882 Dr. W. H. Melville was placed in charge of a second 

laboratory at San Francisco, and in the autumn,of 1883 the central 

laboratory was started in Washington,, with myself as chief chemist. 

In November, 1885, Dr. Hillebrand was transferred to Washington; he 

was followed early in 1888 by Mr. Eakins, and the Denver laboratory 

was discontinued. Dr. Melville was also brought to Washington in 

the spring of 1890, and since then the chemical work of the Survey has 

been concentrated at headquarters.

Up to January 1,1897, about 3,700 analyses have been made in the 

laboratory at Washington. These represent rocks, minerals, ores, 

waters, sediments, coals, metals, and so on through all the range of 

substances with which geology has to do. There were also some hundreds of analyses made in the laboratories at Denver and San Francisco, 

and a fair amount of research work upon mineralogical and analytical 

problems has also been done. In all of this work the following chemists have been employed: Charles Catlett, T. M. Chatard, F. W. Clarke, 

L. G. Eakins, F. A. Gooch, Antony Guyard, W. F. Hillebrand, W. H. 

Melville, B. B. Riggs, E. A. Schueider, George Steiger, H. N". Stokes,

9
10 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

and J. E. Wkitfteld. As many as eight of these have been at work 

simultaneously; at present only four are connected with the Survey. 

Other officers of the Survey have been occupied more or less with chemical questions; but the men named in this list were connected directly 

with the laboratory. Some work for the chemical division has also 

been done by chemists not regularly on the rolls of the Survey; but 

their analyses, with a single exception to be noted later, do not fall 

within the scope of this paper. '

Quite naturally, on account of the activity of the petrographers, the 

dominant feature of the laboratory work has been the analysis of rocks. 

These have been studied in great numbers, and in the most thorough 

way. The results have appeared in widely scattered publications, official reports, monographs, bulletins, American and foreign journals, and 

so on. The object of this bulletin is to bring together this valuable 

material, together with such bibliographic and petrographic data as 

seems to be necessary in order to identify the specimens and to facilitate chemical discussion. » Analyses of minerals have been included 

only when related to petrographic studies, appearing then in connection with the rocks to which they belong. Meteorites, of which twentyseven have been analyzed, are brought into the work on account of 

their petrographic relations; and the groups of clays and soils have been 

admitted because of the bearing of these substances upon the study of 

slates and shales. The actual number of analyses given in the bulletin 

is as follows:

Igneous and crystalline rocks ............................................... 692

Mineral separations......................................................... 78

Meteorites, and separations from them.....:................................. 58

Sandstones and cherts....................................................... 36

Carbonate rocks ............................................................ 183

Slates and shales............................................................ 45

Clays, soils, etc............................................................. 93

Total................................................................. 1,185

It may be observed that the classification thus indicated has not been 

rigorously followed. In a few instances the study of a sedimentary 

rock has been so related to that of its igneous neighbors that the analyses 

are best tabulated together; but these exceptional cases are few, and all 

are properly noted. The heading of "igneous and crystalline rocks" 

has been used in the broadest and most liberal way, and doubtless 

many of the analyses given under it might properly be otherwise classified. In such cases of uncertainty, convenience has furnished the 

rule to follow.

Within each division of the analyses the classification chosen has 

been geographic. The petrographic grouping of the rocks would doubtless be best, were petrographers agreed upon it; but their differences 

are many, and the chemist will do well to avoid them. The geographic 

method, moreover, has some advantages of its own; it facilitates the
HILLEBHAND.J CLARKE AND! TTSTTTfnDTTPTTON 1 1 1JN 1 KUJJ U ly 11UJN . J. 1

study of areas, it simplifies the bibliographic references, and it brings 

together in great measure the work of each petrographer for whom 

analyses have been made. Thus, most of JDiller's work has been in 

California, most of Cross's in Colorado, and most of Iddings's in the 

Yellowstone National Park; and in each case the analyses are massed 

and their discussion is practically uniform in character. As regards 

nomenclature, each rock has received the designation given it by its 

describer, and no liberties have been taken. This plan may cause some 

lack of uniformity; but no other procedure seemed to be practicable.

It will be noticed by anyone who uses this bulletin that the analyses 

vary as regards completeness. Among the sedimentary rocks, especially, partial analyses are common; but in the igneous group thoroughness is more general. In the early days of the chemical division many 

analyses were made along the older lines, just as they are still made in 

many laboratories to-day that is, only the main constituents, those

having direct petrographic significance, were determined. In such 

analyses the minor ingredients, like titanium, phosphorus, barium, 

strontium, chlorine, etc., were ignored; and, although the results are 

satisfactory in some respects, they leave much to be desired. Latterly, 

greater completeness has been, sought for, the work done has been 

much fuller, and the data obtained can be discussed with much higher 

approaches to accuracy. The old form of " complete analysis " is to be 

discouraged; it leads too often to erroneous conclusions; and only the 

best modern methods of work and of statement should be tolerated. 

The fuller analyses, moreover, have brought some interesting points to 

light; titanium now appears to be one of the more abundant elements., 

and barium and strontium are found to be almost universally diffused 

in igneous rocks in quite perceptible quantities.

On general principles the analysis of a rock and its petrographic 

description should be two parts of the same investigation, matching 

each other completely. In practice, however, this rule does not always 

hold, and the departures from it a.re in two opposite directions. For 

example, an analysis of the older type says nothing of titanium and 

phosphorus, while the microscope reveals the presence of sphene and 

apatite. In this case the petrographer has been more thorough than 

the chemist. On the other hand, a full and perfect analysis may be 

given, accompanied by a petrographic description of the most general 

kind, in which only the main mineral constituents "of the rock are 

noted. Here the analysis has been incompletely used, and the petrographic discussion is defective. It is hoped that the publication of 

this material may lead to a clearer recognition of the mutuality which 

should exist between the chemical and the microscopic researches, and 

so bring, in the future, both lines of investigation more into harmony. 

Hitherto the chemist and the petrographer have worked too much 

apart, and each has too often misunderstood the purpose of the other. 

If the study of the thin section could always precede the analysis, the
12 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

petrographic problems could be stated more clearly, and the chemical 

evidence might be rendered much more pertinent and satisfactory.

In a paper published some years ago, 1 on the relative abundance of 

the chemical elements,.! computed the average composition of the 

primitive crust of the earth from 880 analyses of eruptive and crystalline rocks. Of these analyses only 207 were from the laboratories of the 

Survey, while 673 were collected from various other American and foreign sources. A large proportion of them were incomplete, regarded 

from a modern point of view, and yet the results obtained were fairly 

conclusive. The material now available for similar discussion is much 

better than that which was formerly used, and an average based upon 

it may not be out of place here.

In the bulletin now presented I have fourid 680 complete analyses of 

rocks which are suitable for my purpose. I have also taken from the 

partial analyses given in the laboratory records 180 additional determinations of silica, 90of lime, and 130 of alkalies. In 340 of theanalyses 

there is discrimination between the water lost below 110° and that 

which is essential to the composition of the rocks; and this amounts to 

0.40 per cent. Omitting this water, the average found may fairly represent the composition of the older crust of the earth, as deduced 

from a mass of data which are reasonably uniform in character and 

entitled to a high degree of credence. The mean for the more important constituents is as follows, with the old average given in a parallel 

column for comparison:

SiOa.. ....................

AOaOs.. ...................

Fes08 ....................

FeO--..-... ..............

CaO .....................

MgO. ....................

K2O. .....................

NfbO.... .................

H2O.. ....................

Ti02 .....................

PaOB . .....................

New mean.

59.77

15.38

2.65

3.44

4.81

4.40

2.83

3.61

1.51

.53

.21

99.14

Old mean.

58.59

15.04

3.94

3.48

. 5. 29

4.49

2.90

3.20

a 1.96

.55

.22

99.66

a Including hygroscopic water.

i Bull. TJ. S. Geol. Survey No. 78,1891, p. 34.
CLAKKE AND"! 

H1LLEUBAND.J INTRODUCTION. 13

If we reduce these figures to elementary form and include minor constituents, the two averages compare as follows:

Oxygen ..................

Silicon ...................

Potassium ................

Sodium ..................

Titanium .................

Hydrogen ................

Carbon ............. '. .....

O

Nickel ...................

Lithium ..................

New mean'.

47.13

 27.89

8.13

4.71

3.53

2.64

2.35

2.68

.32

.17

.13

.09

.07

.06

.04

.01

.01

.01

.01

.01

.01

100. 00

Old nioaii.

47. 29

27.21

7.81

5.46

3.77

2.68

2.40

2.36

.33

.21

.22

.10

.08

.03

.03

.01

.01

100. 00

As the old mean represents an attempt to measure the composition, 

of the entire solid crust of the earth, and so includes an allowance for 

the carbon in the limestones, the two columns are not strictly comparable. They are, however, corroborative of each gther, and show that 

within reasonable limits the statistical method is applicable to the 

problem under consideration. For the arguments upon which the discussion is based the original paper should be consulted. For the 

elements not in the table no estimates can now be made; but not one, 

probably, could reach 0.01 per cent in quantity. Their proportions 

may be regarded as small corrections to be applied at some time in the 

future.

During the preparation of this bulletin much assistance was rendered 

by the petrographers and geologists connected with the Survey, especially with reference to analyses hitherto unpublished. In each case 

credit has been given for the data thus added. Twenty-eight analyses 

of rocks from Montana, executed by or under the direction of Prof. 

L. Y. Pirsson, of Yale University, and having been made in connection 

with regular Survey work, are included in the tabulations. With this
14 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

exception all of the analyses given were made in the Survey laboratories. To those executed in the laboratory at Washington "record 

numbers" are attached, which serve to identify them on the record 

books of the Division of Chemistry. Of the abbreviations used for 

bibliographic reference only three need explanation, and they refer to 

the official publications of the Survey. "Ann." for Annual Keport, 

"Mon." for Monograph, and "Bull." for Bulletin are the three in question. The others relate to well-known journals, and are familiar to all 

geologists.
SOME PRINCIPLES AND METHODS OF ANALYSIS APPLIED TO

SILICATE ROCKS.

By W. F. HlLLBBRAND.

PART I. INTRODUCTION.

The composition of the ultimate ingredients of the earth's crust the 

different mineral species which are there found and of many of which 

its rocks are made up was the favorite theme of the great workers in 

chemistry of the earlier half of this century, and for the painstaking 

care and accuracy of Berzeliusf Wohler, and others the mineralogists 

and geologists of to-day have need to be thankful. Considering the 

limited facilities at their disposal in the way of laboratory equipment 

and quality of reagents, the general excellence of their work is little 

short of marvelous. As an outgrowth of and closely associated with the 

analysis of minerals came that of the more or less complex mixtures of 

them the rocks to aid whose study by the petrographer and geologist 

a host of chemists have for many decades annually turned out hundreds of analyses of all grades of quality and completeness. With the 

growth and extraordinary development of the so-called organic chemistry inorganic chemistry gradually fell into a sort of disfavor. In 

many, even of the best, European laboratories the course in mineral 

analysis, while maintained as a part of the curriculum of study, became 

but a subordinate prelude to the ever-expanding study of the carbon 

compounds, whose rapid multiplication, offering an easy and convenient 

field for original research and possible profit, proved a more tempting 

opening to young chemists than the often-worked-over and apparently 

exhausted inorganic pasture. For one student devoting his time to 

higher research on inorganic lines were perhaps fifty engaged in erecting the present enormous structure of carbon chemistry. The instruction afforded the student in mineral analysis was confined to the 

ordinary separations of the commoner ingredients occurring in appreciable quantities, with little regard to supposed traces and with still less 

attempt to find out if the tabulated list really comprised all that the 

mineral or ro<jk contained.

With the introduction of improved methods of examination by the 

petrographer, especially as applied to thin rock sections and the use of 

heavy solutions, whereby, on the one hand, the qualitative mineral 

composition of a rock could be preliminarily ascertained with considerable certainty, and on the other, chemical examination of the more or 

less perfectly separated ingredients was rendered possible, a great help

15
16 ANALYSES OF EOCKS AND ANALYTICAL METHODS. [BULL. 148.

and incentive was afforded to the few chemists engaged in rock analysis. The microscope often obviated in part the necessity for tedious and 

time-wasting qualitative tests, and the heavy solutions, by permitting 

the concentration and separation of .certain components, facilitated the 

detection of elements whose existence had long been overlooked.

Meanwhile in the progress of chemistry new methods and reagents 

for qualitative detection and quantitative separation and estimation 

were gradually being discovered and devised. The supposed adequacy 

of some well-established methods was shown to be unwarranted; some 

had to be discarded altogether; others were still utilizable after modification. In the light thus shed it became possible to explain many 

hitherto incomprehensible variations in the composition of some rock 

species or types, as shown in earlier analyses, and in not a few cases it 

appeared that the failure to report the presence of one or more elements had obscured relations and differences which more thorough 

examination showed to exist (see pp. 17-18). Consequently there arose 

a feeling of distrust of much of the older work in the minds of those 

chemists and petrographers best qualified to judge of its probable 

qualities. This, and the incompleteness of nearly all the earlier work 

(and much of that of to-day unfortunately), as shown by the largely 

increased list of those elements now known to enter into the normal 

composition of rocks, is rendering the old material less and less available to meet the increasing demands of the petrographer.

And yet these demands on his part are, with few exceptions, by no 

means so exacting as they should be. Often the analysis is intrusted 

to the hands of a student without other experience than that gained, 

by the analysis of two or three artificial salts and as many comparatively simple natural minerals, and with a laboratory instructor as 

adviser whose experience in rock analysis may be little superior to his 

own. In other words, one of the most difficult tasks in practical analysis is expected to be solved by a tyro, and his results are complacently 

accepted and published broadcast without question, Even to those 

thoroughly familiar with the subject rock analysis is a complex and 

often trying problem. Although long practice may have enabled 

one to do certain parts of it almost mechanically, he is still from time 

to time confronted with perplexing questions which require trained 

judgment to properly meet and answer, and there is still room for important work in some of the supposedly simplest quantitative determinations. If the results are to be of any decided value for purposes 

of scientific interpretation and comparison, they should be the product 

of one competent to find his way through the intricacies of an analysis 

in which from fifteen to twenty-five different components are to be 

separated and estimated with, close approach to accuracy, and this a 

beginner can not hope to do in the majority of cases. The conscientious chemist should have a live interest in this matter. He should 

work with a twofold purpose in view that of lightening the labors of 

those who come after him by enabling them to use his work with less 

supplementary examination, and of thereby enhancing his own reputation by meriting encomiums on work that has stood the test of time.
CLARKE ANDT 

HILLEBRAND.J IMPORTANCE OF COMPLETE ANALYSES. 17

The petrographer, again, should seek to have his analyses made as 

complete as possible, and not, as is so often the case, be content with 

determinations of silica, alumina, the oxides of iron, lime, magnesia, 

the alkalies and water. The latter, it is true, are entirely justifiable 

at times, and may serve the immediate purpose for which they were 

intended, but their incompleteness may, on the other hand, not only 

conceal points fruitful of suggestion to the attentive mind, but, what is 

of still greater importance, they may be actually misleading. Enough 

instances of totally inaccurate conclusions to be drawn from them have 

fallen under my own observation to fully justify this plea in favor of 

greater completeness in rock and mineral analyses made for purely 

scientific purposes.

This is shown by the difference between the following analyses:

SiO».. ....................

Ti02 .....................

A1203 . ....................

Cr803 ....................

Fe.203 ....................

FeO.... ..................

MnO.... .................

CaO.... ..................

SrO. :.......'.............

BaO ............... .....

MgO. ....................

K2 0.... ..................

NmO. ....................

Li2O .....................

H2 0 below 110° C ........

H2 0 above 110° C.........

ri/-» OUj ..................... n

P20f) .....................

S03 ......................

F ........................

Cl. .......................

Less 0 for F..............

Earlier 

analysis.

54.42

13.37

".61

23.52

4. 38

6.37

10.73

1.60

«2.76

1.82

99.58

Later 

analysis. 1

53.70

1.92

11.16

.04

3.10

1.21

.04

3.46

.19

.62

6.44

11.16

1.67

Trace.

.80

2.61

1.75

.06

.44

.03

100. 40 

I'Q

100. 21

'A still more recent analysis of another of the series of rocks of which this is an example has shown 

that this "later analysis " is itself probably incomplete and incorrect in part incomplete because of 

the probable presence of .2 per cent or more of Zr02 , incorrect because of the error in A1203 resulting 

from having counted the Zr02 as A1203 , and from the fact that titanium is not fully precipitable in 

presence of zirconium by Gooch's method (the one employed). This latter error involves both the 

Ti02 and the A12 03 (see p. 48).

2 From the fact that repeated determinations of the iron oxides in this and related rocks from the 

same region show always a great preponderance of ferric oxide, it is not improbable that the figures 

given for the two oxides in the first analysis wore accidentally transposed.

8 In the published analysis it does not appear whether this is total water or, as seems probable, only 

that remaining above 100° C.

Bull. 148 2
18 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

The specimens were taken and analyzed at widely separated times and 

by different persons, it is true, but they were unquestionably from the 

same rock mass, in which, however much the relative proportions of 

the different mineral constituents might vary within certain limits, 

there can be no reason to doubt the general distribution of all the 

elements shown by the second analysis.

Another instance of similar kind is given below. Here, again, certain 

differences are explainable by natural variations in the proportions 

of the constituent minerals, but it can hardly be doubted that TiO2, 

BaO, SrO, P2O5 , and SO3 were- present in both specimens in approximately the same amounts. In the earlier analysis in this case determinations of some supposed unimportant constituents were purposely 

omitted or only made qualitatively, with results that can not be otherwise than fatal to a full comprehension of the mineralogical nature of 

the rock:

SiO2 . .....................

Ti02 .....................

A13O3 . ....................

FejOs .......... ..........

FeO. ....... ..............

MnO .....................

CaO.... ..................

SrO ......................

BaO......................

MgO. ....................

KsO.. ....................

NajO. ....................

Li,0. ....................

H3O below 110° C ........

H30 above 110° C ........

C09 .................. ....

PS06 ... . ..............

01...... ..................

SO3 ......................

Earlier 

analysis.

44.31

17.20

4.64

3.73

.io

10.40

6.57

3.64

4.45

.77

3.30

99.11

Later 

analysis.

44.65

.95

13.87

6.06

. 2.94

.17

9.57

!.37

.76

5.15

4.49

5.67

Trace.

.95

2.10

.11

1.50

.61

99.92

1 Not entirely free from CaO.

In order to more strongly emphasize the importance of completeness 

in analysis, one fact brought out by the hundreds of rock analyses made 

in this laboratory may be cited. It has been demonstrated most conclusively that barium and strontium are almost never-failing constituents
HILLEBRAND. IMPORTANCE OF COMPLETE ANALYSES. 19

of the igneous rocks and many of their derivatives of the United States. 

These amounts are usually below 0.1 per cent for each of the oxides of 

those metals, but higher amounts are by no means uncommon. Furthermore, the weight of barium is almost without exception in excess 

of that of strontium. But a still more important point is that the igneous rocks of the Rocky Mountain region, so far as examined, show far 

higher average percentages of both metals than the rocks from the 

eastern and the more western portions of the United States. The following examples serve to illustrate certain types of Eocky Mountain 

igneous rocks: Of seven rocks forming a Colorado series, six held from 

0.13 to 6.18 per cent of BaO, while in the seventh the percentage was 

0.43. The SrO ranged from 0.07 to 0.13 per cent for six, and was 0.28 

for that one highest in BaO. Of thirteen geologically related rocks 

from Montana, embracing basic as well as acid and intermediate types, 

the range of BaO was from 0.19 to 0.37 per cent, with an average of 

0.30 per cent. Three others of the same series contained 0.10 per cent 

or less, while the seventeenth carried 0.76 per cent BaO. The SrO 

ranged from 0.37 per cent in the last instance to an average of 0.06 for 

the other sixteen. Certain peculiar rocks from Wyoming carry from 

0.62 to 1.25 per cent BaO, and from 0.02 to 0.33 per cent SrO. Surely 

this concentration of certain chemical elements in certain geographic 

zones has a significance which future geologists will be able to interpret? 

if those of to-day are not.

While strongly upholding the necessity for more thorough work, 

necessarily somewhat at the expense of quantity, it is far from the 

writer's intention to demand that an amount of time altogether disproportionate to the immediate objects to be sought should be expended 

on every analysis. But it is maintained that in general the constituents which are likely to be present in sufficient amount to admit of 

determination in the weight of sample usually taken for analysis say 

1 gram for SiO2 , A12O3 , etc., to 2 grams for certain other constituents 

should be sought for, qualitatively at least, in the ordinary course of 

quantitative work, and their presence or absence noted among the 

results. If present in little more than traces, that knowledge alone 

may suffice, for it is often more important to know whether or not an 

element is present than to be able to say that it is there in amount of 

exactly 0.02 or 0.06 per cent. In the tabulation of analyses a special 

note should be made in case of intentional or accidental neglect to look 

for substances which it is known are likely to be present. Failure to do 

this may subject the analyst to unfavorable criticism, when at some 

future time his work is reviewed and the omissions are discovered by 

new analyses.

Finally, whenever possible, a thorough microscopical examination of 

the rock in thin section should precede the chemical analysis. This 

may be of the greatest aid to the chemist'in indicating the presence of
20 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

unusual constituents, or of more than customary .amounts of certain 

constituents, whereby, possibly, necessary modifications in the analytical procedure may be employed without waste of time or labor.1

SCOPE OF THE PRESENT PAPER.

The literature relating to analysis of silicates is extensive, but scattered; and the scheme given by Fresenius in his Quantitative Analysis answers well for the ordinary separations and is probably almost 

universally followed in all its essential features; but in no -single article, 

to the writer's knowledge, is .there to be found an exposition of the 

methods to be followed or the precautions to be observed in the search 

for some of the rarer constituents or those which, without being rare, 

have been of late years recognized as occurring persistently in small 

amounts. It is not the object of the writer to make this paper a treatise on mineral analysis; but it is believed that the experience gained 

by the chemists of this survey during the sixteen years since the establishment of its first chemical laboratory in Denver may be useful to 

most chemists interested in mineral and especially rock analysis. 

Lengthy descriptions of details of manipulation will be avoided so far 

as possible, and in general only an outline will be presented of the 

methods followed or recommended, since in the main they are familiar 

to all or easily accessible; but stress will be laid on those points meriting particular attention, and now and then .a brief discussion of alternative methods may be attempted.

In the 'earlier years of the existence of the Washington laboratory 

opportunity was afforded for the testing of novel methods and the 

devising of new ones, with most excellent results, as shown especially 

by the methods for separation of titanium, of lithium, and of boron, 

due to Prof. F. A. Gooch, to whose inventive skill chemists owe likewise the perforated filtering crucible and the tubulated platinum crucible arrangement for the estimation of water. Of late years the press 

of routine work has been such as to fully fill up the time of the muchreduced chemical force, and as a consequence it has been found impossible to subject to critical trial several separation methods of recent 

origin, some of which seem to be full of promise, or to follow out certain lines of investigation which have been suggested by the observations made in this laboratory, one, at least, of which seems to be of 

high importance. This, then, must be offered in explanation if, in the 

following discussion, it may seem to some that any of the methods followed are too conservative or not sufficiently up to date. In general 

the discussion will be confined strictly to such separations as may be 

required in the analysis of an igneous, metamorphic, or sedimentary

1 The foregoing tables and accompanying remarks, including several sentences preceding the tables, 

have been largely taken from the writer's paper entitled, " A plea for greater completeness in chemical rock analysis," published in the.Journal of 'the ^merican.Ckemlc.al.SQoiety, VoL.XVI, ;pp. 90-93 

1894;.also in the Chemical News, Vol. LXIX, p. 163,1894.
HILLEBBAND. SCOPE OP THE PRESENT PAPER. 21

silicate rock of complex mineralogical composition, in which the majority of and possibly all the ingredients in the list given below may 

occur in weighable or readily discoverable quantities:

Si02

NiO

MgO

so3 

TiO,

CoO'

K20

S*

ZrO,

CuO

Na.2 0

N,

A12O3

MnO

Li2O 

Fl

Cr2 03

CaO

H20 

Cl

Fe2 0:i

SfO

C02

FeO

BaO

Ct

The special problems often arising in the analysis of rocks of extraterrestrial origin the more or less stony meteorites will not be considered in this paper. An analysis of that kind should never be 

entrusted to the novice, but only to the chemist who has a knowledge 

of the composition and properties of the peculiar mineral constituents 

of those bodies, and a judgment fit to cope with the oftentimes difficult 

problems presented by them.

Thorium, cerium, and other rare earths are seldom encountered in 

quantities sufficient to warrant the expenditure of the time necessary 

for their isolation. A search for them qualitatively, even, is at present 

rarely justifiable unless there is microscopic or other evidence of the 

presence of minerals likely to contain them. Vanadium, tantalum, 

columbium, boron, and glucinum have never been certainly met with 

in the writer's experience, and yet they must be present in certain 

rocks, and doubtless traces have been overlooked at times. There is 

no reason to suppose that other elements may not be found by careful 

search, possibly all in the known category, and, indeed, Sandberger's 

researches have shown to what an extent this is true of a large number 

of those elements contributing to the filling of metalliferous veins. 

But those in the above list may usually be estimated with ease in 

weights of from one-half to 2 grams.

If the point be raised that many of the published analyses emanating 

from the Survey laboratories, even the earlier ones of the writer, are not 

in accord with the advocacy of completeness contained in. the foregoing, 

pages, it may be remarked that these ideas have been to a considerable 

degree evolved during a personal experience of sixteen years in this 

line of work, and that frequently the exigencies were such as to compel 

restriction in the examination. Where the latter has been the case 

subsequent developments have in some cases shown it to be bad policy 

in every respect. It is better, both for the geologist and the chemist, 

to turn out a limited amount of thorough work than a great deal of 

what may prove to be of more than doubtful utility in the end.

In this connection the question has often been put, "How long does 

it take to complete an analysis of this kind 1?" This will depend, of 

course, on the mineral complexity of the sample and on the personal 

factor of the individual worker. If there is a competent assistant to 

do the grinding, and specific-gravity determinations are not required,

* Usually as pyrite, not infrequently as pjTThotite. t As graphite or coaly matter.
22 ANALYSES OF-ROCKS AND ANALYTICAL METHODS. [BULL. 148.

it is quite possible after long experience for a quick worker to learn to 

so economize every moment of time in a working day of seven hours, 

with an abundance of platinum utensils and continuous use of air and 

water baths through the night, as to finish every three days, after the 

completion of the first analysis, barring accidents and delays, one of 

a series of rocks of generally similar character, each containing from 

eighteen to twenty quantitatively determiuable constituents, excluding, 

for instance, fluorine", carbon as such, nitrogen, metals of the hydrogen 

sulphide group, and cobalt. On one occasion a series of fourteen rocks, 

of comparatively simple composition, was completed in one month, with 

the help of an assistant who made the phosphorus and ferrous iron 

determinations. But such an output of work is more than exceptional 

and implies an unusual freedom from those occasional setbacks to 

which every chemist is exposed.

PART II. DISCUSSION OF METHODS. 

PREPARATION OF SAMPLE.

Although foreign to the above heading> a few words relative to the 

sample itself may be here appropriately inserted by way of introduction. In the great majority of cases a few chips from a hand specimen 

will well represent the average of the mass, but with rocks in which a 

porphyritic structure is strongly developed the case is different. Here 

a large sample should be provided, gauged according to the size of the 

crystals, and the whole of this should be crushed and quartered down 

for the final sample. Unless this is done, it is manifest that the analysis may represent anything but the true average composition of the rock.

Crushing. Mechanical appliances for reducing samples to fine powder 

are much in use in technical laboratories, where they answer their purpose more Or less admirably, and something similar is needed in those 

scientific laboratories where rock analysis is of daily occurrence and 

many samples must be reduced to fine powder in a short space of time. 

For accurate analyses the use of steel crushers and mortars is out of the 

question, because of the danger of contamination by particles of metal and 

the impossibility of cleansing the roughened surfaces after they have 

been in use a short time. Extraction of steel particles from the powder 

by aid of a magnet is quite inadmissible, since the rocks themselves, 

almost without exception, contain magnetic minerals. The method of 

rough crushing found to be most satisfactory in practice is to place 

each fragment as received on a hardened steel plate about 4£ cm. thick 

and 10 cm. square, on which is likewise placed a steel ring 2 cm. high 

and of about 6 cm. inner diameter, to prevent undue flying of fragments 

when broken by a hardened hammer. In this way a considerable sample can soon vbe sufficiently reduced for transfer to the agate grinding 

mortar with a minimum of metallic contamination.
DISCUSSION OF METHODS. 23

Grinding. Of the various grinding arrangements on the market 

purporting to fulfill their purpose few, if any, observed have met the 

conditions required by the work in hand. Either the mechanical 

arrangement is complicated or cumbersome, requiring more power or 

space than is usually at disposal or causing too much noise, or thorough cleansing is difficult and troublesome, or there is likelihood of 

contamination from oil or grease or lack of facility for the removal of 

all powder from the mortar. These last defects are especially prominent in those forms in which.the mortar is fixed in its setting.

All rock samples have therefore been reduced to powder by hand, 

involving a great expenditure of time and labor. Ordinarily an extremely fine state of division is unnecessary, except in the case of 

those portions in which alkalies and ferrous iron are to be estimated or 

where soluble constituents are to be removed by acids, etc., and in such 

cases the final grinding can be done at the balance table on a small 

portion slightly in excess of the quantity to be weighed Off.

The process of sifting through fine cloth, the German u beuteln," is 

one not always to be commended, because of the time required and, 

more especially, because of the certainty of contamination by cloth 

fiber, which in the ferrous-iron portion might affect the result. Still 

less should metal sieves be used.

Weight of ground sample. The sample when ground should weigh not 

less than 10 grams, and preferably 20 in case it should be necessary 

to repeat or advisable to employ unusually large portions ibr certain 

determinations, notably carbonic acid. Eock analysis has in this respect 

an advantage over mineral analysis, since material is almost always 

available in ample quantity and any desired number of separate portions may be used, whereas with a mineral the analyst is frequently 

compelled to determine many or all constituents in a single, often very 

small, portion of the powder. ' This course often involves delay and 

the employment of more complicated methods of separation than are 

usually necessary in rock analysis.

SPECIFIC GBAVITY.

By suspension in water. This determination, when required, is best 

made upon one or several fragments weighing up to 20 grams. They 

are held together by a fine platinum wire ready for suspension from the 

balance, and thus held are placed in a small beaker to soak overnight 

in distilled water under the exhausted receiver of an air pump, side by 

side with a similar beaker of water. Boiling is of course a much less 

effective means of removing air than the air pump, and the boiling 

water may exert an undesirable solvent and abrading effect. In the 

morning the wire is attached to the balance arm, the rock fragments 

remaining immersed in the water; a thermometer is placed in the com 

panion beaker of water, now likewise in the balance case, and the weight
24 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

is at once taken. Both vessels of water having precisely the same temperature, it is quite unnecessary to wait for the water to assume that of 

the balance should it not already possess it. The fragments are now 

lifted out, without touching the vessel, and carefully transferred to 

a tared crucible or dish; the wire is removed and at once reweighed, 

with the precaution that it dips just as far into the water now as when 

weighted. Hereby a special weighing of the wire out of water is 

avoided. The sample may now be dried on the water bath and then at 

110° C. for some hours to certainly expel all absorbed water, and 

weighed after prolonged cooling in the desiccator. It is better to 

ascertain the weight of the dry rock after soaking in water than before 

in order to avoid the error due to possible breaking off of a few grains 

between the two weighings. Should the density of the rock in air-dry 

condition be required, 1 it may be left exposed to the air for a lengthy 

period after drying and before weighing; but the difference will only 

in exceptional cases affect the second decimal by more than a single 

unit. For instance, a rock of 2.79 specific gravity when dry will, if 

carrying the high percentage of 0.3 per cent hygroscopic moisture 

in the uncrushed state, have a density of 2.775; a rock of 3.00 specific 

gravity dry will have a density of 2.982 if 0.3 per cent of moisture is 

included.

Reasons for preferring suspension to pycnometer methods. -^This method 

of ascertaining the specific gravity of rocks is certainly more convenient than, and for compact rocks is believed to be decidedly preferable 

to, that of the pycnometer, in which the fragments must be reduced to 

small size with consequent formation of more or less powder, which is 

subject to slight loss in the various manipulations. To exclude this powder and employ only small fragments would introduce a possible source 

of error, since it is apt to consist largely of the most easily abraded 

minerals and consequently not to have the average composition of the 

mass. By following the instructions given above, loss of material is 

absolutely avoided, a decided saving in time is effected, and considerable weights can be easily employed with consequent lower probable 

error in the results. To vesicular rocks, however, notably certain lavas, 

the above procedure is of course inapplicable, unless the datum is 

desired for certain considerations in which the relative density of large 

rock masses as they occur in nature is sought, as for the comparison of 

building stones or the calculation of large known or assumed areas of 

particular rocks.

Pycnometer methods. If the pycnometer has to be used, as is generally the case when the density of any one of the mineral ingredients of

'In view of the uncertainty as to what constitutes hygroscopic water (see p. 29), this course is 

perhaps more to be commended than the former, and seems imperative for certain zeolitic rocks. In 

such cases it is best to weigh the fragments before putting to .soak, and afterward to .collect on a 

Gooch crucible the grains which may have fallen off in the water. Should no crucible of this kind be 

available, a paper filter may unhesitatingly be used and incinerated with the powder, owing to the 

small amount of which the error due to loss of even all its. water during Ignition is quite negligible..
DISCUSSION OF METHODS. 25

a rock is desired after separation by one of the approved methods, it 

being then in'a more or less finely divided state, the most accurate procedure is that adopted in this laboratory by Mr. L. G. Eakins a number 

of years ago. The pycnometer used is one Avith a capillary stopper, 

provided with a millimeter scale .etched in the glass, the divisions being 

numbered both ways from the center and calibrated by mercury so that 

the value of each one in weights of water is known. The capacity of 

the flask filled with water to the zero division is then calculated for 

every half degree of temperature from 0° C. to 30° 0., by making a series 

of careful weighings, in which, knowing the capacity of the stem, it is 

quite immaterial at what level the water stands provided it is within 

the limits of the scale. The exact temperature is secured by an accurate thermometer placed iu a companion vessel of similar shape to. the 

pycnometer and containing a like amount of water, both being left in 

the balance case till its temperature has been nearly or quite assumed, 

as shown by a second thermometer. The weighing must of course be 

made before the thread of water has sunk beneath the lowest division, 

which it will do after a time, even though at first filling the bore to the 

top of the stopper; aud the corrected weight full of water to the zero 

mark is found by adding or subtracting the needed amount, as shown 

by the height of the thread on the scale.

Eor each pycnometer in use, and these are of different sizes, is prepared a table showing its weight, the value of each scale division in 

grams of water, and the capacity of the flask at different temperatures, 

as indicated above. The preparation of such a series of flasks is time 

saved in the end, for the weighing of the flask full of water each time 

a density deterurination is made is rendered superfluous. All that is 

necessary is to look up in the table the weight corresponding to the 

temperature.

The density of the previously weighed substance in this case is now 

determined in much the same way, after the unstoppered pycnometer 

containing it and nearly filled with water has stood with its companion 

vessel of water under the air pump the necessary length of time. The 

water needed to fill the flask is taken from, its companion.

All Avho have used the pycnometer method for fine substances know 

the difficulty experienced in preventing a portion from being held at 

the surface, despite all attempts at making it sink. Hence it often 

happens that a very small .portion runs out around the sides of the 

stopper on inserting it. If the flask rests in a small tared dish the 

grains thus forced out may be washed down into it and weighed after 

evaporation in order to get the correct weight of that in the flask; or, 

after weighing, the contents of the flask may be emptied into a tared 

dish and the water slowly evaporated off iu order to get the weight of 

the mineral. Usually this way is less to be recommended, tliau the 

Qther.
26 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

PenfieWs method for mineral fragments. Penfield 1 recommends the 

following modification of the suspension method as more convenient 

than that by the pycnometer in many cases for small fragments of 

minerals.

After boiling in water, the substance is transferred with water to a 

small glass tube about 8 mm. by 35 mm., provided with a fine platinum 

wire for suspension. This is weighed full of water in another vessel 

of water, and again after the removal of the mineral, the weight of 

which is found after drying.

This method is, of course, more applicable to homogeneous minerals 

than to rock fragments, and will therefore be applied in rock analysis 

chiefly to the determination of the specific gravity of the mineral 

grains separated by heavy solutions or acids.

Heavy solutions not available in case of rocks. Because of their roughness, porosity, and complex mineral composition the density of rock 

fragments can not be accurately determined by that of heavy solutions 

in which they may remain suspended.

WEIGHTS OF SAMPLE TO BE EMPLOYED FOB ANALYSIS.

With only occasional exceptions nearly all the constituents mentioned on p. 21 can be estimated, if present, in 1 gram of rock sample. This is a convenient weight to take for the main portion^in which 

silica, alumina, etc., the alkaline earths, and magnesia are to be sought, 

but it should in general be a maximum, because if larger the precipitate of alumina, etc., is apt to be unwieldy. Its weight can not often 

be much reduced with safety- if satisfactory determinations of manganese, nickel, and strontium are to be expected. For the alkali portion one-half gram is a very convenient weight. In general it may be 

made a rule not to use more than 2 grams for any portion which has to 

be fused with an alkaline carbonate, as for sulphur, fluorine, chlorine. 

For carbon dioxide the weight may rise to 5 grams or even more, if 

the amount of this constituent is very small, without expenditure of 

any more time than is required by 1 gram, and with correspondingly 

greater approach to correctness in the result.

WATER HYGROSCOPIC.

Importance of not drying before weighing. The time-honored custom 

of drying a powdered specimen before bottling and weighing has long 

seemed to the writer one that has no sound basis in reason. Its object 

is of course plain, namely, that of securing a uniform hygroscopic condition as a basis for convenient comparison of analytical results, since 

some rocks contain more hygroscopic moisture than others. Nothing, 

however, is more certain than that by the time the substance is weighed 

it has reabsorbed a certain amount of moisture, small, indeed, in most

1 Am. Jour. Sci., 3d series, Vol. L, p. 448, 1895.
HILLEBHAND. DISCUSSION OF METHODS. 27

cases, but very appreciable in others; and further, with every opening 

of the tube moisture-laden air enters and is inclosed with the remainder 

of the dry powder. It therefore may very well happen that a powder 

at first dry will," after several openings of the tube, especially at considerable intervals, be nearly as moist as when first inclosed.

It is preferable to weigh the air-dry powder and to make a special 

determination of moisture at 100° or 110° 0. If all the portions necessary for an analysis are weighed out one after another, or even at 

different times on the same day, the error due to difference of hygro-' 

scopicity in dry and moist weather, which for most of the separate portions is an entirely negligible quantity, is eliminated. Only in the 

main portion, in which silica and the majority of the bases are to be 

estimated, can it ever be an appreciable factor.

Temperature of drying. As to the temperature to be adopted for 

drying in order to determine so-called hygroscopic moisture, the practice has varied at different times and with different workers, ranging 

from 100° to 110° C. For the great majority of rock specimens it is 

quite immaterial which of these temperatures is adopted, since no 

greater loss is experienced at the higher than at the lower temperature, 

given a sufficient time for the latter. Since the drying is accomplished 

more rapidly at 110° than at 100°, it is the present practice in this 

laboratory to employ the higher temperature. Should the results show 

a very unusually high loss, the powder is reheated at, say, 125°, in 

order to learn if the loss is progressive with increased temperature. In 

the affirmative case it may be well to repeat the drying at 100°, for a 

portion of the loss at 110° was probably due to combined water from a 

mineral or minerals in the rock; but in that case even the loss at 100° 

may sometimes very well include combined Avater, and a further drying 

over sulphuric acid alone may be desirable, or over dry sand.

Cautionary hints. In this latter connection it is proper to point out 

certain pitfalls in the path of the unwary, which, however, are far more 

apt to be encountered in the analysis of minerals, where their influence 

may be of far-reaching consequence.

A mineral which loses a great deal of water over sulphuric acid 2 or 

3 per cent, for instance may need an exposure of several days or even 

weeks for its complete extraction. If the weighings are made from 

day to day, the apparent limit may be reached long before all water 

really removable has been taken up by the acid. Whenever the crucible, after weighing, is replaced in the desiccator, it is no longer in a 

dry, but a more or less moist atmosphere, and its contents, even when 

covered, sometimes absorb a part of this moisture and retain it so persistently that the acid is unable to bring the powder beyond its previous 

state of dryness in the next twenty-four hours. In fact, it may be 

unable even to reach it unless greater time Is allowed. An experiment 

on 1 gram of tyrolite, made and published some years ago, seems to 

illustrate this point in part.
28 ANALYSES Otf ttOCItS AND ANALYTICAL METHODS.

Hours 

exposed.

18

26

23

24

23

24

25

Loss.

Gram.

.0231

. 0083

.0029

.0012

f\r\f\Q

.0001

.0003

Hours 

exposed.

24

24

48

24

283

Loss.

Gram.

.0002

.0003

.0006

.0002

.0380

The experiment might reasonably have been considered ended after 

the one hundred and fifty-eighth hour, when a loss of but 0.1 milligram 

was shown during twenty-four hours; but nevertheless a nearly steady 

loss of 0.3 milligram per day took place for six days more, and might 

have been longer observed but for the interruption of the experiment.

Again, it is sometimes desirable to determine the water given off by 

hydrous minerals in an air bath at temperatures far above 100° 0. To 

insure accuracy, this experiment should not be made in crucibles or 

dishes which must be cooled in a desiccator. One instance Avill suffice: 

A gram of a mineral mixture containing about 17 per cent of water, of 

which about 3 per cent was driven off at 100° and 8 or 9 per cent at 280°, 

was, after several hours' heating, placed in a desiccator over sulphuric 

acid and weighed as soon as cold, then replaced and again weighed the 

next day. It had gained 1£ per cent of its original weight, although 

the desiccator was tightly closed and the crucible covered, showing 

apparently a drying power superior to that of the acid.

A specimen of tyrolite was found on one occasion to lose 10.34 per 

cent at 280° C., and on another occasion 14.33 per cent. In the latter 

case the drying and heating at progressive temperatures had continued 

during' a period of 528 hours, the weighings being made usually from 

day to day; whereas in the former the duration of the experiment was 

much shorter and the intervals between weighings were but a few 

hours each.

Procedure in special cases. For experiments of this nature the powder should be heated in a weighed tube, through which a current of 

dry air can be passed, and allowed to cool therein, or else the water 

given off should be collected and directly weighed in suitable absorption tubes, 1 even though the long time often required is an objection to 

this latter method, since the absorption tube may gain weight, other 

than that of the water from the mineral, sufficient to introduce an 

appreciable error.

The recent important research of FriedeP well shows what errors are

'Jannasch and Locke, Zeitschr. fur anorg. Chemie, Vol. VI, p. 174, 1894, describe and depict a form 

of apparatus adapted for either method of ascertaining hygroscopic water. 

2Bull. Soc.Min., Vol. XIX, pp. 14, 94, 1896; Comptes Kendus, Vol. CXXII, p. 1006,1896.
DISCUSSION OF METHODS. 29

possible in the determination of this easily removable water, since he 

found that certain zeolites which had been largely dehydrated but not 

heated to the point of rupture of the molecular net, could then absorb, 

instead of water, various dry gases in which they might be placed, as 

carbon dioxide, ammonia, carbon disulphide, and others, even air in 

large quantities, and certain liquids. In the light of this observation 

the cause of the great increase of 1£ per cent in weight of the partially 

dehydrated mineral mentioned on p. 28 may very possibly be attributed 

to air from the desiccator instead of moisture, as was at the time supposed. At any rate, as Friedel says, the danger of accepting a loss in 

weight as an index of the amount of water lost is clearly shown, and 

thus that method of determining water is for many cases fully discredited. Just what method to adopt must be largely left to the judgment 

of the operator, who will often be guided by the mineral composition 

of the rock as revealed by the unaided eye or the microscope.

Friedel (loc. cit.) indicates a means for determining the true weight 

of water lost by minerals behaving like the zeolites, even without collecting the water lost, namely, by driving out of the dehydrated and 

weighed mineral, under proper precautions, any air it may have absorbed 

in the process of drying and cooling, and collecting and measuring this 

air and thus finding its weight, which, added to the apparent loss, gives 

the true contents in water.

Argument in favor of including hygroscopic ivater in summation. The 

question has been asked: " If the so-called hygroscopic water is not 

always such, but not infrequently includes combined water, why is not 

its determination and separate entry in the analysis entirely unnecessary ? Why make a distinction which; after all, may not be a true one*?" 

The question involves the further consideration of the advisability of 

including in the analysis at all the loss at 100° or 110° 0. Many petrographers desire to have all analyses referred to a moisture-free basis, 

in order that they shall be strictly comparable, and therefore would 

omit the "hygroscopic" water from the list of constituents. This would 

be eminently proper were it always possible to be sure that the loss at 

100° truly represents mechanically held water. Since it very often 

represents more, and the determination as to whether or not it does in 

each case is not always possible, and would add to the time required for 

the analysis, it seems necessary to include this \rater. What errors 

may arise from its exclusion the following rather extreme case well 

illustrates: Certain rocks of Wyoming in powder form lost from 1 to 2 

per cent of moisture at 110°. That not.even an appreciable fraction of 

this was truly hygroscopic the fact of the uncrushed rocks losing the 

same amount fully demonstrates; yet the rule followed by many chemists and petrographers would have involved the removal of all this 

water as a preliminary to beginning the analysis, and not only would 

a most important characteristic have passed unnoticed, but the analyst 

would have reported an incorrect analysis, inviting to false conclusions, 

and possibly serious confusion.
30 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Separate entry of hygroscopic and combined ivater. To revert now to 

the primary question, it may be said that the estimation of the loss at 

100° or 110° 0. and its separate entry in the analysis is advisable as 

not infrequently affording at once to the lithologist an indication of the 

mineral character of one or more of the rock constituents, thus perhaps confirming the microscopical evidence or suggesting further 

examination in that line. An unusually high loss at 100° would be 

regarded as probable evidence of the presence of zeolites or other minerals carrying loosely combined water. It has been objected that the 

true hygroscopic moisture varies with the degree of comminution of the 

sample and with the condition of the air at the time of weighing, and 

that it is therefore improper to incorporate it in the analysis; but this 

variation is ordinarily not at all great. Perhaps the time may come 

when it will be the rule to ascertain by additional heating at a higher 

temperature whether the water lost at 100° is to be regarded as purely 

hygroscopic. In such case it would be proper to omit it, and a distinct 

advance would undoubtedly be scored.

Is all true hygroscopic water expelled at 100°? It has been tacitly 

assumed in the foregoing that true hygroscopic water can all be expelled 

at 100°, which perhaps is not to be accepted as universally true. Eminent authority holds that it is impossible, in the cases of certain foliaceous minerals, notably the micas, to thus entirely remove it, but that 

a part is only driven off at higher temperatures. If this is true a further uncertainty is introduced in its determination, which not only 

strengthens the argument in favor of entering all water in the tabulation, but also serves to emphasize the difficulties of the situation.

WATER TOTAL OR COMBINED.

Arguments against " loss on ignition " method. In a few cases the 

simple loss on ignition of a rock will give the total water with accuracy, 

but in the great majority there are so many possible sources of error 

that this old-time method can rarely be used with safety. Only when the 

rock is free from fluorine, chlorine, sulphur, carbon, carbon dioxide, and 

fixed oxidizable constituents can the loss be accepted as the true index 

of the amount of water present, and it is rarely that a rock is met with 

fulfilling these conditions, especially as to the absence of ferrous iron. 

Blast ignition in presence of carbon dioxide alone of the above list 

may give a correct result, after separate estimation of the carbon dioxide, provided this emanates from carbonates of the earths and not from 

those of iron or manganese. The long-maintained and still upheld 

idea that in presence of ferrous iron a sufficiently correct result is 

obtainable by adding to the observed loss an amount needed for oxidizing all ferrous iron is not justifiable. There can be .no certainty that 

the oxidation has been complete, especially in the case of'readily fusible 

rocks, and at the high temperature of the blast a partial reduction of 

higher, oxides is not only possible but sometimes certain, The inability
DISCUSSION OF METHODS. 31

to insure complete oxidation by simple ignition is illustrated in the 

case of precipitated ferric hydroxide, which has been ignited together 

with its filter paper. If the quantity was in any degree large it is 

sometimes decidedly magnetic, presumably from presence of magnetic 

oxide, which no amount of heating wholly oxidizes, especially in the 

larger grains.

Brush and PenfieWs method. Direct weighing of the water evolved 

is, then, imperative in most cases, and if no other volatile constituents 

are present the beautifully simple method first used by Prof. Or. J. 

Brush and extended by Prof. S. L. Penfield 1 leaves nothing to be 

desired for accuracy. It consists simply in heating the powder in a 

narrow tube of hard glass, enlarged at the closed end and provided 

with one or two further enlargements in the middle to hold the water 

and prevent its running back and cracking the hot glass. A capillary 

glass stopper, fitted in with rubber tubing, prevents the loss of water 

by circulating air currents. The tube being held horizontally, the bulb

is heated to any required degree, either in the blast alone or the simple combination of blast with charcoal backing used by Penfield, which 

gives the white heat requisite for complete expulsion of water in some 

cases. Moistened filter paper or cloth wound about the cooler parts of 

the tube insures condensation of all water. The heated end being 

finally pulled off, the tube is weighed after cooling and external cleansing, and again after the water has been sucked out by aspiration. For 

most rocks, as they contain little water, central enlargements of the 

tube are hardly needed.

How this simple apparatus is made to afford entirely satisfactory 

results, even when carbonates are present, is fully set forth in the paper 

cited.

Few rocks, comparatively, are altogether free from other volatile constituents 5 hence for refined work the application of this apparatus in 

the simple manner above set forth is limited. It may, however, be used 

with the addition of a retainer for fluorine, sulphur, etc., in the shape 

of calcium, lead, or bismuth oxides, or even with sodium carbonate.

In whichever way used the water found is the total water, from which 

that found separately at 110° 0. may be deducted if desired.

Gooch's apparatus. Of more elaborate apparatus designed to be used 

with fluxes the tubulated platinum crucible invented by Dr. Gooch2 is 

capable of affording most excellent service, and it is the one by which 

far the larger number of water determinations in this laboratory have 

been made. Since its manner of use is probably not generally known, 

some directions may not be amiss. A detailed description of the apparatus itself would not be clear without a figure, but it may be said that 

the form now used differs from that figured in Gooch's paper and his 

subsequent slight modification of it, in that the tubes for connecting

'Am. Jour. Sci., 3d aeries, Vol. XLVIH, p. 31,1894. Zeitsch. fur anorg. Chemie., Vol. VII, p. 22,1894. 

2 Am. Chem. Jour., Vol. II, p. 247,1880.
32 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

with both the drying and absorption vessels are constructed wholly of 

platinum instead of lead glass, the vertical one being bent horizontally 

,at right angles for convenient attachment to the drying towers, and the 

side one also bent at right angles, but downward, so as to admit of 

insertion in the rubber stopper of a U-shaped calcium chloride tube. 

The length of the vertical tube, including its horizontal part from top 

of cap, is 13£ cm.; that of the side tube is 12 cm. The end of the latter 

is drawn in slightly, so as to enter the rubber stopper of the absorption 

tube without scraping it. With tubes of the lengths above given there 

is absolutely no danger of their ends becoming hot enough by conduction to scorch or soften the rubber stopper or other connection.

The extra first cost of the platinum extension to these tubes over 

the lead-glass ends of Gooch's original and modified forms need hardly 

enter as a factor in the question of employment of this apparatus. The 

glass ends often break, and only a rich lead glass, not easily obtainable, can be used, since it alone will not crack at the joint with the 

platinum after cooling. In its present form the whole apparatus 

weighs approximately 88 grams.

As an adjunct to its convenient use there is needed an ordinary 

upright iron ring-stand, with one small sliding ring, and above this a 

sliding ring-burner provided with entering ducts for gas and air blast. 

Still above this is another small ring, across which there is an arrange- 

-ment of stout platinum wire, forming at the center of the ring a secure 

seat for the upturned flange of the crucible proper. Both rings and 

burner can be clamped firmly at any height.

The rock powder, having been placed in the cylindrical crucible, is 

there mixed with not more than 3 or 4 grams of fully dehydrated 

sodium carbonate,1 or more of lead chromate if carbon is to be likewise 

determined, the crucible is sunk in its seat in the upper ring, and the 

tubulated cap is fitted on and attached to the calcium chloride drying 

towers on the one side and to a sulphuric acid bulb tube on the other. 

Powdered sodium tungstate free from arsenic, which would soon ruin 

the crucible lips is now poured into the flanged lip in which the cap 

rests, and a metal vessel of cold water having been raised up by 

the lower ring until the platinum crucible is sufficiently immersed, the 

blast-fed flame of the ring burner, or that of an ordinary blast lamp, 

if at hand, is turned on to melt the tungstate. As soon as this is 

fused the flame is removed and the salt solidifies and makes an airtight joint, the test of which is the permanence of the column of sulphuric acid in the bulb tubes caused by the contraction of the air in 

the platinum apparatus as it cools.

After drying by a current of air at 110° 0. for a couple of hours, more 

or less (see below), the absorption tube is interposed between the sulphuric acid bulbs and the apparatus, being fitted to the latter by its

1 This has been heated for a length of time to near its fusing point over a free flame or in an air bath, 

to decompose the bicarbonate it usually contains, and then placed in a desiccator.
HILLEBRAND. DISCUSSION OF METHODS. 33

stopper, which is at other times closed by a glass plug, and while a slow 

current of air continues to pass the gradual heating and subsequent 

fusion of the flux is brought about by the blast-fed sliding ring-burner. 

When fusion is complete, as shown in the case of sodium-carbonate flux 

by the decided slackening of the gas current through the safety bulbs 

attached to the drying tube, the flame is extinguished and a current of 

air is allowed to continue until the apparatus is cold.

This apparatus suffers from the drawback of being slightly permeable 

to combustion gases at high temperature. The defect can be overcome 

by causing the flame to play upon an outer ordinary platinum crucible, 

 kept permanently filled with sodium-potassium carbonate. This protective crucible, however, is soon ruined for other purposes, being distorted by the alternate expansion and contraction of the carbonate.

It has been found that if the operation is carried out expeditiously 

and the final full heat applied for but a few minutes the error due to 

penetrating water gases is inappreciable. This hastening may be rendered safer by using rather finely powdered calcium chloride in the 

central section of the U-shaped absorption tube to avoid large air channels. Through this, or any apparatus based on similar principles, the 

air current should always be forced, not drawn. A warm blast directed 

upon the exit tube near its entrance into the absorption tube greatly 

shortens the time required and is to be recommended.

In this apparatus only the water expelled above 100° to 110° should as 

a rule be determined, and to effect drying of the mixed mineral powder, 

and sodium carbonate, after luting the tubulated cap on the cylindrical crucible with sodium tungstate, the tube is sunk through a round 

hole in the cover into a small cylindrical air bath, which can be heated 

from beneath by the same ring burner which is subsequently to fuse 

the flux. A slow current of air is then forced through and the drying, 

satisfactorily accomplished. , The reason why it is unsafe to attempt estimation of "hygroscopic" 

moisture in this apparatus is, that the luting of the two parts must be 

done by direct application of a flame to the tungstate, and considerable 

water vapor may enter the apparatus and be in part retained by the 

dried sodium carbonate.

Chatard's apparatus. The platinum apparatus, devised by Dr. Ohatard 1 overcomes the permeability of the metal to gases and affords 

sharp results', moreover permitting of determining by direct absorption, 

not only the hygroscopic water, but that which may be driven off at any 

desired temperature. It is, however, more costly than the Gooch appa-. 

ratus, and the supposed nonliability to injury by warping, because of 

the protective layer of borax and asbestus, can hardly be considered as. 

prove*d.

PenfieWs second method. Simplest of all, and permitting by the use. 

of auxiliary arrangements such as shown in Ohatard's paper of deteri Am. Chern. Journ., Vol. XIII, p. 110, 1891; Bull. U. S. Geol. Survey No; 78, p. 84, 1891.

Bull. 148 3
34 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

mining the hygroscopic as well as any other, traction of the water, is the 

glass tube arrangement described on page 37 of Dr. Penfield's article 

cited on page 31.

All of these apparatus, except the first-mentioned glass tube, permit 

of the estimation of other constituents besides water in the same portion if necessary, and by the use of lead chrornate or potassium chroinate instead of sodium carbonate, graphite, or the carbon of organic 

matter, can be simultaneously determined with the water.

To one accustomed to its use, and with a drying and suspension 

attachment permanently set up, the Gooch apparatus, considering its 

limitations above set forth, offers perhaps the most handy and convenient means for the determination of water in rocks. Its high first cost, 

in comparison with the glass tube, is fully made up in time by its 

durability.

JannascWs methods. That most zealous deviser of improved methods 

in mineral analysis, Prof. P. Jannasch, has published in the Zeitsch. 

fur anorg. Chemie and the Ber. Deutsch. chem. Gesell., several papers 

dealing with the problem of water determination in minerals besides 

the one already cited. Beginning with lead oxide as a flux, he subsequently experimented with lead chromate, borax, and boric acid, finding 

all of these to give accurate results in most cases when his directions 

are carefully followed, but unfortunately not capable (with the exception, perhaps, of lead chromate), like sodium carbonate, of general 

applicability, since with certain minerals one or the other fails to effect 

complete decompositibn or to retain all volatile constituents. Especially 

for these reasons, also because the methods have not been tested in 

this laboratory and because Professor Jannasch is still engaged in 

extending the boric-acid method, their use is not at present advocated 

for rock analysis. Moreover the rock must be in such an impalpable 

powder for the boric-acid decomposition that a half to one hour has to 

be expended in the grinding of one gram or less a serious consideration 

for the busy chemist.

SILICA, ALUMINA, ETC.

Remarks on alternative methods .of decomposition. Various fluxes 

other than alkaline carbonates have been recommended for breaking 

up silicates insoluble in ordinary acids, such as lead and bismuth oxides, 

lead carbonate, bbrax, and boric acid. Prof. P. Jannasch and his 

pupils have been especially active of recent years in this line of work, 

as evidenced by their numerous published papers. One of the advantages these fluxes possess over the alkaline carbonates is their removability after serving their purpose, thus allowing the various separations 

to be made more perfectly and without the annoying interference of 

several grams of foreign fixed salts, which are most troublesome in that 

part of the analysis devoted to the separation of silica, alumina, iron, 

lime, and magnesia.
DISCUSSION OF METHODS. 35

Another of their advantages is that with some of them it is possible 

to estimate in one portion the alkalies, in addition to those constituents 

usually determined in the silica portion. Where the material is limited, 

as it so often is in mineral analysis, this is a most important advantage, 

sufficient to outweigh all possible objections; but in rock analysis, where 

the supply of material is usually ample, it is rarely worth considering. A still further point in their favor is that it is probably more 

easy to obtain them entirely free from fixed impurities than an alkaline 

carbonate.

There are, however, objections to their use. With some of them an 

extraordinary amount of time must be devoted to grinding the mineral 

to an impalpable powder, and the flux itself may need considerable 

hand pulverization. Once introduced, they must be removed before the 

analysis can be proceeded with, and this removal takes much time and 

is always a possible source of error. The expulsion of boric acid and 

drying of the silica in the recent method of Jannasch and Heidenreich,1

from their own account, requires the almost constant supervision of the 

chemist for several hours. In mineral analysis these objections are entitled to far less weight than in rock analysis, since the object sought 

usually the deduction of a formula warrants the expenditure of much 

time and painstaking care. Finally, it has been found that one or more 

of these fluxes are not available for altogether general use, since certain 

minerals do not fully succumb to their attack, as andalusite with boric 

acid and others with lead oxide (Jannasch). Therefore, however well 

adapted one or the other of these methods may be for the analysis of 

homogeneous minerals, it is very improbable that the vivid anticipations of Professor Jannasch,2 to the effect that the boric-acid method 

will soon supersede the alkaline-carbonate-fusion method in rock as well 

as mineral analysis, will be speedily realized. Nor can the great saving in time of 50 per cent which is claimed be for a moment admitted. It 

may be that a chemist attending to only one analysis at a time will finish 

it somewhat sooner by following. Professor Jannasch's procedure than 

the one here outlined; but it is quite possible, as intimated on page 22, 

for two, or even sometimes portions of three, analyses to be carried on 

in different stages of completion at the same time by the methods herein 

set forth.

The practice of separating alumina, etc., by the usual methods, after 

first attacking the rock powder by hydrofluoric and sulphuric acids 

silica being estimated in a separate portion while attractive in principle, was abandoned by the writer after fair trial, owing to the disturbance sometimes occasioned by incomplete expulsion of fluorine and to a 

less degree by the presence of sulphates instead of chlorides. With 

exception of the comparatively few analyses made thus, the sodiumcarbonate method has always been employed. In the case of rocks 

rich in fluorine strict accuracy would require the separation of silica

1 Zeitsch. fur anorg. Chemie, Vol. XII, p. 208,1896. * £oc. cit., p. 219,
36 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

to be made as in the Berzelian method, for fluorine estimation, but in 

practice it is hardly ever necessary to resort to this tedious procedure, 

since the amount of fluorine is usually small and it can by no possibility cause a loss of much more than three-fourths its own weight of 

silica by volatilization as silicon fluoride when the sodium-carbonate 

fusion is evaporated directly with hydrochloric acid. Probably the 

loss is less, since some fluorine perhaps escapes as hydrofluoric acid. 

However this may be, the error is of comparatively slight importance, 

since it attaches to the constituent always present in greatest amount.

Purity of the sodium carbonate used as a flux. Notwithstanding the 

most earnest efforts for years, it has been impossible to procure, either 

in the open market or by special arrangement with manufacturers, an 

article of sodium carbonate which can be called chemically pure. 

With special precautions small lots can be prepared in the laboratory 

that will contain less than 1 milligram total impurity in 10 grams; but 

such an article can not be purchased in the market, and rarely will the 

so-called chemically pure dry sodium carbonate contain as little as 1 

milligram in 10 grams. The invariable contamination, aside from sand 

and straw, which have sometimes been found in large amount, is silica, 

alumina, iron, lime, and magnesia, all of these going into aqueous solution with the carbonate. The chief of these impurities are usually 

silica, alumina, and lime. An article of the above degree of purity is 

satisfactory in almost all imaginable cases, since the use of the usually 

extravagant amount of 10 grams for a fusion would introduce an error 

of but 0.1 per cent in the analysis, supposing 1 gram of mineral to be 

operated on. This error is undoubtedly fully equaled by the introduction of dust from the air in the various long evaporations.

Precautions in fusing. Special directions with regard to the fusion 

aud its first treatment are unnecessary, except to say that the flame 

should not be directed vertically against the bottom of the crucible, 

but at an angle against the side and bottom, nor should the flame be

allowed to envelop the whole crucible. These precautions apply in all 

ignitions of reducible substances, and yet they are rarely observed. 

In neither case, if neglected, will there be the necessary oxidiziug 

atmosphere within the crucible; on the contrary, reduction may occur 

fraught with serious consequences. This is especially true if the rock 

contains more than traces of pyrite or other sulphide, when, after 

cleansing and igniting the crucible, there may appear on its interior a 

darkening due to oxidation of reduced iron which had alloyed with the 

platinum. This may in exceptional cases amount to several milligrams 

in weight, and can be removed only by repeated ignitions, followed each 

time by scouring or treatment with hydrochloric acid. In order to 

avoid the use of niter in case of pyritiferous rocks, it is well to first 

roast the weighed powder in the crucible in which the fusion is to be 

made. 

It sometimes happens that the cooled flux, and even its solution,
DISCUSSION OP METHODS. 37

will indicate absence of manganese when it is really present in quantity to give normally a strong coloration. Two fusions made side by 

side or successively, under apparently similar conditions, may in one 

case show little or no manganese; in the other considerable. This 

observation has been frequently made, and therefore the absence of a 

bluish-green color in the fusion is not to be taken as proof of the absence 

of manganese. This difference of behavior I can ascribe to no other 

cause than that of a reducing atmosphere in one of the crucibles and 

an oxidizing one in the other, even though the conditions were apparently alike.

Drying and testing of silica. As to the best way of rendering silica 

insoluble by evaporation, my own predilection is for a double evaporation instead of a single one on the water bath. By'fusing with sodium 

carbonate in the forenoon, the silica is ready for the first filtration in 

the afternoon. It is quite unnecessary to carry the evaporation beyond

approximate dryness. The filtrate is again evaporated, always in platinum, and is ready for final filtration the following morning, when approximately 1 per cent of silica is recovered and added to the main 

portion. My experience is that a better separation of silica is effected 

hereby, and in no more time than by a single long evaporation. That 

which is subsequently recovered from the ammonia precipitate rarely 

exceeds a half or, at the most, 1 milligram.

Drying in an air bath at 110° C. or higher, or on a hot plate or sand 

bath, or over a free flame, in order to render silica insoluble, offers no 

advantage unless much magnesium is present, and then the most favorable temperature, according to Gilbert, 1 is 120° C. The presence of 

much calcium chloride seems to facilitate dehydration of the silica, while 

magnesium chloride above 120° C., by decomposing, forms a silicate 

which dissolves in hydrochloric acid and increases the amount of silica 

carried into the filtrate. It does not appear from Gilbert's paper that 

the blast-furnace slags, on which he experimented, contained titanium, 

phosphorus, or iron in appreciable amounts. Basic magnesian rocks 

usually do, and in such cases it is doubtful if the employment of a drying temperature of 120° would not materially add to the large impurity 

always to be expected with the silica. In other cases he confirms the 

earlier belief that drying temperatures higher than that of the water 

bath increase the amount of insoluble impurity, chiefly alumina, in the 

silica, and that this amount can not be reduced by long digestion with 

hydrochloric acid. Further, he confirms Lindo's statement that evaporation with sulphuric acid till the appearance of white fumes gives a 

higher result in silica than with hydrochloric acid. But for general 

rock analysis the use of sulphuric acid at this stage must be rejected 

utterly.

Blasting for twenty to thirty minutes is necessary to expel all moist1 Technology Quarterly, Vol. Ill, p. 61,1890. Abstract in Fresenius'a Zeitschr. fur aiial. Chomie, Vol. 

XXIX, p. 688,1890.
38 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

ure from the silica. Its weight should always be corrected for impurities, which are never absent, by evaporating with hydrofluoric and 

sulphuric acids and again blasting. If toward the end of evaporation 

with these acids, when the hydrofluoric acid has been driven off and 

the sulphates begin to appear in solid form, the residue has a peculiar 

milky or enamel-like appearance, it may be taken as evidence of much 

phosphorus and titanium.1 This appearance is so unusual and striking 

that it is worth while calling attention to it. With basic rocks very 

rich in titanium and phosphorus the residue may amount to 2 or even 

3 per cent of the rock.

The subsequent precipitate of alumina, etc., is usually ignited in the 

crucible containing the residue from the silica.

It might be supposed that this residue would contain most of the 

barium of those rocks carrying that element together with sulphur or 

sulphates, but the reverse is true as a rule. Only when there is a considerable excess of SO3 over the BaO will much of the latter be found 

there, and usually there is none at all. Should some be present, its 

removal and estimation at this stage is not necessary, as it can be more 

conveniently recovered later, together with the silica accompanying the 

alumina, etc., precipitate.

The separation of silica in rocks containing fluorine has been touched 

upon in commenting on the sodium carbonate method of fusion (p. 35).

Platinum in filtrates. The filtrates from the silica always contain 

notable amounts of platinum. This arises in very small degree from 

the crucible fusion, in a larger one from the action of hydrochloric acid 

on manganate and permanganate, sometimes chromate of sodium, and, 

if much iron is present, in no small degree from the reduction of ferric 

chloride to ferrous by the platinum of the dish. This reaction is little 

known, apparently, but is mentioned in Ginelin-Kraut 2 and can be readily demonstrated by evaporation of ferric chloride in platinum,

Metals of the hydrogen sulphide group. The presence in appreciable 

amounts of metals precipitable by hydrogen sulphide, except perhaps 

copper, is of such infrequent occurrence in most rocks that discussion 

is unnecessary in their connection. In case it is necessary to precipitate them, however, it is always well to bear in mind that some titanium 

may be thrown down along with them. Separations of the silica should 

be made in porcelain, to eliminate platinum, or, better still, the quantitative estimation of any of these metals should be made in a separate 

portion of the rock broken up by the action of hydrofluoric and sulphuric acids.

Alumina, etc. The removal of platinum from the filtrates before precipitating alumina and iron is quite unnecessary, and to do so would 

involve the reexidation of all iron and subsequent boiling to remove

1 It is possible that this appearance is caused by zirconium with the phosphorus and titanium. (See 

p. 40, footnote.) 

* Aiiorg. Chem., Vol. Ill, p. 359. Sixth revised edition.
DISCUSSION OF METHODS. 39

or destroy^ the excess of oxidizing agent, together with the waste of 

much valuable time. The iron is already oxidized by the fusion, and 

needs no further help in that direction.

Two precipitations by ammonia are usually quite sufficient to separate iron, alumina, phosphoric acid, chromium, titanium, and zirconium, if all these are present, from nickel, manganese, the alkaline 

earths, and magnesium, provided ammoniacal salts are present in sufficient quantity. This last point is of special importance as regards 

magnesium, and failure to observe it is doubtless the reason why many 

old analyses and sometimes modern ones show utterly improbable percentages of alumina, especially as chemists were formerly often satisfied with a single precipitation. The necessary ammonium chloride is 

better obtained by the use of purified ammonia water and hydrochloric 

acid than by the addition of the solid salt, which is seldom pure.

Manganese not always separated by ammonia. But it will occasionally 

happen that the separation from even very small amounts of manganese is altogether incomplete, and the uncertainty of insuring this 

separation has led the writer of late to employ the basic acetate 

method for the first precipitation in all cases where manganese is present and the-exceptions are few even though the precipitation of 

alumina is sometimes less complete than by ammonia.1 Not more than 

2, or at most 3, grams of sodium acetate need be used. After slight 

washing the precipitate is redissolved in a sufficient excess of hydrochloric acid and reprecipitated by ammonia in slight excess. The complete boiling off of this excess is unnecessary, as pointed out by Genth 

and Penfield, since it is apparently the washing with pure water and 

not the free ammonia which carries small amounts of alumina into the 

filtrate. Penfield and Harper 2 recommend washing with a dilute solution of ammonium nitrate (20 c. c. nitric acid, neutralized by ammonia, 

to the liter), and also the solution of the first precipitate in nitric 

instead of hydrochloric acid, in order to shorten the washing, there 

being no chloride to remove.

The filtrates are strongly concentrated separately 3 in platinum, a drop 

or two of ammonia being added toward the end to the second one, and 

filtered successively through the same small filter into a flask of 150 to 

200 c.c. capacity, the ammoniacal filtrate serving as wash water for the 

first dish and containing enough ammouiacal salt to prevent precipita-

'The fact must not be overlooked that certain of the rare earths may pass completely into the 

filtrate if the hasic acetate method is followed. If then, later, on rendering the combined filtrates 

ammonical, an unexpectedly large precipitate appears, this should be carefully examined as to its 

nature. In an analysis of piedmontite from Maryland over 2 per cent of rare earths, including cerium 

and others not identified, were quantitatively separated in this way from iron, alumina, etc.

'Am. Jour. Sci., 3d series, Vol. XXXII, p. 112, 1886.

8If, instead of sodium acetate, ammonia alone has been used to precipitate alumina, etc., it has sometimes happened in the experience of others than the writer that on concentration of the first filtrate 

a pale straw-colored precipitate appeared which'romained on the filter with the traces of alumina that 

may also separate, although it is slowly soluble in hot water. This'is some compound of platinum, 

and attention is called to it here, for the guidance of others who may notice it iwd be unaware of its. 

character.
40 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

tion of magnesium in the first filtrate when mixed with it. If manganese has been deposited upon the surface of the dish it is removed 

by hydrochloric and a drop or two of sulphurous acids, which mixture 

is then passed hot through the filter. A reprecipitation by ammonia is 

then made, and the precipitate collected again on the filter and added to 

the main one, the filtrate passing into the flask containing the previous 

one. If much manganese is present, of course a second precipitation by 

ammonia, of the small precipitate, may be required. In these cases 

there is no difficulty in getting all the manganese into the filtrate.

Treatment of the alumina precipitate. The combined alumina, etc., 

precipitates are ignited moist, in the paper, unless considerable iron is 

present, when the main one is dried, removed as far as possible from 

the paper, and the latter ignited separately to prevent partial reduction of a portion of the iron, which can not then be reoxidized by heating (see p. 31).

Alumina in the quantities ordinarily found can not be fully dehydrated by the full heat of the Bun sen burner. It must be blasted for 

five or ten minutes. If iron is present in large amount this last operation must be conducted so as to insure free access of air to the crucible 

(p. 36).

Estimation of silica and iron in the alumina precipitate. The precipitate is dissolved by fusion with acid potassium sulphate, an operation 

which is accomplished without trouble in from two to four hours if the 

temperature is kept low and the acid salt has been properly made free 

from water and excess of acid. The melt is taken up with hot water 

and considerable dilute sulphuric acid, the -residue collected, weighed, 

ami corrected by hydrofluoric and sulphuric acids for silica, which, as 

said before, rarely amounts to 1 milligram in weight, and further examined for barium (see p. 38) by dissolving in hot, strong sulphuric acid 

and diluting with cold water. 1 The filtrate is reduced, hot, by hydrogen 

sulphide, boiled to collect the sulphur and platinum sulphide resulting from the bisulphate fusion, the hydrogen sulphide being allowed 

to pass for a short time after boiling.2 It is then filtered 3 hot into a

'Some years ago, in a series of analyses of rocks from the Lencite Hills, in Wyoming, there was 

obtained at this stage, when it was customary to dissolve the melt in cold water only preliminary tp 

precipitation of titanium by boiling the neutralized sulphuric solution in presence of sulphur dioxide, a white, more or less flocculent residue amounting to 1 to 3 per cent of the rock, which was at first 

taken to be a mixture of tantalic and columbic acids. Eventually it was found to consist apparently 

of nothing but TiOj and PjOc, with perhaps a little Zr02 . By repeated fusion with acid potassium 

sulphate and leaching with cold water it could bo gradually brought into solution. It was these rocks 

which furnished the most striking instance of the peculiar, milky, sulphate residues mentioned on 

p. 38, as derived from the ignited silica.

Knop (Zeitschr. fiir Kryst., Vol. X, p. 73, 1885) seems to have obtained a similar mixture in analyzing minerals from the Kaiserstuhl in Baden, but its nature was not ascertained, though suspected to 

be, if not silica, columbiferous titanic acid.

JIt may be mentioned that the precipitation of platinum from a hot sulphate solution is far quicker 

and cleaner than from hydrochloric acid.

filtration is not necessary if only precipitated sulphur and no sulphides are in suspension, since 

this is without reducing action on cold permanganate solution, as Wells and Mitchell, and others 

before them, have'pointed out. The above authors used this method of reducing ferric iron in-titanic 

iron ores. (Jour. Am. Chem. Soc., Vol. XVII, p. 78, 1895; also Chemical News, Vol. LXXIII, p. 123, 

1896.)
DISCUSSION OF METHODS. 41

flask attached to a carbonic acid apparatus, and brought to boiling to 

expel hydrogen sulphide. When this is fully effected the flask is 

cooled in water while the carbon dioxide still passes, and the solution 

is then titrated by potassium permanganate. The results are strictly 

accurate when care is taken with the reduction by hydrogen sulphide, 

and the method is altogether superior to that of reduction by zinc, 

since no foreign impurity affecting the result is introduced, and the 

ever-present titanium is not also reduced. If this latter element has 

not already been tested for, its relative amount can be conveniently 

ascertained by adding hydrogen peroxide to the titrated ferric solution. 

Alumina found by difference. In this laboratory titanium and phosphorus are estimated in separate portions, and likewise zirconium and 

chromium if present. The alumina is always found by difference after 

deducting their sum as oxides and the total iron as ferric oxide from 

the combined weights. This throws upon the alumina all errors

involved in their separate determinations, but these may balance, aud

in any case the probable error can hardly be as high as that involved 

in the direct weighing of the alumina itself, considering the difficulty 

of effecting a satisfactory separation of it from all the other admixtures, an operation which would, moreover, immoderately extend the 

time required for each analysis.

Alternative method. Should it be desirable for any reason to effect 

an actual further separation, this may best be done, up to a certain 

point, after the bisulphate fusion, by removal of the iron by ammonium sulphide in aininoniuin-tartrate solution, evaporation of the 

filtrate, ignition of the residue with sodium carbonate and nitrate, and 

extraction Avith water, whereby titanium and zirconium are left on 

the filter as sodium salts, and the chromium is carried into the filtrate 

as chromate. The further separation of A12O3 and P2O5 from the chromium is outlined under the head of Chromium (p. 51). This is as far 

as the separation can well be carried, and the alumina must still be 

found by subtracting the P2O5 from the combined weights of the A12O3 

and P2O5 . The possibility of loss of some P2O5 by volatilization l during 

the bisulphate fusion must be borne in mind here, for if it takes place 

the final weight of A12O3 and P2O5 will not contain all the P2O5.

Some writers recommend dissolving the ignited alumina, etc., in 

hydrochloric acid, but when the precipitate has been heated over the 

blast, as it should be, this is very ineffective.

MANGANESE, NICKEL, COBALT, COPPER, ZINC.

Ammonia is added to the flask containing manganese, the earths, etc., 

and hydrogen sulphide gas is introduced, whereby manganese, nickel, 

copper, zinc, and a small part of the platinum from the dish are precipitated. The flask is set aside, corked, for at least twelve hours, and

1 G. Rose speaks of such loss when volatilizing sulphuric aoicl in presence of phosphoric acid. 

Handb. f. quant. Anal., Pinkener edition, Vol. II, p. 575, and elsewhere.
42 . ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

preferably twenty-four, or even longer; the precipitate, collected and 

washed on a small filter with water containing ammonium chloride 

and sulphide, is extracted by hydrogen sulphide water acidified with 

one-fifth its volume of hydrochloric acid (sp. gr. 1.11), manganese and 

zinc, if present, going into solution.

Manganese. The filtrate is evaporated to dryness, ammonium salts 

are destroyed by evaporation with a few drops of sodium carbonate 

solution, hydrochloric and a drop of sulphurous acids are added to 

decompose excess of carbonate and to dissolve precipitated manganese, 

and the latter is reprecipitated boiling by sodium carbonate after evap. 

oration of the hydrochloric acid. If zinc is present it can be separated 

from the manganese after weighing. For the small quantities of manganese usually found the sodium carbonate method of precipitation is 

to be preferred to that by bromine or sodium phosphate, as equally 

accurate and a great time saver. No precipitations have as yet been 

made with hydrogen peroxide in alkaline solution, in the manner proposed by Jannasch and Cloedt,1 but the method appears full of promise 

and extremely simple, affording also.separation from zinc, if present, 

and it will be subjected to full trial at some future time.

The employment of ammonium sulphide instead of bromine' for the 

separation of manganese from the alkaline earths and magnesia has 

the advantage that, by a single operation, nickel, copper, and zinc are 

likewise removed if present. There need be no fear of overlooking 

nickel or copper, for under the conditions of the precipitation they are 

not held in solution. Now and then a trace of alumina maybe found in 

the precipitate, and magnesia, too, would contaminate it if ammonium 

salts were not present in sufficient quantity. Begard must therefore be 

had to these possibilities, and also to the rather remote possibility of 

the presence of rare earths which were not thrown out by the basic 

acetate precipitation (see footnote, p. 39).

Nickel, cobalt, copper. 'The paper containing these is incinerated in 

porcelain, dissolved in a few drops of aqua fegia, evaporated with 

hydrochloric acid, the copper and platinum thrown out warm by hydrogen sulphide, and nickel and cobalt thrown down from the ammoniacal 

filtrate by hydrogen sulphide. This is then rendered faintly acid by 

acetic acid and allowed to stand. The sulphide of nickel is simply 

burned and weighed as oxide, its weight being almost always very 

small, and then tested for cobalt in the borax bead.

It is somewhat unsafe to consider traces of copper found at this 

stage to belong to the rock if the evaporations have been conducted, as 

is usually the case, on a copper water bath, or if water has been used 

which has been boiled in a copper kettle, even if tinned inside. Therefore, and because of its contamination by a little platinum, it is better 

to determine copper in a separate portion if its presence is indicated 

with certainty.

1 Zeitschr. fur anorg. Ohemio, Vol. X, p. 405,1895,
DISCUSSION OF METHODS. 43

CALCIUM AND STRONTIUM (BARIUM).

Precipitation and separation. The platinum derived from tbe dish in 

the silica evaporation, except for the small portion precipitated with 

the manganese sulphide, is now wholly in the filtrate from the latter. 

Its filtration at this or any other stage is quite unnecessary; nor is the 

removal of ammonium chloride usually demanded, since there is no 

undue amount present in most cases, the first precipitation of alumina, 

etc., having been by sodium acetate. 1 t Therefore, without destroying 

ammonium sulphide the calcium'and strontium are-thrown out by 

ammonium oxalate at boiling heat, the precipitate, often darkened by 

deposited platinum sulphide, is ignited and redissolved in hydrochloric 

acid, boiled with ammonia to throw out traces of alumina sometimes 

present and reprecipitated as before, but in a small bulk of solution. 

It is weighed as oxide, transferred to a small flask of 20 c. c. capacity, 

dissolved in nitric acid, evaporated to dryness at 150 to 160° C., and 

the separation of strontium from calcium effected by ether-alcohol 2 or 

amyl alcohol.3

Behavior of barium. Barium will, after two ammonium oxalate precipitations, never be found with the ignited calcium and strontium in 

more than spectroscopic traces, unless originally present in excess of 3 

or 4 milligrams, and very often only when in considerable excess.4 If 

present with them, however, it will be separated with the strontium by 

ether-alcohol or amyl alcohol, and these two must then be treated by 

the ammonium chromate method as prescribed by Fresenius,5 in order 

to arrive at the strontium. The barium is best estimated in a separate 

portion, (see Barium, p. 45). .

Necessity of two precipitations ~by ammonium oxalate. It may be said 

with regard to the separation of calcium from magnesium, that two precipitations by ammonium oxalate are essential to the attainment of 

correct results, not only for the complete removal of magnesium, but 

of sodium as well, the retention of compounds of the latter element by 

calcium oxalate having been frequently observed here and elsewhere.

MAGNESIUM. i

Platinum sulphide strongly contaminates the precipitate of magnesium phosphate in the first filtrate from the calcium oxalate, unless 

ammoniacal salts have been removed, as is advisable with very little 

magnesium; but this matters not, as it remains on the filter when the 

phosphate is redissolved in hydrochloric acid and added to the second

'If two or three precipitations by ammonia alone are depended on, the second and third filtrates 

are evaporated rapidly to dryness and the ammonium salts removed by ignition.

*See Fresenius, Zeitschr. fur anal. Chemie, Vol. XXXII, pp. 189, 312, 1893, for the latest improvements in this method. 

"Browning, Am. Jour. Sci., 3d series, Vol. XLIII, pp. 50, 314, 1892.

* W. P. Hillebrand, Jour. Am. Chem. Soc., Vol. XVI, p. 83, 1894; Chemical News, Vol. LXIX, p. 147, 

1894. 

8 Zeitschr. fiir anal. Chemie,Vol. XXIX, p. 428,1890.
44 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

filtrate from calcium oxalate, where it is again precipitated. Barium 

phosphate will not contaminate the second precipitate unless there are 

notable amounts of barium in the rock, in which case it must be 

removed by sulphuric acid prior to the final precipitation of the magnesium. The magnesium-ammonium-phosphate may be collected in a 

Gooch crucible and weighed, or on a paper filter whence it may be 

washed into a tared crucible by nitric acid, evaporated, 1 ignited, and 

weighed therein as pyrophosphate. The latter way, though longer 

than that by the Gooch crucible, offers a certain advantage in facilitating the detection and estimation of the small amount of calcium 

which the magnesium always carries with it (see belqw), but it suffers 

« from an objection which will appear shortly. In order to get the calcium which it carries the ignited pyrophosphate is dissolved in a few 

drops of hydrochloric acid, the solution is rendered just ammoniacal, 

the precipitate just redissolved by acetic acid, a.nd a very small pinch 

of ammonium oxalate is added. In the cold solution, kept down to a 

few cubic centimeters in bulk, a turbidity appears shortly, which is 

almost invariably calcium oxalate, sometimes -accompanied by magnesium oxalate. If necessary, it can be purified by re-solntiou and reprecipitation after ignition, and its weight, averaging one-half milligram, 

is then added to that of the lime already found, and subtracted as 

tricalcium phosphate from that of the magnesium pyrophosphate, in 

order to arrive at the true figure for magnesium. This separation, to 

be successful, must be done with care.

Now it has been often observed that the pyrophosphate obtained by 

evaporation with nitric acid in a platinum crucible does not always dissolve completely in hydrochloric acid after ignition, but that sometimes 

a white residue is left in light lumps which appear to be quite insoluble 

in acids. It contains no silica, but only phosphoric acid and magnesia, 

apparently, and is presumably a peculiar metaphosphate. The cause 

of it's formation is probably this; In the evaporation with nitric acid 

magnesium nitrate and free phosphoric acid are formed, and crystallization partially takes place before the phosphoric acid has had a chance 

to expel the nitric acid, the consequence being that the complete molecular rearrangement, from which only pyrophosphate can result on ignition, can not take place, and the ignition product contains, in addition to 

pyrophosphate, other compounds, including, perhaps, metaphosphate 

and metaphosphoric acid. If the last, the weight found would be in 

error by the water retained by the metaphosphoric acid, even supposing 

none of the latter to be volatilized during ignition. Otherwise the 

weight would not differ from that of pyrophosphate alone. The uncertainty seems to be sufficient to condemn the method for accurate work, 

which is unfortunate, for it obviates the need of dissolving the phosphate

'A pink color of varying intensity almost invariably becomes apparent as the mass approaches dryness, a most delicate test for the traces of manganese which always escape precipitation by ammonium 

sulphide or bromine.
HILLEBRAN ] DISCUSSION OF METHODS. 45

off the felt of the Gooch crucible and subsequent concentration of the 

filtrate in order to look for contaminating lime.

BARIUM AND TITANIUM.

Barium. It has been said above (p. 43) that only in very exceptional 

cases will barium be found with the calcium and strontium after two, 

or possibly three, precipitations of the latter as oxalate, since it passes 

into the filtrates with the magnesium, whence it may be obtained as 

sulphate after removal of ammoniacal salts. Addition of some alcohol 

insures also the recovery of traces of strontium if .the rocks are very 

rich in it. But it is unsafe to regard the amount thus separated from 

the magnesium as representing the total amount of barium in the rock. 

It will almost always be found lower than the truth, probably for the 

reason that there are opportunities during the analysis for slight losses 

in the form of sulphate. It is best to estimate it in a separate portion, 

which may also serve with advantage for the estimation of titanium.

The powder is attacked by hydrofluoric and sulphuric acids, and 

every trace of the former then expelled by repeated, evaporations with 

the latter. This expulsion of fluorine must be thorough, or else the 

titanium result will be low, and it is not always easy to effect this complete removal, though the time required seems to be in no slight degree 

dependent on the nature of the fluorides to be decomposed. Long after 

every trace of fluorine seems to be gone, the formation of a crust on the 

evaporating salts sometimes allows an accumulation of enough hydrofluoric acid gas to become plainly manifest to the smell on breaking 

the crust. Possibly fusion of the mixed sulphates and fluorides with 

boric acid, and removal of the latter by evaporations with methyl alcohol 

saturated with dry hydrochloric acid gas, as recommended by Jannasch 1 

for the conversion of sulphates and possibly fluorides into soluble chlorides, would effect this expulsion of fluorine more certainly than mere 

evaporation with sulphuric acid; but these operations evidently require 

almost constant personal supervision, whereas repeated evaporations 

with sulphuric acid can be carried out on a radiator with almost no 

supervision. Moreover, the barium would have to be reprecipitated, 

whereas by the sulphuric-acid method it is already as sulphate.

The sulphate residue is digested for some time with dilute sulphuric 

.acid of not less than 5 per cent strength. With acid rocks solution is 

very complete, but it can be made nearly so with even the most basic 

by transference to a small beaker and boiling. The filtrate is set aside, 

the residue ignited and fused with sodium carbonate, since zircon, andalusite, and a few other minerals are incompletely decomposed by hydrofluoric acid, and zircon, at least, is often present in appreciable amount. 

The melt is leached with water, washed, and extracted by a few drops 

of dilute hydrochloric acid, from which solution the barium is thrown

. fur anorg. Cbemie, Vol. XII, p. 223, 1896.
46 ANALYSES OF KOCKS AND ANALYTICAL METHODS. [BULL. 148.

out by a large excess of sulphuric acid. A single solution of the barium 

sulphate in concentrated sulphuric acid and reprecipitation by water 

suffices to remove traces of calcium which might contaminate it if the 

rock was one rich in calcium, and even strontium is seldom retained 

by it in quantity sufficient to be concerned about. Should this be the 

case, however, which will occur when the SrO and BaQ are together in 

the rock in, roughly speaking, 0.2 and 0.4 per cent, respectively, the only 

satisfactory way is to convert the sulphates into chlorides and to apply 

to the mixture the ammonium-chrornate method of separation (p. 43).

Barium and strontium sulphates can be brought into a condition for 

testing spectroscopically by reducing for a very few moments the whole 

or part of the precipitate on a platinum wire in the luminous tip of a 

Bunsen burner, and then moistening with hydrochloric acid. This 

should be known to everyone, but probably is not.

The procedure outlined in the foregoing paragraphs for the estimation 

of calcium, strontium, and barium in silicate rocks is the one which long 

experience has shown to be best adapted for securing the most satisfactory results with a minimum expenditure of time. l Even where no attempt is made to separate contaminating traces of SrO and BaO one 

from the other, the error is usually of no great consequence, for an 

absolute error of 25 per cent, even, in a substance constituting only one 

or two tenths per cent of a rock is ordinarily of small moment compared 

with the ability to certify to its presence with approximate correctness.

Separation of barium from calcium and magnesium by the method of 

Mar. With such small amounts of barium as are usually found in 

rocks it is doubtful if Mar's 2 method for the separation of barium from 

calcium and magnesium, by the solvent action of concentrated hydrochloric acid mixed with 10 per cent of ether on the chlorides, could be 

conveniently applied here, although for larger amounts the method 

would seem to be accurate and easily executed. Moreover, it would 

probably not entirely remove contaminating strontium, and hence offers 

no advantage.

Titanium; colorimetric method. The small hydrochloric filtrate from 

the barium sulphate, above mentioned, is evaporated to expulsion of 

the hydrochloric acid and added to the main solution containing the 

titanium, which is then oxidized by fluorine-free hydrogen peroxide3 

and compared with a standard solution of titanium sulphate, similarly 

oxidized (Weller's method).4 Mere traces of hydrofluoric acid render 

the results inaccurate; hence the caution enjoined as to the first treatment of the rock powder and as to the character of the hydrogen 

peroxide, which, as sold in the market, often contains fluorine.

] For details consult ~W. F. Hillebrand, Jour. Am. Chem. Soc., Vol. XVI, p. 83, 1894; Chemical 

News, Vol. LXIX, p. 147, 1894. 

2 Am. Jour. Sci., 3d ser., Vol. XLIII, p. 521,1892.

8 W. F. Hillebrand, Jour. Am. Chem. Soc., Vol. XVII, 1895; Chemical News, Vol. LXXII, p. 158,1895. 

«Ber. Deutsch. chem, Gesell., Vol. XV, p. 2593,1882.
DISCUSSION OF METHODS. 47

Dunnington1 has pointed out the necessity for the presence of at 

least 5 per cent of sulphuric acid in solutions which are to be thus 

tested for titanium, in order, as he concludes, to prevent partial reversion to metatitanic acid, which does not give a color with hydrogen 

peroxide. The standard solution of titanium sulphate holding conveniently about 1 centigram TiO2 in 10 c. c., equivalent to 1 per cent of 

TiO2 in 1 gram of rock, contains, therefore, 5 per cent or more of sulphuric acid. Of this, 10 c. c. are mixed with a sufficiency of hydrogen 

peroxide (2 c. c. of most commercial brands is ample) and diluted to 100 

c. c. in a measuring flask.

The solution to be tested, evaporated if necessary to less than 100 

c. c., is now to be fully oxidized, and if the color is less intense than 

that of the standard, is made up to 100 c. c. with dilute sulphuric acid 

in a measuring flask, and mixed, otherwise in a flask of sufficient size 

to insure that its color shall be less intense. If rectangular cylinders 

are used for comparison, there should be a light box, blackened inside 

and provided with one ground-glass end against which the cylinders 

can be sunk from an opening above, the other end being open for the 

observer to look through. One cylinder being filled with the solution 

to be tested, 10 c. c. of the diluted standard are run into the other from 

a burette, and water is added from a second burette until there is no 

distinction as to color. A second and a third portion of the standard 

can be run in and diluted, and the mean of several determinations 

struck, when a simple calculation gives the percentage of TiO2 in the 

rock.

If the convenient but expensive Soleil-Duboscq colorimeter is used, 

or the simple Nessler tubes, it is of course unnecessary to dilute the 

rock solution to the extent above required, should it be stronger than 

the Standard. Experience has shown, however, that differences can 

not be sharply estimated in strongly colored solutions, and that the 

results are much more satisfactory when the color intensity is not much, 

if any, greater than that given by a standard of the above concentration. For the percentages of titanium found in rocks, clays, and soils, 

usually under 1 per cent, but rising to 2 or even 3 per cent or more 

occasionally, the colorimeter method gives results which are fully equal 

to those of the best gravimetric method, besides being a great time 

saver. The error introduced by iron, in consequence of the yellowish 

color of its sulphate solution, is practically negligible unless its percentage is very high; then either the iron must be removed prior to making 

the color test or, possibly better still, correction should be applied for 

known amounts of ferric sulphate in solutions of the requisite dilution.

The exact correction to be applied in such cases is difficult of determination because of the impossibility of matching the colors of titanium 

peroxide solutions with those of ferric sulphate; but tests made go to

1 Jour. Am. Chem. Soc., Vol. XIII, p. 210,1891.
48 ANALYSES OF ROCKS AND ANALYTICAL METHODS'. [BULL. 148.

show that the coloring effect of 0.1 gram of Fe2O3 in 100 c. c. 5 per cent 

sulphuric acid solution is about equal to 0.2 milligram of TiO2 in 100 c. c. 

when oxidized by hydrogen peroxide. This amounts to a correction of 

only 0.02 per cent on 1 gram of rock containing the unusual amount of 

10 per cent Fe2O3.

Goock's method not readily applicable to rocks containing zirconium. 

Prior to the adoption of this method, the excellent one of Dr. Gooch 1 

was invariably used in this laboratory. Occasional inability.to secure 

clean and complete precipitation by it was experienced, especially with 

a certain series of rocks rather poor in titanium. Long research showed 

the difficulty to be due to the presence of zirconium, which acts as a 

marked preventive of the precipitation of titanium by boiling in an 

acetic acid solution. The above rocks were found to contain up to 0.2 

per cent of ZrO2 , and this amount was able to prevent precipitation of 

0.3 per cent of TiO2 . The titanium which came down in excess of this 

amount did not settle out in flocculent condition, as happens when 

zirconium is not present, and it was difficult to filter. After the removal 

of the zirconium, however, no difficulty was experienced in precipitating all the titanium with the usual ease. In view of the good results 

obtainable by the colorimeter method in the presence, and by the Gooch 

method in the absence, of zirconium, it is incomprehensible that the old 

method of precipitation by many" hours' boiling in a nearly neutral 

sulphate solution in presence of sulphurous acid should still find adherents in any part of the world.

Baskerville's method. Baskerville2 has proposed the separation of titanium from iron and aluminum by boiling the neutralized solution of the 

chlorides for a few minutes in presence of sulphurous acid. The test 

separations, as given by him, are sharp, and a single precipitation is 

said to suffice, the titanium being found free from iron and easily filterable. If it is desired to determine Ti02 gravimetrically, this method 

seems admirably suited. Zirconium would probably be likewise precipitated (seep. 50), and phosphorus, perhaps, also, but this last point 

has not been investigated.

ZIRCONIUM.

This element is rarely looked for by chemists, though shown by the 

microscope to be one of the most constant rock constituents, usually in 

the form of zircon, in which occurrence its amount can be approximately 

judged of and a chemical test rendered almost unnecessary 5 but sometimes it occurs in other minerals, and is then unrecognizable under the 

microscope. It may rarely be present up to a few tenths of 1 per cent 

of the rock.

For its detection and estimation in such cases, or whenever a search 

for it seems called for, the following procedure has been devised, which

JProc. Am.Acad.ArtsSci., n. a., Vol. XII, p. 435; Bull. TT. S. Geol. Survey, No. 27, p. 16,1886; Chemical 

News, Vol. LII, pp. 55 and 68,1885. 

3 Jour. Am. Chem. Soc., Vol. XVI, p. 427,1894.
DISCUSSION OF METHODS. 49

serves, when carried out with care, to detect with certainty the merest 

trace 0.02 per cent, for instance in 1 gram.

The powder is thoroughly fused with sodium carbonate, leached with 

water, the residue dissolved in a little hot dilute sulphuric acid, and 

filtered through the original filter, which is ignited, evaporated with 

hydrofluoric and sulphuric acids, and its solution added to the main 

one after filtration from any barium sulphate that may appear. To the 

solution, which should be in a small flask .and contain not much above 

1 per cent of pure sulphuric acid, is now added hydrogen peroxide to 

oxidize the titanium, and then a few drops of a soluble orthophosphate 

solution. The flask is set aside in the cold for twenty-four to fortyeight hours. If the color bleaches after a time, .more hydrogen peroxide 

should be added. Under these circumstances the zirconium is thrown 

out as phosphate and collects as a flocculent precipitate, which, at this 

stage, is not always pure. No matter how small or insignificant, it is 

collected on a filter, ignited, fused with sodium carbonate, leached with 

water, the filter again ignited, fused with very little acid potassium 

sulphate, brought into solution in hot water with a few drops of dilute 

sulphuric acid, poured into a flask of about 20 c. c. capacity, a few drops 

of hydrogen peroxide and of sodium phosphate added, and the flask set 

aside. Titanium is now almost never present, and the zirconium appears 

after a time as a white flocculent precipitate, which can be collected 

. and weighed as phosphate. For the small amounts usually met with 

it is safe to assume that it.contains 50 per cent of Zr02 (51.8 by theory). 

If the,amount is rather large, it may be fused with sodium carbonate, 

leached, ignited, fused with acid potassium sulphate, reprecipitated by 

ammonia, and weighed as ZrO2. Certainty as to its identity can be had 

by again bringing it into solution, precipitating.by ammonia, dissolving 

in hydrochloric acid, evaporating to a drop or two, and testing with 

turmeric paper. With the very smallest amounts no color can be obtained by this turmeric-paper test, which, however, is readily available 

for as little as 1 milligram ZrO2 , and wi.th the proper care for as small 

. an amount as 0.3 milligram (Dr. H. N. Stokes). J^o element other than 

thorium is ever likely to contaminate the ZrO2 thus precipitated.

This separation of zirconium from titanium in presence of hydrogen 

peroxide is founded .on a method by G-. H. Bailey,1 but in his experiments the precipitation was not made by addition of a phosphate but 

is said to be due solely to the hydrogen peroxide, the precipitate being 

a hydrated peroxide, Zr2O5 or ZrO3 .2 My own efforts to secure a precipitate in acid solutions of zirconium sulphate by hydrogen peroxide alone were unsuccessful, perhaps for lack of a sufficiently strong 

peroxide. The ability to obtain the zirconium free from phosphoric 

acid would certainly be a great improvement on the method described 

above.

1 Jour CLem. Soc., Vol. XLIX, pp. 149, 481, 1886.

2 Bailey, Chemical News, Vol. LX, p. 6,1889:

Bull. 148 4
50 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Were it not for the necessity of working in a much too acid solution, 

the separation of zirconium could be made in the same portion in which 

the titanium is colorimetrically determined.

Davis 1 separates zirconium sharply from aluminum, but not from 

iron, by precipitation as an oxyiodate in a boiling neutralized solution 

of chlorides, but the method is hardly applicable for rock analysis.

Baskerville2 has proposed a method for the separation of zirconium 

from iron and aluminum similar to his method for the separation of 

titanium from those elements (p. 48). It is based on the precipitability 

of ZrO2 by boiling the neutralized chloride solution for two minutes in 

presence of sulphurous acid, and seems to be excellent. As titanium is 

always present and is presumably quantitatively thrown down also, the 

two would have to be separated by hydrogen peroxide. No tests as to 

the availablity of the method for separating the small amounts met 

with in rock analysis have been made.

RARE EARTHS OTHER THAN ZIRCONIA.

For the few cases in which it may be necessary to look for rare 

earths other than zirconia, the following procedure is suggested as 

likely to prove satisfactory in many cases: .

The rock powder is thoroughly decomposed by several partial evaporations with hydrofluoric acid, the fluorides of all earth metals except 

zirconium are collected on a platinum cone, washed with water acidulated by hydrofluoric acid, and the precipitate washed back into the 

dish or crucible and evaporated with enough sulphuric acid to expel 

all fluorine. The filter is burned and added. By careful heating the 

excess of sulphuric acid is removed and the sulphates are taken up by 

dilute hydrochloric acid. The rare earths, with perhaps some alumina, 

are then separated by ammonia, washed, redissolved in hydrochloric 

acid, and evaporated to dryness, then taken up with water and a drop 

of hydrochloric acid, and only enough ammonium acetate to neutralize 

the latter added, followed by oxalic .acid. In this way as little as 0.03 

per cent of rare earths have been found when working on not more than 

2 grams of materials.

This method eliminates at once most of the aluminum, the iron, phosphorus, titanium, and zirconium, and has the further advantage of collecting with the earthy fluorides as UF4 any uranous uranium that the 

rock might have held.

An alternative method would be to fuse with sodium carbonate, leach 

with water to get rid of phosphorus as far as possible, dissolve the 

residue in hydrochloric acid, separate silica as usual, precipitate alumina, etc., by ammonia, dissolve the precipitate again in hydrochloric 

acid, evaporate, and proceed as by the former method, which in most 

cases would undoubtedly give better results than this one.

1 Am. Chem. Jour., Vol. XI, p. 27,1889.

2 Jour. Am. Chem. Soc., Vol. XVI, p. 475, 1894; Chemical News, Vol. LXX, p. 57, 1894.
DISCUSSION OF METHODS. 51 

CHROMIUM, PHOSPHORUS.

Silica is removed by hydrofluoric and sulphuric acids, excess of fluorine expelled, the residue brought into solution as far as possible with 

hydrochloric acid and hot water, filtered, the residue ignited, fused 

with sodium carbonate dissolved in hydrochloric acid, and the solution 

added to the main'one, which is now precipitated by ammonia to get 

rid of the magnesium salts usually present and thus insure a cleaner 

subsequent fusion with sodium carbonate."

Separation of alumina and phosphoric acid. The precipitated A12O3 , 

P2O5 , Cr2O3 , FezOs, and TiO2 is dissolved in hot hydrochloric acid and 

filtered into a large platinum crucible, the filter burned and added, the 

solution evaporated to pastiness, a little water added to dissolve the 

salts, and dry -sodium carbonate added in portions and stirred in thoroughly to prevent lumpiness in the fusion to follow, which is continued 

for half an hour. Addition of sodium nitrate is not necessary. The 

melt is boiled out with water, and to the filtrate containing all the 

chromium and phosphoric acid and most of the aluminum ammonium 

nitrate is added till no further precipitation ensues. All P2O5 is thus 

removed, but not quite all alumina. After decanting, the precipitate 

is washed with ammonium nitrate solution, dissolved in nitric acid, and 

the phosphoric acid thrown out by molybdate solution.

Chromium. The previous filtrate is acidified, boiled, rendered ammoniacal, and hydrogen sulphide introduced or fresh ammonium sulphide 

added., The precipitate of alumina and chromic oxide is now treated 

according to Baubigny, 1 by dissolving in hot nitric acid, evaporating to 

near dryness, and heating with strong nitric acid and potassium chlorate, then evaporating to dryness to get rid of the acid. On dilution 

with cold water, acid sodium carbonate is added in slight excess, and 

after two or three hours the precipitated alumina is filtered off. From 

the filtrate the chromium is then thrown out by fresh ammonium sulphide, redissolved to remove alkali, reprecipitated, and weighed.

Probably the separation of aluminum from chromium by hydrogen 

peroxide in ammoniacal solution, as recommended by Jannasch and 

Cloedt,2 would be preferable to the above if one has specially prepared 

hydrogen peroxide. The commercial brands are so impure that it is 

unsafe to employ them in most separations.

The above outline is from a paper by Dr. Chatard 3 detailing a procedure devised in this laboratory for "-the separation of titanium, 

chromium, aluminum, iron, barium, and phosphoric acid in rock analyses." If necessary, titanium, iron, and barium can be determined in 

the same portion, the reader being referred to the .original paper for 

details.

'Bull. Soc. chimique (N. S.) Vol. XLIJ, p. 291, 1884; Chemical News, Vol. L, p. 18, 1885. 

J Zeitschr. fiir anorg. Chemie, Vol. X, p. 402, 1805.

sAm. Chem. Jour., Vol. XHI, p. 106, 1891; Bull. TJ. S. Geol. Survey No. 78, p. 87; Chemical News, 

Vol. LX.TII, p. 267,1891.
52 ANALYSES OF BOOKS AND ANALYTICAL METHODS. [BULL. 148.

Phosphorus in roclcs' free from chromium. If the rock contains no 

chromium the phosphorus is determined as follows: Fuse with sodium 

carbonate, dissolve in nitric acid, evaporate to dryness, take up with 

nitric acid, filter, ignite filter and treat with hydrofluoric and a drop 

of sulphuric acids, bring the small residue into solution by boiling with 

nitric acid and add to the main portion, in which, after addition of 

ammonium nitrate, precipitate by ammonium inolybdate solution. The 

turbidity often observed on dissolving the precipitated phosphomolybdate in ammonia is due to a compound of phosphorus which should 

always be re-fused with sodium carbonate and treated as above, in order 

to recover the phosphorus in it, if the addition of a small' fragment of 

a crystal of citric or tartaric acid fails to dissolve it.

It is sometimes possible to extract all phosphorus from a rock by 

simple digestion with nitric acid; but quite as often, if not more often, 

this fails, and hence the necessity for resorting to the longer method.

FEKROUS IRON:

Comparison of sealed-tube and hydrofluoric-acid methods* No point in 

rock analysis has been the cause of greater solicitude to the chemist, 

and especially to the mineralogist and petrographer, than the determination of iron in ferrous condition; The sealed-tube method with sulphuric acid, for a long time the only available one, is in theory perfect, 

since complete exclusion of oxygen is easily attainable. Its chief defect, 

however, lies in the inability to always secure complete decomposition 

of the iron-bearing minerals, and even to ascertain, oftentimes, whether 

or not the decomposition has been complete. The addition of hydrofluoric acid to the sulphuric in the tube, in order to insure this breaking 

up, is to be regarded as of very doubtful utility in most cases, since the 

glass may be so strongly attacked as to add an appreciable amount of 

iron to the solution, .and the hydrofluoric acid may have exhausted 

itself in attacking the glass before the more refractory minerals succumb. 

Nevertheless, if decomposition can be effected by sulphuric acid alone 

the results obtained are sharp and concordant, and what is especially 

remarkable, and up to the present without a satisfactory explanation, 

they are in rock analyses invariably higher than when made by any of 

the modifications of the hydrofluoric-acid method now so extensively 

practiced. This difference is not very marked with rocks containing 

but 1 or 2 per cent of .the ferrous iron, but it increases with rising percentage to such an extent that where the sealed-tube method will show 

12 per cent FeO the other may indicate no more than 10 per cent. This 

is a fact of which the writer has long been cognizant, but it does not 

seem to be known to chemists or petrographers at large, and it is one 

well deserving of critical examination. Attempts have from time to 

time been made to get at a solution of the problem, but without effect. 

Experiments with soluble iron salts of known composition, like ferrous 

sulphate or ferrous ammonium sulphate, throw no light on the subject,
DISCUSSION OF METHODS. 53

for both methods give the same sharp and accurate results with them. 

It is only when a silicate is taken that the difference appears. In 

titrating for ferrous iron the well-known rapid bleaching of the first 

permanent color the supposed crucial test of complete oxidation in 

hydrofluoric-acid solutions of silicates, even with sulphuric acid present, has been thought to be perhaps in some way connected therewith. 

This bleaching is so pronounced that several cubic centimeters of permanganate solution may be gradually added after the first so-called 

permanent coloration, without its being possible to obtain a persistent 

color j and yet in hydrofluoric-sulphuric solutions of ferrous salts free 

from silica the first coloration is persistent for a long time.

The question now arises, which of these methods gives the correct 

result. My own opinion is in favor of the sealed-tube method with 

sulphuric acid, simply for the reason that there seems no possible 

chance for obtaining too high results thereby. No suggestion ever 

advanced to account for their being too high seems tenable. It has 

been proved over and over again that the error is not due to iron from 

the glass or to impurities in the sulphuric acid; a reduction of sulphuric acid with corresponding oxidation of ferrous iron seems impossible j and yet, did it occur, the result could be in nowise affected, for 

the amount of permanganate needed would be the same.

Notwithstanding this predilection in favor of the tube method, the 

one in exclusive use in this laboratory is that by decomposition by 

means of hydrofluoric and sulphuric acids. The results obtained by it 

are at least comparable with those found by other workers, and the 

impossibility of being assured of complete decomposition in a sealed 

tube is sufficient to .condemn that method for general use.

Coolers method of decomposing by hydrofluoric and sulphuric acids. 

The specially ground powder, in a capacious crucible, is placed, after 

stirring up with dilute sulphuric acid, on a small water bath of a single 

opening, and covered with a glass funnel whjch rests in a depression of 

the cover, into which water constantly drops from a tubulated bottle, 

thus securing a perfect water joint and serving, to keep the bath full. 

Through a small metal pipe carbonic acid gas flows into the bath above 

the surface of the water, and rising through orifices in the cover fills 

the funnel and crucible.1 The lamp under the bath is lighted and 

hydrofluoric acid is poured into the crucible through a platinum funnel, which is left in place to serve as an occasional stirrer, for which a 

rod or wire maybe substituted. After boiling commences the rapid 

gas current can be safely interrupted, to be restored when the lamp is 

extinguished after one-half to one or more hours. A full stream of cold 

water is then caused to flow from the tubulated bottle into the bath, 

the overflow from the outlet tube being caught in a receiver. As soon 

as cool the contents of the crucible are emptied into a platinum dish 

containing cold water, and titrated till the first permanent color appears

'J. P. Cooke, Am. Jour. Sci., 2d ser., Vol.XLIV, p. 347, 1867.
54 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

which usually will last for only a few seconds. Duplicate determinations are to be advised whenever possible, since even with the utmost 

care the results will occasionally differ more than is allowable.

Pratfs modification of the hydrofluoric acid method. J. H. Pratt 1 has 

shown that very satisfactory ferrous iron determinations can be secured 

by simple boiling of the rock powder with hydrofluoric and sulphuric 

acids in a large crucible fitted with a cover and platinum tube for introduction of carbon dioxide. His test experiments on ferrous sulphate 

show that there need be practically no oxidation, even if the heating 

lasts several hours. The directions given in his paper (p. 150), with 

reference to the treatment of very refractory minerals which are not 

fully decomposed by this treatment, must be understood as referring 

only to homogeneous minerals and not to rocks, where the relations of 

ferrous and ferric iron in the undecomposed portion are certainly different from those in tlie part dissolved.

Influence of sulphides. The presence of pyrite or inarcasite is probably without serious effect on the ferrous-iron determination by any of 

the hydrofluoric acid methods. These sulphides are very resistant 

toward attack in the absence of oxygen, as is shown by the fact that if 

present in any quantity they can be readily recognized in the residue 

after titration.2 In any case, it is impossible to allow for an error introduced by their possible decomposition, and the result of titration must 

count as ferrous iron. In the case of soluble sulphides two sources of 

error are introduced that of reduction of ferric iron by hydrogen sulphide evolved, and that .due to the ferrous iron which the sulphides 

themselves may contain, especially if pyrrhotite is present. The first 

of these is perhaps negligible, since most of the hydrogen sulphide 

would probably be expelled without reducing iron. The second is approximately measurable if it is known that pyrrhotite is the only solu- 

'ble sulphide present and its amount has been ascertained by determining the hydrogen sulphide set free on boiling with hydrochloric acid in 

a current of carbon dioxide. In this case a correction is to be applied 

to the result of titration for total ferrous iron. (See also under Sulphur, p. 59.)

ALKALIES.

The Lawrence Smith method. With the exception of a few determina-. 

tions made in the early days of the Survey's existence, all alkali determinations have been made by the method of J. Lawrence Smith,3 which 

is far more convenient than, and fully as accurate as, the older one, in 

which decomposition is effected by hydrofluoric and sulphuric acids. 

One of its chief advantages is the entire elimination of magnesia at the 

start.

'Am. Jour.'Sci., 3d series, Vol. XLVIII, p. 149,1894. 

2 See footnote, p. 62.

3Am. Jour. Sci., 2d series, Vol. L, p. 269,1871; Am. Chemist, Vol. 1,1871; Annalen Chem. uud Pharm., 

Vol. CLIX, p. 82, 1871.
DISCUSSION OF METHODS. 55

The ammonium chloride used must be purified, preferably by sublimation, or by neutralizing pure ammonia by pure hydrochloric acid, 

and the calcium carbonate is best obtained from pure calcite by solution 

and reprecipitation. However obtained, this lastisnot entirely free from 

alkalies, which must be estimated once for all in order to apply a correction. Eight grams of the carbonate will contain usually from 0.0012 

to 0.0016 grams of alkaline chlorides, almost entirely the sodium salt, 

but the amount has been brought down to half the above by very long 

washing. This correction may be admitted at once to be a defect of 

the method, but it is one easily applied with safety.

The ignition may be made in a covered crucible of ordinary shape 

and of about 20 to 30 cc. capacity, but the heat has to be kept so low in 

this case to avoid loss by volatilization that perfect decomposition is 

not always assured. Hence, to avoid waste of time in very fine grinding, .the form of crucible with cap, originally advocated by Smith, is 

very much to be preferred, since it permits, when set at an angle through 

an opening in the side of a fire-clay cylinder, of the application of the 

full heat of two burners, and perfect decomposition invariably results 

without the need of extraordinary care in grinding. The crucible used 

in this laboratory for one-half gram of rock powder and 4 grams calcium 

carbonate is 8 cm. long, 1.8 cm. wide at the mouth, and 1.5 at the bottom. For double the amounts or more the dimensions are 8 cm., 2.5 

cm., and 2.2 cm. The weights are 25 and 40 grams.

Perfectly satisfactory results are to be obtained with but a half gram 

of rock powder. This is weighed out, ground down somewhat finer in 

a large agate mortar, mixed with its own weight of sublimed ammonium 

chloride, and the two thoroughly ground together. Then nearly all of 

4 grams of calcium carbonate is added and the grinding continued till 

a thorough mixing has resulted. The contents of the mortar are trans-. 

ferred to the long crucible, the rest of the carbonate being used for 

rinsing off mortar and pestle. The crucible is then capped and placed 

in a clay cylinder and heated for about ten minutes by'a low, flat flame 

placed at considerable distance beneath. As soon as the odor of ammonia is no longer perceptible the nearly full flame of two Bunsen burners 

is applied, and continued for forty to fifty minutes. The sintered cake 

detaches readily from the crucible as a rule; if not, it is softened up in 

a few minutes by hot water and digested in a dish until thoroughly 

disintegrated. It is first washed by decantation, and any lumps are 

broken up by a j>estle, then thrown on the filter and well washed with 

hot water. The residue should dissolve completely in hydrochloric acid 

without showing the least trace of unattacked mineral.

The calcium is separated at once by ammonia and ammonium carbonate, and again after evaporation of the filtrate and expulsion of ammonium chloride. The weighed alkaline chlorides should be dissolved in 

water and filtered before addition of platinic chloride, in order to correct 

for the few hundredths of a milligram of fixed residue which is invariably left on the filter.
56 ANALYSES OF EOGKS AND ANALYTICAL METHODS. [BULL. 148.

If the rock contains sulphur this will in part be found with the alkaline chlorides as sulphate. Therefore, if the sulphur is at all considerable in amount it must be removed by barium chloride before the 

second precipitation by ammonium carbonate ; otherwise there is danger of the potassium platinic chloride carrying sodium sulphate. A 

faint reaction for sulphate can usually be obtained, anyway, if the evaporations have been made on a water bath fed by gas.

Lithium. After separation of the potassium platinic chloride, the 

alcoholic filtrate is evaporated and tested spectroscopically for lithium. 

This element is almost invariably present, but almost never in amount 

to warrant quantitative estimation. Should it be so, however, the very 

excellent Gooch method l of separation by amyl alchohol is to be followed, after removal of the platinum by hydrogen gas.2 In rock 

analysis there need be no fear of enough lithium remaining with the 

potassium to cause any concern.

For the most accurate work it is still necessary to look for, and if 

possible estimate, the few hundreths of a milligram of calcium chloride 

that may be with the sodium chloride.

CAKBON DIOXIDE.

For this estimation an apparatus permanently set up is used, of 

which several forms have been described by different writers. The 

rock powder is boiled with dilute hydrochloric acid in a small Erlenmeyer 

flask, attached to an upward-inclined condenser, whence, after passing 

through a compact arrangement of drying tubes -first, one of calcium 

chloride, then one of anhydrous copper sulphate to retain hydrogen 

sulphide from decomposable sulphides and any hydrochloric acid that 

may pass over, and finally a second calcium chloride tube the carbon 

dioxide is retained by absorption tubes filled with soda lime followed 

by calcium chloride. Of course arrangement is made for a current of 

C02-free air with which to sweep out the apparatus before and after 

the experiment,' and for a slow current during its continuance. The 

results are very accurate and the determination can be quickly carried out.

In the preliminary qualitative test for carbon dioxide, it must be 

remembered that while calcite gives off its carbon dioxide on treatment with cold acid, dolomite and siderite do not, and hence warming 

should not 'be omitted; otherwise, a few tenths per cent of carbon 

dioxide can very well be overlooked. Moreover, the powder should 

first be stirred up with a little hot water, to remove all entangled air 

which might otherwise appear to be carbon dioxide.

iProc. Am. Acad. Arts Sci., p. 177, 188C; Bull. IT. S. Geol. Surrey No. 42, p. 73, 1887; Chemical 

' News, Vol. LV, pp. 18, 29, 40,50, 78,1887. «

2 When haste is not an object, this way of removing platinum from the chlorides of the alkalies is by 

far the neatest and most satisfactory. The small flask containing the solution is placed in a water 

bath and attached to a hydrogen generator. After expelling all air the flask is closed, without breaking connection with the generator, and left to itself, except for occasional light shaking up, till reduction is accomplished.
DISCUSSION OF METHODS. 57 

CHLORINE.

To make sure of getting all the chlorine, it is best to fuse with 

chlorine-free sodium-potassium carbonate, or even sodium carbonate 

alone, first over.the full burner, then for a moment or two over the 

blast, leach with water, acidify with nitric acid, and precipitate by 

silver nitrate. If 1 gram of material has been used no precipitation of 

silica need be feared on acidifying or on standing.

In many cases it is quite sufficient to attack the powder by hydrofluoric acid and a little nitric acid, with occasional stirring, and after 

filtering through a large platinum cone, to throw down the chlorine by 

silver nitrate. The presence of nitric acid is necessary, since otherwise 

ferrous fluoride reduces silver nitrate with deposition of crystallized 

silver. When coagulated by heating and stirring, the precipitate is 

collected on the platinum, cone, washed, dissolved by a little ammonia, 

and reprecipitated by nitric acid, when it can be collected in a Gooch 

crucible and weighed, or, if very small in quantity, on a small paper 

filter, which is then dried, wound up in a tared platinum wire, and 

carefully ignited. 'The increased weight of the wire is due to the 

metallic silver of the chloride which has alloyed with it.

FLUO.RINB.

Fluorine can only be estimated by the method of Bose, care being 

taken to use sodium-potassium carbonate as a flux, and to avoid use of 

the blast if possible. The use of ammonium nitrate or chloride instead 

of carbonate for throwing out the silica and alumina is not to be recommended, because of loss of fluorine on evaporation (Eose). If the rocks 

are very basic it may happen that the amount of silica in the alkaline 

solution is so small that ammonium carbonate may be dispensed with 

and the ammonical zinc oxide solution added at once.

By whatever modification of the method the silica may have been 

separated, the alkaline carbonate must be converted into nitrate arid 

not chloride if phosphorus or chromium, or both, are present. To remove 

the chromium and the last of the phosphorus, silver nitrate in excess 

is added to the solution containing still enough alkaline carbonate to 

cause a copious precipitate of silver carbonate, in order to take up the 

acid set free, and thus insure a neutral solution and consequent complete precipitation of phosphorus and chromium. After heating and 

filtering, the excess of silver is to be removed by sodium or potassium 

chloride, and sodium carbonate is to be added, when the fluorine is 

ready to be thrown out by calcium chloride in excess. At this stage 

there must be no ammonical salts in solution, otherwise calcium fluoride may be held in solution.

The well-washed and gently ignited calcium fluoride finally obtained 

in the course of this method should be converted to sulphate as a check 

upon its purity, and at the same time as a qualitative test to ascertain
58 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

if it really is calcium fluoride by the characteristic odor of its gas. 

Should fluorine be found, and the weight of sulphate not correspond 

to that of the fluoride, the former should be dissolved in hot nitric 

acid and tested for phosphorus by ammonium molybdate solution. If 

phosphate is absent the impurity may have been silica or calcium 

silicate which of these it would be difficult to decide. In the former 

case the fluorine might be safely deduced from that of the sulphate, 

but not in the latter! If the rock were rich in sulphur it might happen 

that calcium sulphate would be thrown down with the fluoride, but this 

should be removed by thorough washing. If not, and it were certainly the only impurity present, the fluorine could be calculated, after 

conversion of the fluoride into sulphate, by the formula:

CaSO4 CaF2 : 2 F :: Diff. between impure CaS04 and CaF2 : x.

It is an exceptional case wheu there is exact agreement between the 

weight of fluoride and sulphate, and with the small amounts usually 

met in rocks the error may be an appreciable one in percentage of 

fluorine, though of no great significance otherwise.

There is no qualitative test which will reveal with certainty the presence of fluorine in rocks. Heating the powder before the .blowpipe 

with sodium metaphosphate on a piece of curved platinum foil inserted 

into one end of a glass tube, or in a bulb tube, is not to be relied on 

in all cases. While as little as one-tenth of 1 per cent of fluorine can 

sometimes be thus detected with ease, much larger amounts in' another 

class of rocks may fail to show.

SULPHUE.

If present in the form of soluble sulphates, simple boiling with hydrochloric acid suffices, which should be done in an atmosphere of carbonic 

acid if pyrite or other oxidizable sulphides are present. <

The sulphur of sulphides, chiefly pyritic, may sometimes be determined by extraction with aqua regia or potassium chlorate and hydrochloric acid, but not always ; so that it is better by far to fuse with 

sulphur-free sodium carbonate and a little niter over the Bunsen burner 

and for a few moments over the blast, fitting the crucible into a hole 

in asbestos board to prevent access of sulphur from the flame. The 

aqueous solution, after filtration, is just acidified by hydrochloric acid, 

and the sulphur at once thrown down at boiling heat by barium chloride, without fear of separation of silica in a bulk of about 250 cc. when 

1 gram is operated on. It is well that this is so, for evaporation on the 

water bath heated by gas to remove silica would in many cases involve 

an error fully equal to the sulphur present by contamination from the 

sulphur of the gas burned.

Owing to the small amount of sulphur in rocks, special purification 

of the barium sulphate obtained is hardly ever needful, especially as it 

has been precipitated in absence of iron. Should there be fear of a
DISCUSSION OF METHODS. 59

trace of silica being present, it can be removed by a drop of hydrofluoric 

and sulphuric acids before weighing the barium sulphate.

This, of course, gives the total sulphur in the rock. If soluble sulphates and sulphides as well as insoluble sulphates and sulphides are 

present together, the sulphur of the first is found in solution after 

extraction by hydrochloric acid in a carbon dioxide atmosphere, and 

that of the decomposable sulphides by collecting the hydrogen sulphide 

evolved. In the residue the sulphur of the insoluble sulphides can be 

estimated, or from the total sulphur found in another portion its amount 

can be calculated. The error involved in the above estimation of the 

sulphur of soluble sulphides, due to the possible reducing effect of 

hydrogen sulphide on ferric salts, is probably negligible. Most of the 

hydrogen sulphide would be expelled before any such action could take 

place and probably before the ierric salts were largely attacked, but of 

course the small proportion of sulphur set free as such from pyrrhotite 

would escape estimation and introduce further uncertainty. In general, it would be safe enough to assume the composition Fe 7 S 8 for 

pyrrhotite. However carefully all these separate determinations may 

be carried out, the final figures for ferrous and ferric oxides can hardly 

be regarded as more than approximations when much sulphide is 

present.

BORON.

To the best of the writer's belief it has never been necessary in this 

laboratory to estimate boron in a silicate rock. Should it become 

necessary to do so, since most silico-borates are insoluble minerals, it 

would probably be necessary to fuse with sodium carbonate, extract 

with water, and apply the method of Dr. Gooch,1 depending on expelling the boron as methyl borate by repeated distillations with methyl 

alcohol in nitric or acetic acid solutions, and binding the boric acid by 

a known weight of lime, the gain in weight being B2O3. Fluorine would 

have to be first remove*1 by calcium nitrate or acetate before freeing 

the boron.2

NITROGEN.

Nitrogen has been found in igneous rocks or the minerals occurring 

in them by several observers. Thus, H. Rose 11 says that pitchstone 

gives off arnmoniacal water on heating; Silvestri 4 mentions a nitride 

of iron in lavas from Etna; Sandberger finds ammonium carbonate to 

be given off from certain rocks of Pribram; the writer has shown nitro-

'Proc. Am. Acad. Arts Sci., p. 167, 1886; Bull. II. S. Geol. Survey No. 42, p. 64,1887; Chemical News, 

Vol. LV, p. 7,1887.

' ''For a useful improvement in the way of collecting the boric ether in ammonia before bringing in 

contact with the lime, etc., see Penfleld and Sperry, Am. Jour. Sci., 3d series, Vol. XXXIV, p. 222, 

1887; also Moissan, Comptes rendus, Vol. CXVI, p. 1087, 1893, and Bull. Soc. chimique, Vol. XII, p. 

955, 1894, who modifies the Gooch distilling apparatus and insures complete condensation of the 

boron in the distillate.

3 Quantitative Analyse, p. 673. Mnkener edition.

4 Gazz. chim. ital., Vol. V, p. 303, 1875.
60 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

gen to exist in uraninite; Ramsay and others have noted it in traces 

with or without helium, etc., in numerous minerals; and lately Erdmann l has found it to be given off as ammonia on treating various 

minerals of "ancient igneous rocks" with a caustic alkali. Leudeking 

also found ammonium sulphate in a barite from Missouri, the presence 

of which the writer was able to confirm.

During the last two years it has been noted in this laboratory on 

three separate occasions, when analyzing as many different series of 

ores, roofing slates, and eruptive rocks, that ammonia, either in the 

form of chloride or sulphate or even as free ammonia, was given off on 

heating. Its appearance was not limited to one or a few specimens of 

a series, but seemed to be characteristic of all, and to be afforded by 

the unbroken rock as well as by the powdered sample. Not knowing 

the precise conditions under which the specimens were collected, it is 

impossible to affirm positively that the ammonia may not have 'been 

due to recent organic contamination of some sort, especially in the case 

of the slates, but it is believed that a more critical collection of mate-^ 

rial will not alter the general result. Its amount was sometimes readily 

deterininable by Nesslerization, being as high as 0.04 per cent in some 

slates. Carbonaceous organic matter was absent from most of these, 

but doubtless existed in them in their early history. In their case the 

ammonia was, in part at least, evolved as such, imparting a strong 

alkaline reaction to the water in the upper part of the tube. The presence of sulphides, fluorides, or chlorides in the rock might cause the 

ammonia to appear as a sublimate of sulphate, fluoride, or chloride. 

Speculation on this matter wp.uld be altogether premature, but attention is now called to it in the hope that other observers may be led to 

look for and investigate similar appearances. It should be borne in 

mind that the nitrogen present would not necessarily appear as ammonia or ammonium salts, since it might be given off in the elemental 

condition, as with the gases obtained from uraninite. v

SPECIAL OPERATIONS.

The problem often presents itself of ascertaining the composition of 

that portion of a rock powder which is soluble in special reagents or in 

a reagent of a particular concentration. No precise directions can be 

formulated to meet such cases. The procedure must vary with the 

character of the constituents of the rock and with the object which 

it is sought to attain, and only in exceptional cases can a separation 

of this kind be sharp. Much depends on the degree of fineness of 

the powder and on the length of time it is exposed to the action of 

the reagent.

Detection of nepheline in presence of olimne. For confirmation of the

microscopic diagnosis, Prof. L. Y. Pirsson 2 has indicated a means of

 detecting nepheline in presence of olivine, as in nepheline basalts, based

'Ber. Deutsch. chem. Gesell., Vol. XXIX, p. 1710, 1896. 

3 Am. Jour. Sci., 4th series, Vol. II, p. 142, 1896.
DISCUSSION OF METHODS. 61

on the very ready solubility of nepheline, as compared with olivine, 

when boiled for but one minute with a sufficiency of very dilute nitric 

acid (1:40). Gelatinization of the filtrate on evaporation is taken as 

evidence of the presence of nepheline. If olivine is present in quantity, however, this test must not be accepted at once as final, for some, 

if not* all, olivines are much more soluble in nitric acid of the above 

strength than Professor Pirssou was led to believe froni his original 

tests. If, therefore, on evaporation of the filtrate, much iron is indicated, the gelatinization may well be due to olivine alone or in part, 

and then the quantitative relation of silica to iron plus magnesium 

should be ascertained. It must also be borne in mind that any other 

very soluble silicates present will be more or less affected, and that 

apatite is largely or wholly dissolved. It is possible that still more 

dilute nitric, or perhaps some other, acid may exert a slighter solvent 

action on olivine without being appreciably less effective in dissolving 

nepheline, etc. In combination with a quantitative analysis of the 

extract the method is, perhaps, susceptible of a wider application than 

the particular case for which it was first used. It is well worth further 

study.

Estimation of soluble silica. Very often in treatment by acids silica 

is separated in gelatinous or granular form mixed with the unattacked 

minerals, and it becomes necessary to remove or estimate this silica, or 

else to discriminate between soluble and insoluble silica already existing together. Usually a boiling solution of sodium carbonate has been 

employed for this purpose. Its action is frequently slow and incomplete and the extraction must often be repeated many times as to silica, 

and its solvent action on other minerals is often marked. The filtering 

of hot saturated solutions of the carbonate is also unpleasant. Hence 

the substitution of a caustic hydroxide, as KOH or NaOH, has been 

advocated, especially by Michaelis,1 who maintains with force that 

quartz is absolutely unattacked by boiling 10 per cent solutions (10 per 

cent Na^O), or even by 25 per cent solutions when digested on the 

water bath, and that different results are probably due to the mechanical carrying off in the filtrate of portions of the fine powder, which is 

notoriously difficult to . filter. In the case of separated silica the 

hydroxides certainly give very good results. Solution is almost immediate and complete in a quite dilute liquid, and the difficulty met with 

iu filtering may often be overcome by faintly acidifying. If the dilution is sufficient, no separation of silica results from so doing, and less 

difficulty is experienced in filtering and washing, especially if very 

dilute acid is used for the latter.

ESTIMATION OF MINUTE TRACES OF CERTAIN CONSTITUENTS.

If, as sometimes may happen, the problem is presented of examining 

rocks for traces of gold, silver, and other elements which are not ordi-

»Cbera. Zeitung, Vol. XIX, p. 1422,1895.
62 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

narily looked for, as in Sandberger's investigations bearing on the origin 

of the metalliferous contents of veins, large weights of material must 

be taken, up to 50 grams or more. This involves the use, also, of large 

quantities of reagents, the purity of which must then be looked to with ' 

the utmost care. Special directions to meet such cases can not now be 

given, nor even a complete reference list of the scanty and scattered 

literature on this subject. Sandberger's own writings deal but little 

with its analytical side, and from its inaccessibility in the Washington 

libraries the writer is as yet unacquainted with the report by Von 

Foullon "Ueber den Gang und die Ausfiihrung der chemischen Untersuchung," 1 following Sandberger's own paper,in the general report 

"TJntersuchungen der Nebeugesteine der Pribramer Grange." 2 The 

present writer has published a few data as to gold, silver, lead, zinc, 

etc., 3 in Mr. S. F. Emmons's report on "The Geology and Mining Industry of Leadville;" and Mr. J. S. Curtis,4 in his report on "The SilverLead Deposits of Eureka, Nevada," has given his method of. assaying 

rocks for traces of gold and silver.

PRELIMINARY QUALITATIVE ANALYSIS.

A complete qualitative analysis of a rock, preceding the quantitative 

examination, is in most cases a sheer waste of time. A few constituents may now and then be specially looked for, but in general time is 

saved by assuming the presence of most of them and proceeding on that 

assumption in the quantitative analysis.

SUMMATION OF ANALYTICAL RESULTS.

As is well known, a complete silicate rock analysis which foots up 

less than 100 per cent is generally less satisfactory than one which 

shows a summation somewhat in excess of 100. This is due to several 

causes. Nearly all reagents, however carefully purified, still contain, 

or extract from the vessels used, traces of impurities, which are eventually weighed in part with the constituents of the rock. The dust 

entering an analysis from first to last is very considerable, washings of 

precipitates may be incomplete, and if large filters are used for small 

precipitates the former may easily be insufficiently washed.

Given the purest obtainable reagents, an ample supply of platinum, 

facilities for working, and a reasonably clean laboratory, there is no 

excuse for failure on the part of a competent chemist to reach a sum-

'Jahrbuch der Bergakademie, Leoben u. Pribrani, 1887, p. 363.

Trom Sandberger's report it appears that the rocks were treated successively with water, acetic 

acid, boiling dilute hydrochloric acid for two days, and finally hydrofluoric acid, the several extracts 

and final residue of fluorides (and pyrite) being separately examined for heavy metals. The products 

of distillation were also examined. A'striking fact observed in all cases was the complete insolubility 

of the pyrite, even after the severe treatment mentioned. This speaks strongly in favor of the correctness of ferrous iron estimations in silicates by tho'hydrofluoric and sulphuric acid method when 

pyrite is present unaccompanied by other sulphides. (See p. 54.)

3 Mou. U. S. Geol. Survey, Vol. XII, Appendix B, pp. 592r-596, 1886. 

' «Mon. U. S. Geol. Survey, Vol. VII, pp. 120-138, 1884.
HILLERRAND.J DISCUSSION OF METHODS. 63

mation within the limits 99.75 and 100.50. Failure to attain 100 per 

cent in several of a series of analyses of similar nature should be the 

strongest evidence that something has been overlooked. Excess above 

100.5 per cent should be good ground for repeating portions of the 

analysis in order to ascertain where the error lies, for it is not proper 

to assume that the excess is distributed over all determined constituents. It is quite as likely, in fact more than likely, to affect a single 

determination and one which may be of importance in a critical study 

of the rock from the petrographic side.

QUALITY OF REAGENTS.

It is due to say that all analyses performed in the Survey laboratories have been made with the purest reagents obtainable, either by 

purchase in the open market or by special preparation on the part of 

manufacturers or in the laboratory. The best acids made in this country are of a high grade and need no redistillation except for Special 

experiments. Ammonia has always been redistilled at short intervals; 

and no spdium carbonate which exceeds 2£ milligrams of total impurity 

(see p. 36) in 20 grams (0.012 per cent) is used for the main portions, in 

which silica, alumina, etc., are to be estimated. For other'portions, as 

phosphoric acid, fluorine, sulphur, a poorer grade is entirely allowable, 

provided it is free from the-element to be determined, and from any 

other which might interfere with its estimation.

Hydrofluoric acid was always freshly distilled with potassium permanganate until the introduction of ceresine bottles afforded an article 

sufficiently pure for all but the most exacting work. Care must be 

exercised even yet, however, that no particles of paraffin or ceresine 

are floating on the acid, and that the latter is free from traces of chlorine whenever hydrofluoric acid is to be used for bringing the chlorine 

into solution (p. 57). ' .

Potassium bisulphate has usually been prepared in the laboratory 

from sulphuric acid and potassium sulphate, since it is not always to be 

>bought of satisfactory quality. Even then the normal sulphate had 

first to be examined, for it has been found to contain, on different occasions, notable amounts of lead, calcium, and silica.

The phosphorus salt used for precipitating magnesium has been found 

to contain iron, and calcium is sometimes a constituent of ammonium 

oxalate. The latter has therefore to be purified or specially prepared, 

as also oxalic acid, ammonium chloride (in which latter manganese has 

been observed), and occasionally other reagents. Some hydrogen peroxide contains fluorine, which renders it unfit for use as a chemical 

reagent.

A "C. P." label is no guaranty whatever of the purity of a reagent; 

hence no chemicals should be taken on trust because of bearing such a 

label. Every new purchase should be examined, if it is one in which 

purity is a desideratum. In general all so-called U C. P." chemicals
64 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

should at least stand the tests laid down by Krauch.1 Of late the firm 

of E. Merck in Darmstadt has begun to advertise preparations of a.certain guaranteed purity, thus inaugurating a long-needed reform in this 

direction. Even with them, however, the guaranty should be checked, 

at least until long experience shall have shown the precaution to be 

superfluous.

To his colleague, Dr. H. N. Stokes, who kindly examined the original 

draft of this paper, the writer is indebted for several suggestions which 

have been made free use of in the foregoing.

J Die Priifuug tier chemischen Keagentieii, 3d ed., Berlin, Julius Springer, 1890.
ANALYSES OF ROCKS.

ARRANGED AND TABULATED BY F. W. CLARICE, CHIEF CHEMIST.

IGNEOUS AND CRYSTALLINE ROCKS.

MAINE.

A. Elseolite-syenite from Litchfield. Described by Bayley in Bull. 

Geol. Soc. Ainer., vol. 3, p. 231. Contains elaeolite, two feldspars, and 

lepidomelane, with sodalite, cancrinite, and zircon as accessories. 

Analysis by L. G. Eakins, record No. 1298.

B. Albite from A. Sp. gr. 2.622.

0. Potash-feldspar from. A. v Sp. gr. 2.56. Analyses B and C by 

W. H. Melville, record.Ko. 1275.

SiO, .......................

A13 03

Fe203 ......................

FeO .......................

MnO.... ...................

CaO .......................

MgO. ......................

KaO...... ..................

NaaO. ......................

HgO... .....................

A.

60.39

22.57

.42

2.26

.08

.32

.13

4.77

8.44

.57

99.95

B.

68.28

19.62

.23

.31

.09

3Q

10.81

.09

99.82

C.

65.14

18. 19

.25

.33

.16

14.14

1.68

.17

100. 06

Bull. 148 5
66 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

The minerals found in this rock were quite fully described by Clarke 

in Bull. 42, pp. 28-38. Analyses by F, W. Clarke. 

JD. Elseolite, dark gray. 

E. Hydronephelite. 

F. Lepidomelane. Contains no fluorine.

Si02 .... ....................

AlsOs.... ...................

Fe2O3 ......................

FeO.... ....................

MnO.... ...................

CaO.... ....................

MgO... ....................

K2 0. ..I.... ................

NajO. ......................

H2O... ........ .............

D.

43.74

34.48

4.55

16.62

.86

100. 25

E.

38.99

33.62

.07

1.12

13.07

12.98

99.85

F.

32 09

18.52

19.49

14, 10

1.42

1.01

8.12

1.55

4.62

100. 92

G. Sodalite, deep blue. 

H. Cancrinite, bright orange yellow. 

I. Cancrinite, pale yellow, cleavable. 

J. Cancrinite, pale yellow, granular.

SiO2 .............

A12 03 .. ...........

FeA ............

MnO.............

CaO .............

' MgO.............

KaO. .............

Na.2O. ............

H2 0.... ..........

C03 .. ............

01. ....... ........ .

0 Cl. ..........

G.

37.33

31.87

.10

24. 56

1.07

6.83

101. 76 * 

1.54

100. 22

H.

36 29

30.12

Trace.

Trace.

4.27

.18

19.56

2.98

6.96

100. 36

I.

35.83

29.45

Trace.

5.12

.09

19.33

3.79

6.50

100. 11

J.

37. 22

28.32

Trace.

4.40

.07

.18

19.43

3.86

6.22

99.70
CLARICE AND"] 

H1LLEBKAND.J IGNEOUS AND CRYSTALLINE KOOKS. 67

NEW HAMPSHIRE.

A. EltBolite-syenite from Ked Hill, Moultonboro. Described by 

Bayley in Bull. Greol. Soc. Airier., vol. 3, p. 231. Contains elneolite, 

augite, hornblende, biotite, sodalite, albite, and orthoclase, with accessory apatite, sphene, magnetite, and an occasional zircon. Fibrous 

decomposition products are also present.

B. Mixed albite and orthoclase from A.

C. Nepheline (elseolite) from A. Analyses by W.F.Hillebraud, record 

No. 1321. The mixed nephelhie and feldspar were treated with dilute 

hydrochloric acid, and the residue was extracted with sodium carbonate 

solution. C represents the soluble part, and B the insoluble.

D. Cainptonite from Cainpton Falls. Analysis by L. G. Eakins, 

record No. 1298. Described by J. P. Iddings for the Educational Series. 

Contains hornblende, plagioclase, orthoclase, augite, iron ore, biotite, 

apatite, pyrite, and a mineral which appears to be analcite. Also variable calcite, serpentine, and chlorite.

E. Quartz-porphyry, Pernigewasset. Analysis by Eakins, No. 1298.

Si0.3 ...........

TiOi ...........

Al,03 .. .........

Fe,0;i ..........

FpO

MnO ...........

CaO.... ........

SrO. ...........

BaO.. ..........

MgO... ........

KsO.. ..........

NazO. ..........

Ll,0 ...........

, HaOatlOO0 .....

H2 0 above 100°. 

Po

COS ... .........

A.

59.01

.81

18.18

1.63

3.65

.03

2.40

.08

1.05

5.34

7.03

Trace.

.15

.50 

Trace.

.12

99.98

B.

66.85

19.50

\ »

.11

.07

Trace.

5.80

7.44

.31

100. 21

C.

45.31

32.67

2.00

.16

5.70

12.60

1.56

100. 00

B.

38.45

19.68

4.01

11.15

Trace.

9.37

6.65

1.72

2.77

| 1. 4'9

4.82

100. 11

E.

65.02

17.93

* 4, 69

.17

.11

1.34

1. 24

5. 98

3.04

j .86

100. 38
68 ANALYSES OF ROCKS AND ANALYTICAL METHODS. LuoLL.148.

VERMONT. 

1. BOCKS OF MOUNT ASCUTNEY.

Analyses by W. F. Hillebrand, record Nos. 1621, 1657. Samples 

received from T. A. Jaggar, jr. Petrographic data furnished by 

E. A. Daly.

A. Typical granitite. Contains quartz, orthoclase, plagioclase (microperthite), biotite, magnetite, sphene, apatite, and zircon.

B. Basic segregation in granitite. Contains biotite, hornblende, 

quartz, plagioclase, microperthite, much sphene and apatite, some 

magnetite and zircon.

C. Another sample of B.

D. Syenite. Contains hornblende, augite, orthoclase, microperthite, 

plagioclase, biotite, quartz, magnetite, sphene, apatite, and zircon.

E. Basic segregation in syenite. Contains hornblende, augite, 

microperthite, orthoclase, plagioclase, quartz, magnetite, zircon, and 

apatite.

F. Syenite-porphyry. Contains orthoclase, quartz, hornblende, magnetite, apatite, and zircon.

SiOa.. ........

TiOs ..........

ZrOi.........

AlsOs-.---....

Fe2O3 ........

FeO... .......

MnO. ........

(MCo)O ..... 

 CaO.. ........

BaO.... ......

MgO. ........

K,O. .........

Na2 0. .'.......

HaO at 110° . . 

H2 0 above 110° 

p r>

COa ... .......

F ............

Cl............

FeS2 .........

A.

71.90

.35

.04

14. 12

1.20

.86

.05

Noiie. 

1.13

.04

.33

4.81

4.52

.18 

.42 

.11

.21

.06

.02

100. 35 

.03

100. 32

B.

56.01

1.13

J 15.19

2.34

4.89

.40

.03 

4.85

Trace? ,

4.67

2.16

5.66

.36 

.90 

.53

Undet.

Undet.

Undet.

.09

99.21

C.

59.27

1.12

.04

15.76

2.07

3.57

.37

Trace. 

3.69

Trace?

3.04

q qq

5.63

.23

.74 

.42

.30

- .-42

.03

.07

100. 10 

19

99.91

D.

65.43

.50

.11

16.11

1.15

2.85

.23

? 

1 M

.03

.40

K Q7

5.00

.19 

.39 

.13

Trace?

.08

.05

.07

100. 18 

04.

100. 14

E.

56.51

1.20

.04

16.59

1.35

6.59

.24

Truce? 

4.96

.03

2.52

q f)K

5.15

 ' . 21 

.71 

.41

.33

.24

.07

.06

100. 26 

.11

100. 15

F.

73.03

.30

.06

13.43

.40

1.49

IK

?

79

Trace.

.14

4.54

4.91

.18 

.35 

.06

TVtlPA 1?

.08

.03

09

100. 03 

04.

99.99
CLARKE AND"] 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 69

G. Syenite-porphyry. Coutainsorthoclase,plagioclase,microperthite, 

hornblende, quartz, aug'ite, magnetite, biotite, apatite, and zircon.

H. Granite-porphyry. Composition like D, but with more quartz.

I. Basic segregation in H. Contains hornblende, green and brown 

augite, biotite, quartz, microperthite, magnetite, little apatite, and 

zircon.. . .

J. Diorite. Contains hornblende, augite, biotite, plagioclase, titaniferous magnetite, sphene, zircon, and quartz.

K. Diorite. Composition like J.

L. Another sample of K.

Si0.2 . .........

TiO, .........

ZrOa . ........

A12 03 .........

FesOs ........

FeO... .......

MnO. ........

(NiCo)O ..... 

CaO. .........

BaO. .........

MgO. ........

KaO ..........

Na2 0... ......

H2OatllO°... 

H.;0 above llOc. 

P.2 05 .........

COa-... ......

F ............

Cl ...........

FeS, .........

G.

64.88

.69

.13

16.24

1.37

2.70

.14

None. 

1.92

.06

.89

5.61 .

5.00

.19 

.46 

.13

.08

.04

100. 53 

.04

100. 49

H.

73. 69

.28

.14

12.46

' 1.21

1.75

.15

None. 

.36

.17

4.92

4.47

.14 

.24 

.04

.05

.02

100. 09 

.02

100. 07

I.

56.53

1.40

AQ

. 16. 47

1.58

5.40

OA

Trace. 

4.90

2.67

3.80

K SO

.23 

.60 

.27

.05

.19

.07

99.98 

00

99.89

J.

52.12

2.10

.02

16.35

3.68

6.02

.17

Trace. 

7.25

.04

4.14

2.34

3.65

.25

.88 

89

.07

.03

09

.24

100. 33 

.03

100. 30

K.

57. 97

1.54

J 17.28

2.23

3.75

.15

Trace. 

4,33

.07?

2.20

4.12

4.31

.18 

.57 

.64

.05

.04

Unclet.

.32

99.75 

.02

99. 73

L.

64. 62

.81

.03

16. 46

1.82

2.14

-.12

None. 

2.39

.03

. 1.10

5.21

4.57

.13 

.39 

.21

.11

Unclet.

.05

.19

100. 38 

.01

100. 37
70 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

M. Basic segregation in diorite. Contains hornblende, augite, biotite, 

plagioclase, magnetite, apatite, zircon, and a little quartz.

!N. Diabase. Contains plagioclase, augite, and magnetite.

O. Camptonite. Contains brown hornblende, plagioclase, a little 

augite, olivine, magnetite, and apatite.

P. Phyllite. Contains quartz, sericite, graphite 1?, magnetite, pyrite, 

rare orthoclase, plagioclase, sphene, and rutile.

Q. Microperthite-hornfels. Contains biotite, quartz, red garnet, 

corundum, magnetite, iolite, microperthite, and rarely pleonaste.

E. Cordierite-hornfels. Contains quartz, biotite, pleonaste, corundum, iolite, magnetite, plagioclase, red garnet, and epidotel

SiO, .........

TiO2 .........

ZrO, .........

Al;03 ........

Fe,0;i ........

FeO.... ......

MuO. ........

(NiCo)O ..... 

CaO... .......

BaO .........

MgO.. .......

KaO.. ........

Na.6. ........

H,0 at 110° .. 

H2 0 above 110° 

PS 00 .........

C0.2 . .........

c .............

so3 ..........

Cl ...........

F. ....:......

FeS» .........

M.

55.28

1.64

Trace.

17.23

1.54

6.23

.24

? 

5.60

.06

2.69

2.12

5.42

.20 

.71 

.73

04

.07

.28

.07

100. 15 

.13

100. 02

N.

49.63

1.68

Trace?

14.40

2.85

8.06

.17

.04 

9.28

Trace?

7.25

.70

2.47

.27 

' 1.47 

.25

1.36

None.

.07

Trace.

.22

100. 17 

.02

100. 15

0.

48.22

2.79

.03

14.27

2.46

9.00

.20

.03 

8.45

.04

6.24

1.93

2.90

.28 

1.66. 

.64

1^

None.

.10

.05

.36

99.80 

.04

99.76

p.

90.91

.28

.02

 4. 18

.22

1.27

Trace.

None. 

.22

Trace.

.37

.58

.77

.06 

.74 

.05

.18

.10

Trace.

.11

100. 06

Q.

58.35

.87

21. 30

.03

6.41

.13

.03 

.85

.05

' 2.10

5.63

1.60

.31

0 '.86 

.18

.40

.03.

?

.58

99.71 

\

E.

45.30

1.48

30.51

.24

8.80

.20

. .02 

.90

.03

3.11

4.84

1.65

.26 

1.05 

.12

.17

.04

.04

.04

1.07

99.87

In these rocks the sulphur is all reckoned as pyrite, although pyrrhotite also is probably present. The carbonic acid represents either dolomite or siderite; not calcite. Traces of lithia and strontia occur in 

nearly all. Samples H, L, O, Q contain traces of copper.
CLARKE AND"! 

HILLEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS 

2. MISCELLANEOUS ROCKS.

71

A. Ainphibolite, Guilford. Described by Emerson in Mon. XXIX. 

Contains hornblende needles, with albite and rutile. Analysis by L. G. 

Eakins, record No. 1326.

B. Granitoid gneiss, north of Lincoln's.

C. The-same, west slope of Little Peco.

D. Chloritic granite, Bast Clarendon section.

E. Hornblende-granite, East Clarendon section.

Eocks B? 0, D, E collected by C. L. Whittle, but not described. 

Analyses by H. N. Stokes, record No. 1396.

SiOs ...........

TiOs.. .........

Als08 ... ........

Cr2 03 ..........

FejOa ..........

FeOT.. .........

MiiO.. .........

CaO ...........

BaO. ...........

MgO.........:.

KiO...... ......

NaiO..... ......

H3 0.. ..........

P»06 ...........

A.

49.16

1.03

16.43

3.92

7.19

.23

9.21

.02

8.19

.41

3.70

.45

.16

100. 10

B.

71.02

.35

- 15. 00

1.12

1.81

.31

.69

5.79

2.48

1.14

.13

99.84

C.

69. 97

.44

14.90

2.16

.96

Trace.

.45

.09

.37

6.54

2.85

.66

.12

99.51

D.

67. 3

.80

16.20

1.40

2.73

2.81

.05

' 1.31

2.14

3.15

1.84

.16

99.92

E.

52.60

1.11

18.45

2.47

: "i

.23

7. 55

4, 22

1.12

3.24

2.53

.20

99. 83
72 ANALYSES. OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

MASSACHUSETTS. 

1. ROCKS OF THE CONNECTICUT VALLEY.

Described by Emerson in Mon. XXIX.

A. Serpentine derived from sahlite, Osburn's soapstone quarry, 

Blandford.

B. Dark-green, oily serpentine, center of large Middlefield bed.

G. Enstatite, slightly altered, from Granville. For comparison 

with D.

D. Serpentine derived from enstatite, Granville.

Analyses A, B, 0, by W. P. Hillebrand, record No. 1555. Analysis 

D by Geo. Steiger, No. 1536.

SiOa... ............

Ti02 .............

Ala03 ..... ........

Cr2 03 ........ ....

Fe3 03 ............

FeO.. ............

MnO. ............

NiO. .............

CoO .............

CaO ....'.........

MgO. ...... ......

K2 0... ...........

NaaO.. ...........

Li2 0 .............

H20at 110° ......

H20 above 110°... 

P205 . ............

C0».... ..........

A.

40.77

1.16

.28

3.56

1.47

.09

.17

None.

39.37

.10

.'14

Trace.

.49

12.48 

Trace.

None.

100. 08

B.

38.62

.35

.39

3.44

3.99

.10

.21

.40

40.61

.08

.10

.36

10.91

. .52

100. 08

C.

"li 04.

None.

.52

.14

1.51

3.90

.11

.23

None.

34.40

| .08

.70

3.07

1.32

100. 02

D.

37.82

.61

.19

7.92

1.15

.45.

.05

None.

' 37. 94

I Trace.

7^

12.50 

Trace.

99.38
OLARKE AND"! 

H1LLEBKAND.. IGNEOUS AND CRYSTALLINE ROCKS. 73

E. Eich, dark-green serpentine, from Eowe.

F. Black serpentine containing marinolite, Atwater's quarry, Eussell. 

G-. Blackish-green serpentine containing much chromite. From " The 

Crater," North Blandford. 

H. Gray, splintery serpentine, from Chester. 

Analyses by Steiger, record No. 1536.

SiOB .............

TIG, ..:..........

AljOg.... .........

Cr,0:, ............

Fe.2 03 ............

FeO. .............

MnO. ............

NiO. .............

CoO.... ..........

CaO. ..............

MgO .....:.--....

KjO.... ..........

Na.O.... .........

H2OatlOO°.......

H2 0 above 100°... 

Pf)

C0a .... ..........

S03 ..............

FeS* .............

E.

40.42

1.86

.28

2.75

4.27

.53

.66

35.95

1 IP j .16

.21

10.51

1.44

.43

99.47

F.

36. 94

.50

.33

6.04

1.94

Trace.

.40

None.

38.35

I None.

.71

12.07

1. 85

.20

99.33

G.

39.14

None.

1.18

.33

4.46

3.14

.47

Trace.

41.45

I None. 

.34

9.48 

.02

100. 01

H.

33.87

None.

.77

.28

2.81

4.25

.04

\ »

38.57

I None.

.38

7.00

10.82

.20

99.42
74 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

I. Peridotite, Belcbertown. Contains hornblende, pyroxene, biotite, 

olivine, and magnetite. Analysis by L. G. Eakius, record No. 1326.

J. Massive, coarse, altered diabase, Leverett. Contains saussuritic 

feldspar with black hornblende. Analysis by Eakins, record No. 1325.

K. Tonalite, South Leverett. Dark green, chloritic. Contains reddish feldspar, dark hornblende, and a network of dark-green epidotic 

quartz veins. Analysis by Eakins, record No. 1326.

L. Biotite-granite, Moore's quarry, Florence. Very feldspathic. 

Quartz rare, with fluid inclusions. Feldspar mostly triclinic, orthoclase and microcline present in small quantities. Little nmscovite, 

some rutile. Analysis by Eakins, record No. 1414.

SiOs .........'....

Ti02 .............

AlaOs-. ...........

Crs03 . ............

Fe203 . ............

FeO. .............

MnO...... .......

CaO.... ..........

BaO... ...........

MgO...... .......

KaO. .............

Na.,O. ............

H2 0.... ..........

P806 .... ..........

CO*. ....... ......

I.

48.63

.47

5.32

.36

2.91

3.90

.12

13.04

21.79

.23

.34

2.81

.21

Trace.

100. 13

j.

51.56

1.97

14.82

4.30

7.21

T'fSl f*A

7 OQ

Trace.

7.36

.17

4.21

1.47

.09

100.25

K.

55. 51

.91

16.51

1.68

4.57

 .11

6.73

.02

6.73

2.46

3.19

1.53

.17

100. 12

L.

73.27

.10

15.51

QQ

1.14

2.74

.15

1.66

4.79

fi8

100. 37
CLARKE AND"! 

HU.LEBIIAND.J IGNEOUS AND CRYSTALLINE ROCKS. 75

M. Amphibolite, Bernardston. A black, lieavy, massive hornblende 

rock. Analysis by L. G. Eakins, record No. 1327.

N. Porphyritic amphibolite, Heath. Analysis by Eakins, record 

No. 1325.

O. Amphibolite, New Salera. Analysis by Eakins, record No. 1325.

P. Amphibolite, Whitman's Ferry, Sunderland. Thin, shaly, aphanitic. Analysis by Eakins, record No. 1325.

SiO*..... .........

TiO.2 .............

A12 03 -. ...........

Cra03 ... ..........

Fe203 ............

FeO.. ............

MnO. ............

CaO. .............

BaO. .............

MgO. ............

KaO...... ........

NajO.... .........

HaO...... ........

P,0» .............

C02 ...... ........

M.

51.72

1.39

16.51

1.72

9.56

8.89

6.58

.34

2.74

.51

.23

100.19

N.

51.38

1.07'

18.01

3.30

8.53

.19

6.27

Trace.

5.08

.18

5.34

.56

.18

100.09

0.

45.48

.77

19.43

.13

6.58

10.66

.01

11.08

.11

2.28

3.17

.14

.20

100. 04

P.

49.86

1.58

15. 50

'2.99

8.01

.07

8.89

7.79

.72

3.26

1.51

.11

100.29
76 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Q. Amphibolite, South Leverett. Deep green, ligniform. Analysis 

by L. G. Eakins, record No. 1327.

E. Amphibolite, Goshen. Derived from Conway limestone. Analysis 

by Eakins, record No. 1414.

S. Black, fissile amphibolite, Worthington. Nearly pure, matted 

hornblende. Titanite and sometimes zircon present. Analysis by 

Eakins, record No. 1326.

T. Black, fissile, porphyritic amphibolite, Warwick. Analysis by 

Eakins, record No. 1414. Collected by Emerson, but not described in 

the Monograph.

SiOa.. ............

TiCfe'.. ...........

AJaOa... ..........

Crs03 ............

Fe2 03 .-.--.......

FeO.. ............

MnO-... ..........

CaO...... ........

BaO... ...........

MgO ............. O

K2O. .............

NflaO... ..........

H2O... ...........

P2 06 .............

Q.

47.56

1.24

16.13

1.80

9.39

.08

6.67

9.21

1.58

2.52

3.51

.21

99.90

R.

55.64

.50

16.27

1.22

7.20

.28

9.23

5.58

.19

.91

3.11

.23

100. 36

S.

48.53

.51

16.35

2.03

10.52

.17

9.83

9.71

.32

1.36

.79

.07

100. 19

T.

50.65

.50

13.03

.27

12.67

.15

1.73

16.96

.04

1.37

2.96

100. 33
CLAIIKK AND"] 

HILLEliltAND.J IGNEOUS AND CEYSTALL1NE ROCKS. 77

2. MISCELLANEOUS ROCKS.

Collected by B. K. Emerson and unpublished at the date of writing.

A. Wehrlite, New Braintree. Contains diallage, enstatite, augite, 

anort.hite, biotite, apatite, chromite, magnetite, and pyrrhiotite. Analysis by L. G. Eakins, record No. 1327.

B. Black, serpentinixed boltonite, Stow. Analysis by W. F. Hillebrand, record No. 1555.

C. Highly metamorphosed feldspathic conglomerate, graduating into 

arkose-gneiss. Electric railroad cut, Marlboro. Analysis by George 

Steiger, record No. 1530.

I). Phonolite, Southboro. No description furnished. Analysis by. 

H. N. Stokes, record No. 1653. Contains traces of chlorine and fluorine; 

63.2 per cent of the rock is decomposable by hydrochloric acid.

SiO, .............

TiO, .............

A1803 ............

Cr,03 ............

Fe,03 ............

FeO...... ........

MnO .............

 P'iO

BaO .............

MgO ............. O 

K:-O... ...........

Na2 0. ............

HS 0 at 100°.......

H.2 0 above 100°... 

P2 0ft .............

C08 .. ............

S03... ............

A.

50.64

.82

7.93

.05

1.41

14. 82

.16

3.41

18.58

.21

.96

| .87 

.27

100.13

B.

36.92

None.

.10

1.19

 .87

.59

43.99

| .05

.72

14.70 

Trace.

.90

100. 03

C.

75.35

.21

13. 03

.62

.94

None.

1.33

.07

.21

5.14

2.44

.15

.73 

.08

.03

.03

100. 36

D.

54.22

.38

20.20

2.35

1.02

.19

.70

.29

4.85

9.44

.42

5.57 

.11

99.74
78 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Keratophyr from Marblehead Keck. Described by Sears, in Bull. 

Museum Compar. Zoology, vol. 16, No. 9, p. 170. Contains crystals of 

feldspar, witb a decomposed base, irregular patches of quartz, some 

scales of biotite and grains of magnetite, and also some liinouite and 

earthy matter. The feldspar is anorthoclase. Analyses by T. M. 

Ohatard, record No. 1176.

A. The rock.

B. The separated feldspar.

Sio.,:. ................................

TiO..?. ................. ...... ........

A12O3 .. ...............................

Fe>0, ................................

FeO.. .................... ............

MnO. ................................

CaO .................................

MgO.... .............................

K2O. ........... ......................

"NTn O

PoOfl ...................... ......^....

B,O at 110°...... .I...................

A.

70.23

AQ

15. 00

1.99

Undet.

.24

.33

.38

4.99

A QC

.06

Ql

1.28

100. 42

B.

65.66

Undet.

20.05

Trace.

.13

.67

.18

6.98

6.56

Undet.

.04

.37

100. 64

Feldspars from schists of Berkshire County. Described by Wolff, 

Mon. XXIII, pp. 60 and 187. All albite. Analyses by E. B. Biggs, 

record Nos. 507 and 567.

A. From feldspathic schist, central shaft of the Hoosac Tunnel.

B, C. From the porphyritic mica-schist of Greylock Mountain.

Sioa .... .....:..............

AlaOg.FejOa....... ..........

MuO .......................

CaO........................

MgO.......................

K.O.. .......... ............

Na2 0. ......................

-

A.

69.69

18.60

.20

.40

10.28

.42

99.59

B.

68.08

20.11

?

.36

11.00

.31

99.86

C.

67.83

19.92

?

.25

11.65

.12

99.77

Fe2O3 less than 0.5 in either case.
CLAHKE AND' 

HILLEBKAND.'] IGNEOUS AND CRYSTALLINE ROCKS. 

CONNECTICUT.

79

Basic pitchstone (tachylyte) from the so-called "ash-bed" northeast 

of Meriden. Described by Emerson in Bull. Geol. Soc. Ainer., vol. 8, 

p. 77. Analysis by H. ¥. Stokes, record No. 1641.

SiO'>

TiOs . ..................

Al,0;1 .................

FeO .......'...........

MuO...... ............

PsiO

SrO...................

BaO ..................

MerO...... ............

........... 46i86

........... 1.13

........... 13.96

........... 5.23

........... 4.67

...... .... .Trace.

........... 9. 42

........... .03

........... 7.69

KjO.. ..................

Na2O. ..................

HaOat 110°............

HjO above 110° ........

rr>

F.. .....................

.......... 2.02

.......... 1.85

......... 1.29

.......... 3.43

......... .15

2

-IQ

99.92

NEW YORK.

Peridotite from Dewitt, near Syracuse. Described by Darton and 

Kemp, Amer. Journ. Sci., 3d series, vol. 49, p. 45G. Contains olivine, 

partly serpentinized, biotite, and augite, with magnetite, apatite, and 

perofskite. Possibly a little chromite also. Classed by Kemp as 

limburgite.

Analysis by H. N. Stokes, record No. 1491. The FeO represents 

tbe total iron, because the sulphides present, possibly as pyrrhotite, 

prevent the separate estimation of the two iron oxides.

SiO* ..........

Ti02 .... ......

AlaOs .........

Cr2 03 .........

FeO ..........

NiO...........

MnO..........

BaO ..........

SrO...........

CaO ..........

KaO...........

................... 36.80

................... 1.26-

................... 4.16

................... .20

................... 8.33

09

................... .13

19

................... 8.63

................... 25. 98

................... 2.48

Na 0

H20below'100°.........

H2 0 above 100° .........

PS06 .............'..-..-

so3 .... ................

s ......................

0 8 ...... ............

.......... .17

.......... .51

.......... 6.93

......... .47

.......... 2. 95

.......... .06

......... .95

100. 22

.......... .47

 OQ 7"i
80 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

NEW JERSEY.

Rocks described for the Educational Series, by J. P. Iddings. Analyses by L. G. Eakius, record No. 1299.

A. Basalt, Watchung Mountain, Orange. Contains pyroxene, mostly 

malacolite, plagioclase, magnetite, and glass, with variable amounts of 

serpentine or chlorite. The feldspar is partly altered into a mineral 

which is probably prehnite.

B. Eloeolite-syenite, Beemersville. Contains nephelite, orthoclase, 

segirite, and biotite, with melanite, sphene, apatite, zircon, and magnetite in smaller amounts. Sodalite is probably present also.

C. Minette, Franklin Furnace. Contains alkali-feldspar, biotite, monoclinic pyroxene, magnetite, epidote, calcite, chlorite, apatite, spheue, 

pyrite, and a little secondary quartz.

siOji..-.:.... ...............

AlsOs-.--... ................

Fe.2 0:i ......................

FeO.. ......................

MnO. .......................

NiO.... ....................

CaO. .......................

MgO .......................

KsO.. .......................

Na-sO. ..........'............

H3 0.... ....................

coa ... .....................

A.

51.36

16.25

2.14

8.24

.09

.03

10.27

7 Q7

1.06

i fvi

1.33

100. 28

B.

53.56

24. 43

2.19

1.22

.10

1.24

.31

9.50

6.48

.93

99.96

C.

40.71

19.46

7.46

6.83

.18

11.83

6.21

3.26

1 80

1.53

. 74

100. 01
V.RKE AND"]. 

,LEttIlA.N'IXj

CLARKE 

HILLEUKA.N'IX IGNEOUS AND CRYSTALLINE ROCKS. 

PENNSYLVANIA.

81

A. Aporkyolite, Monterey, Franklin County. Described by Florence 

Bascom for the Educational Series of Eocks. Contains alkali-feldspars, 

quartz, sericite, epidote, titaniferous magnetite, leucoxene, and rarely 

sphene. Analysis by H. 1ST. Stokes, record No. 1479.

B. Quartz-porphyry, same locality. Analyzed for 0. H. Williams, 

but never described. Analysis by L. G. Ealdns, record Fo. 1350.

SiO....... ............................

TiO, .-..........:.....................

AlsOs. .. ...........................

Fe.2 03 :. ..............................

FeO...... ............................

MnO.... .............................

CaO.... ..........-:...-..............

BaO .................................

MgO...... .............. ........:....

KB0.... ..............................

Na.2 0. ................................

H,0at300c ..........................

H.,0 above 100°...... .................

P2 05 .................................

coa ...... ............................

_

A.

.26

11. 60

2.41

.30

.55

.09

.06

2.75

5.50

.10

.39

100. 35

13.

73. 85

13. 15

3.27

.36

.09

.82

.32

5. 42

2.29

} .71

.06

100. 34

Bull.
82 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

DELAWARE.

Feldspars from gabbros. Separated by Diller, described by Chester 

in Bull. 59. Analyses by K. B. Riggs, record Nos. 459, 460, 461.

A. Sp. gr. 2.592 to 2.877j from a typical gabbro. Brandywine Greek, 

Wilmington.

B. Sp. gr. 2.592 to 2.780, from a typical hypersthene-gabbro, found at 

Fifth and Van Buren streets, Wilmington.

0. Sp. gr. 2.592 to 2.749,from " Iron Hill hyperite changing to diorite," 

near "Whitaker's ore pit.

Samples dried at 105°. FeO not determined separately.

SiO.j .......................

A1203 .. ......................

Fe2O3 ......................

MnO.... ...................

CaO... .....................

MgO .......................

KsO.... ....................

NazO...... .................

TTI

A.-

70.37

18.36

.58

.5.08

.04

.63

4.32

.45

99.83

13.

51.44

30.05

.96

13.19

.21

4.07

 .35

100. 27

C.

. 44. 09

35.41

.51

18. 47

Noue.

.19

.99

.35

100.01 ~
CLARKE AND 

HILI.KURAND.. IGNEOUS AND CRYSTALLINE ROCKS. 83 

MARYLAND, INCLUDING THE DISTRICT OF COLUMBIA. 

1. PERIDOTITE AND PYROXENITE.

Described by Williams, Amer. Geologist, vol. 6, p. 35.

A. Porpliyritic Iherzolite, Johnny Cake Eoad, Baltimore Couuty. 

Contains olivine, bronzite, and diallage, the oliviue partly serpentinized. 

Analysis by T. M. Chatard, record No. 1094.

B. Pyroxeuite, Jolmny Cake Road. Consists entirely of hyperstheue 

and diallage.

C,D. Alterations of B. B, C, and D dried at 104°.

E. Smaragdite rock, altered pyroxenite, Dogwood Road, Baltimore 

County.

Analyses B, C, D, E, by J. E. Whitfield, record Nos. 975, 976. C, 

D, and E are from the laboratory record, and do not appear in the 

published paper,

Si02 ...........

TiO, ...........

ALjOs ...'.......

Cr2O:, ..........

Fe,O:i ..........

FeO. ...........

NiO.. ..........

MnO. ..........

CaO ...........

MgO ...........

K.2O... .........

Na^O. ..........

H2 0atll0c ..... 

H3O at red heat.

r,os .. .........

S03 ............

Cl .............

A.

43.87

.12

1.64

.44

8.94

2.60

.19

0.29

27.32

| .50

1.08 

7.64

100. 63

B.

50.80

3.40

.32

1 39

8.11

.17

12.31

22.77

I Trace.

| .52

rPfir» ftf\

.24

100.03

C.

50.10

2.00

.36

2.38

8.68

.29

5.06

 26. 85

I None.

} 4.16

T*VO f*A

.26

100. 14

D.

51. 94

None.

2.53

.60

2.88

9.38

Trace.

3.60

25.97

I None.

| 2.82

1Q '

.16

100. 07

E.

53.22

None.

3.14

.23

7.95

.11

14. 44

' 20. 09

i Trace.

} .98

.26

100. 42
84 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOLL. 148.

F, G. Two samples of websterite, from Hebbville, 6 miles west of 

Baltimore.

H. Bronzite from G.

I. Diopside from G.

The rock consists entirely of bronzite and diopside. Analyses by 

T. M. Chatard, record Nos. 1094, 1123.

J. Cortlandtite from llchester, Howard County. Analysis by W. F. 

Hillebrand, record No. 1422. Published by Williams in 15th Ann., 

p., 674. The rock consists of olivine, pyroxene, and large hornblende 

crystals, the latter considerably altered to talc.

SiO, ...........

Ti02 ...........

A12O:! . ..........

Cr.2 0a ..........

Fe2 0y ..........

FeO.. ..........

MO ............

MuO. ..........

CaO ............

MgO. ..........

K2O ............

Na2 0.. ..........

Li2O ...........

H2 0 at 100° .... 

H2 0 above 100°. 

 P,0fi ...........

F. *

53.98 '

.15

1.32

.53

1.41

3.90

.21

15 .47

22.59

Undet.

Undet.

.09 

.83

100.48

G.

52.55

.14

2.71

.44

1.27

4.90

.24

16.52

20.39

| .27

} 1.09

100. 52

H.

54. 53

Undet.

1.93

.30

1.70

8.92

.28'

2.25

29.51

| 1.14 

Trace.

100.56

i.

51.80

.13

2.21

.51

1.29

3.50

Trace. '

20.99

17.76

Undet.

Undet.

| .65

98.84

j.

39. 20

.52

4.60

.41

3.45

6.15

.30

.20

3.23

31.65

.14

.42

.50 

9.38

100.15
CLAUKE AND"! 

HILLEBRAND.J IGNEOUS. AND CRYSTALLINE ROCKS. 

2. GABBRO AND DIOKITE.

85

Described by Williams, but not in detail, in 15th Ann., pp. 673, 674. 

Some of the rocks, with other analyses, are discussed by him in Bull. 

28. Analyses by W. F. Hillebrand, record No. 1422. .

A. Olivine-gabbro from Orange Grove, Baltimore County. Contains 

plagioclase, diallage, hypersthene, fresh oliviue, magnetite and apatite, and sometimes hornblende.

B. Hypersthene-gabbro, Wetheredville, Baltimore County. Eich in 

hypersthene and diallage, with plagioclase, magnetite, and apatite.

C. Gabbro-diorite, Ilchester, Howard County. A coarse anorthitehornblende rock, probably an altered gabbro.

D. Biotite-diorite, Triadelphia, Montgomery County.

E. Biotite-diorite, Georgetown, D. C.

To these may be added an apparently unpublished analysis made for 

Williams by L. G. Eakins, record No. 1350, as follows:

F. Hornblende-diorite, Rock Creek Tunnel Shaft, Washington, D. C. 

Eelations to E not stated.

SiOs . .........

Ti02 . .........

SnO,,ZrO..?...

AlaO., ........

Cr8 03 ........

PejOa ........

FeO..........

MnO .........

CaO.. ........

MgO.........

K2O. .........

NasO. ........

Li2 0 .........

H2 0 at 100° .. 

H2O above 100° 

P2 05 .........

A.

48.91

.37

8.81

.15

1.04

9.52

.16

14.69

15.19

.10

fi4

.07 

.52

100. 17

B.

44.76

.13

18.82

.08

2.19

4.73

.15

14.58

11.32

.11

.89

.17 

2.36

100. 29

C.

43.42

1.25

22.37

.81

9.25

.06

13.34

5.75'

1.13

1.24

.09, 

1.54 

.10

100. 35

D.

55.97

1.11

15.60

.04

1.21

6.28

.08

7.31

6.83

1 9*1

2.23

.18 

1.85 

.J6

100. 10

E.

56.41

fiq

.14

15.19

OK

1.60

6.24

.11

6.77

7 18

1 <U

2.21

rPf»«1 ftt\

.08 

2.00

fit.

100. 06

F.

56.18

14.76

2.12

6.98

.17

7 Q7

8 11

.80

1 fiO

} 1.37

no

100.16
86 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

3. GRANITE AND GNEISS.

For descriptions see Williams, 15th Ann., p. 657, and Keyes, ibid., 

p. 685. The Rowlandville granite is described by Grimsley in. Journ. 

Cincinnati Soc. $"at. Hist., vol." 17, p. 78.

A. White granite from Brookville, Montgomery County. (Williams.)

B. Binary granite from Guilford, Howard County. Contains quartz, 

orthoclase, a little plagioclase, inuscovite, and biotite, with occasional 

zircon and apatite. (Keyes.)

C. Biotite-granite from Woodstock. Light colored, fine grained. 

Quartz, feldspar, and biotite, with accessory allanite and epidote. 

(Keyes.)

D. Biotite-granite from Rowlandville, Cecil County. Dark colored. 

Contains plagioclase, orthoclase, quartz, epidoto, biotite, sphene, magnetite, and apatite, with a little secondary muscovite. The percentages 

of the several minerals are computed by Grimsley from the analysis.

Analyses by W. F. Hillebraud, record Nos. 1220, 1422, 1455. In B 

and C manganese was present, barium and strontium were not tested 

for, and the alumina contains possible titanium and phosphoric acid.

Si02 ......... ....

TiO« .............

A1,O:! --- ..........

Fe-O:! ............

TVO

MnO .............

CaO .............

SrO. .............

EaO.... ..........

MgO .............

K8 0. .............

Na,0. ............

.Li2 0 .............

H,Oat,100°.......

H2 0 above 100°...

P,0.5 .............

A.

74.87

.05

14.27

Trace.

.51

Trace.

.48

.16

5.36

3.06

.26

.66 

.21

99.89

B.

72.57

Undet.

15.11

.59

1.02

Undet.

1.65

Undet.

Undet.

.30

4.33

3.92

Trace.

| .«

Undet.

99.96

C.

71.79

Undet.

15.00

.77

1.12

Undet.

2.50

Undet.

Undet.

.51

4.75

3.09

Trace.

\ *A

> . 64 

Undet.

100. 17

D.

66.68

.50

14.93

1.58

3.32

.10

4.89

.08

2.19

. 2.05

2.65

.16

1.09 

.10

100. 32
CLARKE AND! 

I1ILLEBUAND.J IGNEOUS AND CRYSTALLINE ROCKS. 87

E. Biotite-grauite from Dorsey's Eun, Howard County. Typical, 

dark colored. Quartz, feldspar, and biotite, with accessory allanite and 

epidote. (Keyes.)

F. Same locality, light-colored dikes.

G. Inclusions in E. Derived from gneiss.

H. The typical gneiss of the Dorsey's Eun area. Perhaps of sedimentary origin.

Descriptions by Keyes. Analyses by Hillebrand. The remarks 

appertaining to B and 0 apply here also. Eecord No. 1220.

SiOs .. ............

Ala03 ... ..........

Fe2O3 ............

FeO.. ............

CaO.. ............

MgO. ............ O

KaO.. ............

NajO. ............

LiaO .............

ii2 o.... ..........

E.

62.91

19.13

.98

3.20

4.28

1.69

3.38

3.94

.63

100. 14

F.

70.45

15.98

.75

1.84

2.60

.77

3.59

3.83

Trace.

.45

100. 26

G.

57.33

15.31

3.39

8.19

3.95

4.36

4.57

1.22

Trace.

1.80

100. 12

JET.

48. 92

16. 57

4.21

9.18

9.69

5.08

1.56

2. 47

Trace.

1.68

100. 26

I. Biotite-granite from Sykesville. Contains quartz, feldspar, and 

biotite, with accessory magnetite, zircon, and apatite.

J. Inclusion in I, derived from limestone. Yellowish central portion. 

Consists of epidote and quartz, woith a little chlorite.

K. Same inclusion, fine-grained dark outer zone. Quartz, garnet, 

and epidote, with a little magnetite. Feldspar and muscovite in some 

portions. Descriptions by Keyes. Analyses by Hillebraud, record No. 

1220, with the same limitations as in the Guilford, Woodstock, and 

Dorsey's Eun granites.

SiOa ... .....................

AlaOs..-. ..................

Fe°2O3 ......................

FeO........................

CaO ........................

MgO.......................

K2 0.. ......................

NaaO. ......................

LiaO .......................

HaO.... ....................

I.

71.45

14.36

2.07

2.78

1.58

1.17

3.28

1.95

r PT*if*n

1.30

99.94

J.

67.02

13.77

4.64

1.02

11.09

.65

.09

.66

1.16

100. 10

K.

47. 35

29.76

2.94

3.15

2.20

1.60

6.83

2.84

3.15

99.82
ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOI.L.HS.

L. Typical gneiss of Washington, D. 0. Quarry of Potomac Stone 

Company, 1 mile below Chain Bridge. A basic granite.

M. Fine-grained, fissile, chloritic gneiss, from northwest of Cabin 

John Bridge. Also a basic granite.

IS". Fine-grained, hard gneiss from the second lock at the Great Falls 

of the Potomac. Probably of sedimentary origin.

Described by Williams. Analyses by Hillebrand, record No. 1459.

Si02 ........'...............

TiOa .... ...................

A1,O3 ...:..................

Fe,03 ......................

FpO

MnO. ...... .................

CaO .......................

SrO...... ..................

BaO .......................

MgO. ......................

KaO...... ..................

Na,0. ......................

Li2 0.... ...................

H2OatllO° ................

H20 above 110°... ..........

PS 0». ......................

L.

67.22

.84

15.34

2.78

3.41

.13

1.36

Trace.

.04

1.65

3.26

2.00

.29

1.68

.14

100. 14

M.

63.43

.91

16. 69

3.36

3.87

.09

.80

Trace.

.03

2.33

3.22

2.38

.23

2.67

.11

100. 12

. N.

78.28

.70'

9.96

1.85

1.78

.08

1 68

Truce.

.02

.95

1.35

2.73

.12

.83

.11

100. 44
1,'LARKE AND") 

H1LLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 89

To these may be added three analyses of feldspars from the pegmatite of Jones Falls, Baltimore. Described by S. L. Powell in Johns 

Hopkins Univ. Circular, vol. 12, p. 49. Analyses by W. F. Hillebrand, 

record No. 1421.

O. Flesh-colored microcline.

P. Green microcliue.

Q. Albite-oligoclase, near Ab4An.

SiOa...... ..................

AlsOs.. .....................

FeaOa...... .................

FeO... ...... ..............

CaO...... ..................

SrO ........................

BaO ........................

MgO .......................

KsO.. ......................

NasO.... ...................

H2O at 100° ................

H2 0 above 100°.... .........

' 0.

65.06

18.41

| Trace.

.26

Trace.

.13

.04

14.30

1.60

.04

.26

100. 10

P.

68.48

16.11

.20

.17

.23

Trace.

OK

.03

12 QQ

1.27

.06

.26

99.85

Q.

63.72

22.26

I Trace.

3.58

Trace.

.06

.76

8.98

OQ

4.3

99.88

P contained a little unseparated quartz. All three contained traces 

of lithia. In O and Q the traces of iron were weighed with the alumina.
90 ANALYSES OF ROGKS AND ANALYTICAL METHODS. [BULL. 148.

4. MISCELLANEOUS ROCKS.

A. Typical diabase, Eocky Eidge. Analyzed for J. S. Diller, but 

not described. Analysis by E. A. Schneider, record No. 1370.

B. Ottrelite-phyllite rock from Liberty, Frederick County. Analyzed for S. H. Williams, but not described.

0. Qttrelite separated from B. Analyses B and C by L. G. Eakins, 

record No. 1349.

D. Quartz-schist, Shoemaker quarry, near Stevenson Station, Green 

Spring Valley. Described by Bayley for the Educational Series of 

>Eocks. Contains quartz, muscov'ite, occasional tourmalines, microclme3 

zircon, and iron stains. Analysis by Schneider, No. 1370.

E. Mica separated from D. Analysis by Schneider, No. 1377.

F. Sericite-schist from Ladiesburg. Described by Bayley for the 

Educational Series. Contains quartz, sericite, chlorite, a mineral 

thought^ to be kaolin, zircon, iron oxide, and rutile. Analysis by 

George Steiger, record No. 1600.

G. Another sample of F. Analysis by Schneider, No. 1370.

SiO, .........

TiO2 .........

AlaOs.. .......

FeaOs 1. ......

FeO. .........

MnO .........

CaO..........

MgO. ........

K2 0..........

Na2 0... ......

LiaO ....... ..

H2OatlOO°...

H30 above 100° 

P206 ... .......

F ............

A.

51.68

.72

15. 87

1.46

8.43

.15

11.08

7.84

.34

1.86

.16

.15 

.12

-99. 86

B.

34.92

3.37

32. 31

10.21

8 dfi

.36

1.13

1.87

2.12

I 5.29 

.23

100. 27

c. ,

23.40

1.19

39.31

5.14

21.94

2.18

.20

.20

-

J 6.81 

Trace.

100. 37

D.

91.65

.13

1.59

3.57

.21

.17

1.93

.07

.60

99.92

E.

44.93

1.05

29/81

i 6.10

1.16

10.28

Kfl

1.38

4.88

.22

100. 31

F. ,

57.24

.08

23.48

3.19

4.8.7

.09

.93

3.55

1 18

.33

4.65 

OQ

99.68

G.

58.11

.81

21.84

2.62

5.63

10

1.85

3.66

Q7

.35

4.05

91

100.29
CLAUKE AND 

HLLLEHRAND.] IGNEOUS AND CRYSTALLINE ROCKS. 

VIRGINIA. "

91

Andesite from 3£ miles east of Front Boyal. Described by Keith in 

14th Ann., p. 305. Intermediate between diabase and quartz-porphyry. 

Contains plagioclase, quartz, magnetite, ilmenite, and a little epidote. 

Analysis by George Steiger, record No. 1450.

SiO, ............................ 51.08

TiOa-........................... 2.67

AL.O:. ........................... 11.37

 Fe,0;1 .'.......................... 11.17

FeO ............................ 5.64

MnO............................ .22

CaO ............................ 5.20

MgO............................ 3.96

K20............................. 1.50

Na,3 0............................ 5.54

H.3OatlOO° ..................... .19

H2 0 above 100°.................. 1.31

P2O6 ............................ .39

100. 24

NORTH CAROLINA. 

1. ROCKS FROM CORUNDUM HILL.

Collected, analyzed, and described by T. M. Chatard, Bull. 42, p, 45.

A. Altered gneiss. Made up of micaceous scales, with grains ot 

quartz and some earthy matter.. Eecord No. 238.

B. Dunite. Olivine rock containing a little chromite. Becord No. 

256.

C, D. Yellow, clay-like alterations of dunite. Becord Nos. 254,255.

Other analyses of altered rocks are given in the paper, and also 

analyses of associated minerals.

Sio/.......:.....

TiO, .............

AlsOa.'.---.. ......

Cr.20;t ............

Fe,03 ............

FeO..............

MnO.............

CaO..............

MgO.............

K20...... ........

Na2 0... ....'......

H20(Ign.) .......

P.,0fi .............

Chromite. ........

A.

64.27

1.32

16.75

6.08

ftl

.07

.25

1.74

3.09

CO

4.97

.05

100. 37

B.

40.11

.88

.18

1.20

6.09

48.58

2.74

.56

100. 34

C.

4:0. 18

1.35

1.41

-in 07

43. 84

2.01

99.76

D.

40. 04

3.17

12.15

42.97

2.14

.17

100. 64-
92 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

2. PYROXENITE FROM WEBSTER.

"Websterite." Described by Williams, Amer. Geologist, v. 6, p. 35. 

Consists of diopside and bronzite. Analysis by E. A. Schneider, record 

No. 1096. Material dried at 105°.

Si02 ............................ 55.14

Ti02 ............................. Trace.

A12O3

FeO. 

MnO 

NiO..

.66

.25

3.48

4.73

.03

.11

MgO....... .................... 26.66

CaO ............................ 8.39

Na3 0............................ .30

HsO............................. .38

P2 05 ............................ .23.

100. 36

KENTUCKY. 

1. THE ELLIOTT COUNTY DIKE.

Described.by Diller in Bull. 38. Also in Amer. Journ. Sci., 3d series, 

v. 32, p. 125.

A peridotite, consisting largely of olivine, sometimes altered to serpentine. Pyrope, ilinenite, a few scales of biotite, a little enstatite, 

and a trace of apatite are present as primary minerals. Secondary 

minerals are serpentine, dolomite, magnetite, and octahedrite.

A granitic rock occurs with the peridotite. It consists chiefly of 

feldspar, orthoclase, and plagioclase, with a considerable amount of 

quartz and ilmenite, and traces of hornblende, sphene, and apatite.

Analyses by T. M. Chatard, record Nos. 272, 273, 282, 305, 351, 352, 

353, 354, and 358.

A. Granite.

B. Peridotite.

0. Olivine from peridotite.

D. Garnet from peridotite.

E. Ilmenite from peridotite. 

The following analyses are of sedimentary rocks adjoining the dike:

F. Calcareous sandstone.

G. Fine-grained fissile sandstone.

H. Indurated shale.

I. Fragment of shale included in the peridotite.
CLARKE AND"! 

HILLEHUAND.J IGNEOUS AND CRYSTALLINE EOCKS. 93

SIC, ...........

TiO, ...........

A13 08 . ..........

Cr,03 ..........

Fe.2 0:i ...... ....

FeO.... ........

MnO ...........

NiO...... .....

CoO. ...........

CaO.. ..........

MgO ...........

KaO.. ...........

Na3 0;.. ........

P2 0S ...........

C03 ... .........

S03 .........---

HoO 110°

H20, ign. .......

A.

60.56

1.19

16.19

5.19

2.41

.36

2.09

1.30

4,82

4.78

.30

.51

99.70

B.

29.81

2.20

2.01

.43

5.16

4.35

.23

.05

7 fiQ

32.41

.20

.11

.35

6.66

.28

} 8.92

100. 86

C.

40. 05

.07

.39

.24

2.36

7.14

.20

1.16

46.68

.21

.08

.04

? '

.14

.66

99.42

D.

41.32

.16

21.21

.91

4.21

7.93

.34

4.94

19.32

.07

\ "

100. 58

E.

.76

49.32

2.84

.74

9.13

27.81

.20

. .23

8.68

\ ,0

Trace.

j .20

100. 10

eSi02 .. ............

Ti02 . .............

AlaOs...... .......

Cr2O3 ............

Fe2O3 ............

FeO..............

MnO.............

OaO .............

MgO..............

K2O.... ..........

NasO.. ...........

P2 06 . ............

COa.... .......... 

H2 0; 110° ........

H2 0,ign .........

F.

60.78

.03

10.54

3.27

.10

10.15

1.59

2.36

1.41

.09

6.29 

.85

2.32

99.78

a.

60.25

.23

20.18

1.53

3.42

.10

.51

3.52

3.17

.39

.10

1.94

5.17

100. 51

H.

41.32

.48

20.71

Trace.

2.59

5.46

.17

9.91

1.91

.88

7.19

.08

.55

8.78

100. 03

I.

35.53

.95

18.23

2.46

4.81

.13

21.17

2.01

1.08

2.53

.08

.88 

1.40

9.00

100. 26

" H" was dried five hours at 110°, previous to analysis.
94 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOLL. 148.

2. THE CRITTENDEN COUNTY DIKE.

A mica-peridotite, described by Diller in Anier. Journ. Sci., 3d series, 

vol. 44, p. 286. Contains biotite, serpentine, and perofskite, with less 

apatite, muscovite, magnetite, calcite, chlorite, and some other secondary products.

A. The rock described by Diller. Analysis by W. F. Hillebrand, 

record No. 1241.

B. An unpublished analysis of probably the same rock, from a shaft 

40 feet deep at Marion. Collected by J. B. Procter, analyzed by L. Gr. 

Eakius, record No. 965.

SiOg. .................................

TiOi .................................

A18 03 . ................................

Cr3O3 ................................

FejOs ................................

FeO.., ........."...........,..........

MnO ..................................

NiO.. ...............................

CoO. .................................

CaO.... ..............................

BaO. .................................

MgO.. ...............................

K,0...... ............................

Ntv,0. ................................

H2O...... ............................

Pa06 ... ...............................

Cl...... ..............................

CO2 ............ ......................

S03 ..................................

A.

33.84 '

3.78

5.88

.18

7.04

5.16

.16

.10

9.46

.06

22.96

2.04

.33

7.50

.89

(ft

.43

99.86

B.

34. 50

14.37

2.85

4.46

11.43

21.81

1.50

.51

7.14

.77

.21

.60

100. 15
CLARKE AND1 

HILLEBHAND. J

IGNEOUS AND CRYSTALLINE ROCKS. 

MISSOURI. 

95

Granite and porphyry, from 6 miles east of Ironton. Described by 

Haworth in Mo. Geol. Survey, vol. 8, Annual Report, pp. 140, 180, and 

213. Analyses by W. H. Melville, record No. 1206.

A, B. Granite.

0, D. Porphyry.

Rocks composed principally of orthoclase and quartz, with some 

microcline, plagioclase, and biotite, and minor accessory minerals.

SiOa. .............

TiOa .............

AljO.-,.... .........

Fe,0a ............

FeO...... ........

NiO. ....... ......

MnO. ............

CaO.... ..........

MgO .............

K^O ...... ........

NajO. ............

HiOatlOO0 ......

H..-0 above 100°...

PaOB . ............

A.

fiQ QA

.25

15.19

1 88

.60

.03

L15

.92

4.29

3.95

.14

.85 

.13

99.32

B.

72.35

.44

13.78

1.87

.36

.20

.06

.87

.42

4.49

4.44

.22

.54 

.13

99.87

C.

71. 33

.55

12.55

3.75

.85

.15

.04

.94

.58

4.20

4.52

.12

.30 

.16

100. 04

D71.88

.22

12.88

3.05

1.05

.02

Trace.

1. 13

.33

4.46

4.21

.17

.26 

.15

99.81
96 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

ARKANSAS.

Ouachitite, from a dike near Maple Spring, 4 miles southwest of Hot 

Springs. Described by Kemp, in Ann. Eep. Geol. Survey Arkansas, 

1890, vol. 2, p. 399. A dike rock of the uiouchiquite group. Contains 

abundant and conspicuous augite and biotite, magnetite, and minor 

accessory minerals in a groundmass considered by Kemp as glass. 

Calcite and other secondary products are also present. According to 

Pirsson, Journ. Geol., vol. 4, p. 679, the so-called "glass" in the inouchlquites is really analcite. Analysis by L. G. Eakins, record No. 1023.

Si02 ............................. 36.40

Ti02 ............................. .42

A1203 ............................ 12.94

Fe203 . ........................... 8.27

FeO. ............................. 4.59

CaO ............................. 14.46

MgO. ............................ 11.44

K2 0.. 

Na^O. 

H2O.. 

P205 . 

CO,..

3.01

.97

2.36

1.04

99.84

TEXAS.

Quartz-pantellarite from the Yieja Mountains, San Carlos, Presidio 

County. Description furnished by E. ,C. E. Lord. Contains anortho 

clase, augite, and grains of quartz in a groundmass of ragtime-augite, 

a brown hornblende, which is probably barkevikite, orthoclase, and 

quartz. Magnetite and apatite are present as accessory minerals. 

Analysis by George Steiger, record No. 1581. .

Si02 ............................ 68.71

Ti02 ............................ .21

A1203 ........................... 13.45

Fe203 ........................... 5.31

FeO............................. .75

MnO............................ .14

CaO ............................ .96

BaO .........................--'. None.

SrO ............................. None.

MgO............................ .19

Ki 0

NaO

Li30 ...................

H2OatlOO° ............

H2 0 above 100° .........

P80» ...................

COs.. ..................

........ 5.51

........ 4.63

........ .13

........ .36

........ .04

........ .05

......... None.

100. 44
CLARKB AND"] 

HILLEBKAND.J IGNEOUS ATCD CRYSTALLINE ROOKS. 97

THE LAKE SUPERIOR REGION. 

1. THE MAKQUETTE AND MICHIG-AMME REGION, MICHIGAN.

Eocks mostly described by Van Hise and Bay ley. When not otherwise specified the descriptions have been published in Mon. XXVIIl, 

and partly in 15th Ann., p. 485. A to E are Huronian volcanics from the 

Michigamme iron district, analyzed by H. 1ST. Stokes, record No. 1C17. 

The hitherto unpublished descriptions of these were furnished by Professor Van Hise.

A. Mica-andesite. Contains plagioclase, biotite with secondary chlorite, iron ore, calcite, epidote, and spheue.

B. Labradorite-porphyrite. Contains plagioclase, epidote, chlorite, 

uralite, titano magnetite, sphene, and calcite.

C. Microphytic amygdaloidal basalt. Contains plagioclase, labradorite, uralite, epidote, chlorite, sphene, and calcite.

D. Spilosite, a contact product of dolerite intrusion. Contains 

quartz, feldspar, chlorite, epidote, and a little biotite.

E. Spilosite. Contains quartz, feldspar, actinolite, and epidote.

SiO, ...........

TiO, ...........

AlaOs.. .........

Cra03 ..........

Fe,03 ..........

FeO...... ......

MnO ...........

CuO ...........

CaO ...........

SrO.... ........

BaO ...........

MgO. ..........

KSO.... ........

Na.2O. ..........

Li,O ...........

H2OafcllO° .... 

H.2O above 110°. 

P,0B ...........

CO.............

SandSOs......

F...... ........

A.

47.20

3.30

15.36

None.

3. 00

8.87

.20

Trace.

5.05

Trace.

4.20

1.40

4.72

.16 

3.04 

.36

3.34

100. 26

R.

52.59

1.36

15. 93

Trace.

6.12

3.96

.25

Trace.

5.04

.67

5.79

.16 2.16' 

*15

99.73

C.

46.47

1.28

16.28

.01

3.15

8.96

.09

Trace.

7.90

6.56

 .21

3.64

Trace.

.28 

3.89 

.13

1.26

100.11

D.

52. 51

1.70

19.00

None.

3.31

7.19

1.55

r Pri PA

3.29

.70

fi 79 '

.34 

3.26

IK

99.72

E.

57.77

.92

19. 35

None.

1.29

3.37

1.71

4.35

.22

8.22

.18 

2.34 

.04

None

99.76

Bull. 148-
98 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Peridotite. Near Opin Lake, E. J sec. 27, T. 48'N., E. 27 W. 

Contains diallage, oliviue, magnetite, and plagioclase. The diallage 

is partly chloritized, and the oli vine is partly serpentinized. Analysis 

by W. F. Hillebraud, record No. 1452.

G. Altered greenstone, Marquette district. Analysis by George 

Steiger, record No. 1580, hitherto unpublished.

H. Griinerite-magnetite-schist, Sec. 11, T. 47 N., E. 27 W. Mainly 

impure griinerite, with magnetite and quartz. Analysis by W. H. 

Melville, record No. 1403.

I. Like H, from sec. 18, T. 47 N., E. 28 W. Analysis by Melville, 

record No. 1403.

J. Like H and I, froin sec. 20, T. 46 N., E. 30 W. Analysis by H. N. 

Stokes, record No. 1546. H, I, and J are similar schists, and alike in 

mineralogical composition.

Si02 . ...........

TiO, ...........

AlaO-,. ..........

Cra O:, ...........

Fe2 0;! ..........

FeO ...........

MnO ...........

MO... .........

 CuO ...........

CaO. ...........

SrO. .......... i

BaO ...........

MgO ...........

K2 0.... ........

Na2 0.... .......

H2 0 at 110- ....

IliO above 110°. 

.P8 06 ...........

CO.............

SO..............

F.

39.37

.66

4.47

68

4.96

9.13

.12

.21

3.70

T^TH PP

26. 53

.26

.50

.87

7.08 

.17

1.23

99.94

G.

48.85'

1.28

15.83

2.50

10.79

.11

6.20

09

None.

5.82

1.31

2.79

.27

3.77 

.22

None. '

.06

99.89

H.

46.94

1 .66

4.51-

33. 72 .

.31

3.22

6.64

.16

J .67 

.07

2.79

99.69

I.

49.70

1.35

3.10

37.19

.93

.68

5.72

Trace.

J 1.40 

.12

100.19

J.

46. 25

.92

30.62

16.92

1.01

None.

Trace.

1.69

None.

2.13

None.

.42 

.07

None.

100. 03
CLARKK AND"! 

HILLBBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 99

K. Green schist, from sec. 34, T. 48 N., E. 27 W. Near center of section. Contains plagioclase, chlorite, and quartz. Analysis by George 

SSteiger, record No. 1447.

L. Sericite-schist associated with the preceding. Mainly sericite and 

quartz. Analysis by Steiger, No. 1447.

M. Dark-gray, foliated schist. SE. corner of sec. 30, T. 47 N., E. 

30 W. Contains quartz, plagioclase, orthoclase, and biotite. Analysis 

by Steiger, No. 1525.

"N. Schistose gneiss. NW. £ of sec. 35, T. 47 N., E. 26 W. Contains 

quartz, kaolin, sericite, plagioclase, chlorite, magnetite, and-apatite. 

Analysis by Steiger, No. 1525.

O. Novaculite from Marquette. Described by Williams in Bull. 02. 

Contains quartz and sericite. Analysis by W. F. Hillebrand, record 

No. 759.

SiO2 .. ..........

TiOa ...........

AU03 - ..........

Fe,0;( ..........

FeO...... ......

MnO ............

CaO.- ..........

MgO ........... O

KaO. .-.-.:.-...

NajO. ..........

LioO ...........

H,O at 100° .... 

H20 above 100°. 

P8 0fi ...........

CO3 .. ..........

K.

61.35

' .26

16.45

.94

4.20

3.46

3.12

1.05

5.24

.10 

2.51 

.18

1.98

100. 84

L.

70.76

.33

. 14. 83

1.46

3.09

.36

1.99

3.50

.47

.09 

2.70 

.26

99.84

M.

63.50

.62

17.89

1.12

 5.38

2.34

1.22

2.43

2.55

.22 

2.04 

.19

99.50

N.

82.38

.14

11.32

.97

.26

.22

.17

1.04

.59

.18 

2.33 

.09

99.69

0.

76.99

13.92

.45

.77

.32

1.12

3.65

.56

Trace.

| 2.35

100. 13
100 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOLL. 148.

2. THE MENOMINEE KIVEK.

1ST. THE STURGEON FALLS GABBRO.

From Sturgeon Falls, Menominee Eiver, sec. 27, T. 39 N., K. 29 W., 

Michigan. Described by Williams, Bull. 62, p. 67.

A. Saussurite gabbro. Contains plagioclase, almost wholly altered 

to saussurite, diallage, hornblende, and ilmeuite, with quartz, calcite, 

and chlorite as alteration products.

B. The same, altered and somewhat schistose. Feldspar much 

altered into, calcite, with secondary quartz and sericite: pyroxene and 

hornblende changed to chlorite. Leucoxene common.

C. Light-gray, silvery schist, derived from gabbro. Contains chlorite, calcite, and a little quartz, with remnants of feldspar and some 

leucoxene. Analyses by R. B. Riggs, record Isfos. 389, 390, 391. Material dried at 105°. TiO2 undetermined.

SiO2 .......................

AlsOs ....... ....... ......

FesOa ......................

FeO.... ....................

CaO .......................

MgO. ......................

KaO... .....................

N^O. ......................

cos .. ......................

H,0.... ....................

A.

51.46

14.35

3.90

5.28

9.08

9.54

.24

2.92

.20

3.30

100.27

B.

38.05

24. 73

5.65

6.08

1.25

11.58

1.94

, 2.54

.93

7.53

100.28

c.

45. 70

16.53

4.63

3.89

4.28

9.57*

3.82

 .55

5.95

4.70

99.62
CLARKE ANDT 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 101

2D. LOWER QUINNESEC FALLS, MENOM1NEE RIVER.

Described by Williams, Bull. 62, pp. 89, 91.

A. Gabbro-diorite, shore below falls, Wisconsin side. Contains saussurite, hornblende, and ilineuite. Some calcite in the saussurite. Hornblende partly altered to chlorite and ilmenite to leucoxene.

B. The same, schistose form. Contains less saussurite. Hornblende 

and ilmenite completely altered into chlorite and leucoxene. Calcite 

present, and also porphyritic feldspar.

C. Silvery schist, adjoining B. and derived from gabbro. Eesembles 

B in general, without the feldspar crystals. Calcite and sericite are 

present, and rutile in place of leucoxene.

D. Dark, massive greenstone. Contains hornblende, chlorite, epidote, quartz, leucoxene, with some ilmenite and traces of original 

feldspar.

B. Dark, schistose greenstone, forming a band in D. Chlorite entirely 

replaces hornblende, and rutile replaces leucoxene. Some feldspar, 

quartz, and calcite.

Analyses by E. B. Eiggs, record Nos. 384,385,380,387,388. Material 

dried at 105°.

Si O2 ...- ........

AlsOs... ........

Fe203 ..........

FeO.... ........

CaO. ...........

MgO. ..........

KjO. ....... ....

Na2O. ..........

COS . .. .........

HsO...... ......

A.

47.96

16.85

4.33

4.17

13.25

Q 15

.30

1.25

.08

2.89

100. 23

B.

49.19

18.71

5.03

4.04

5.92

7.98

.77

1.44

1.82

5.05

99. 95

C.

46.21

18.38

3.30

3.90

6.28

7 03

.35

2.14

8.32

3.82

99.73

13.

43. 80

16.08

9.47

10.50

7.81

6.54

.34

1.96

.08

3.99

100. 57

E.

44.49

16.37

5.07

5.50

7.94

7.50

.56

2.59

5. 38

4.99

100. 39
102 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

3D. UPPER QUINNHSEC FALLS, MENOMINEE RIVER.

Described by Williams, Bull. 62, pp. 104, 113,114, 121.

A. Light greenstone. Contains hornblende, feldspar much altered 

to saussurite, ilmenite with leucoxene border, and some secondary 

quartz.

B. Mica-diorite-porphyry. Mainly andesitic feldspar and biotite, 

with apatite, zircon, sp'hene, and some calcite.

C. Biotite-gneiss from Michigan side. Contains biotite, soda-orthoclase, and quartz. Sphene common, zircon and apatite present.

D. Schistose quartz-porphyry. Contains quartz, feldspar, sericite, 

some chlorite, anatase, and tourmaline, with zircou and apatite sparingly.

A, B, and D are from the Wisconsin side of the river.

Analyses by E. B. Eiggs, record Nos. 392, 393, 394, 395. Material 

dried at 105°.

SiO-2 ..............

A.13 03 .. ........... 

Fe*03 ............

FeO

CaO... ...........

MgO.... .........

K«0.. ............

NajO. ............

CO,.... ..........

H2O. .............

A.

48.35

15. 40 

4.04

4,63

10.38

11.61

' .35

1.87

.08

3.60

100. 31

B.

54.83

25.49 

1.61

1.65

6.08

1..96

1.87

5.69

.18

1.18

100.54

C.

67.77

16.61 

2.06

1.96

1.87

1.26

2.35

4.35

1Q

1 fiQ

100. 11

D.

66.69

16.69 

2.06

.93

1. 40

1 1^

K OQ

2.46

1.42

1.70

99.73
CLARKE AND"! 

H1LLEBBANU.J IGNEOUS AND CRYSTALLINE ROCKS. 

3. THE PENOKEE-GOGEBIC REGION.

103

Kocks mostly described by Van Hise in Mon. XIX. Analyses A to G 

by T. M. Ohatard, record Nos. 991, 992, 993, 994, 995.

A. Diabase from near SE. corner of sec. 13, T. 47 N., E. 40 W.; Michigan. Contains plagioclase, augite, magnetite, apatite, and oliviue, 

with some ilmenite and leucoxene.

B. Same dike as A, partly altered. The pyroxene is altered to 

amphibole, and the latter partly to biotite. Biotite has also been 

derived from feldspar.

C. Feldspar separated from A.

D. Altered diabase from the Aurora mine, NE. J of SW. J of T. 47 

N., E. 47 W., Michigan.

SiO2 .............

TiOa .............

AV)3 . ............

CreOs ............

Fe,03 ............

FeO.. ............

MnO. ............

NiO. .............

CaO .............

BaO .............

MgO. ............

K,0...... ........

Na,0. ............

1-1,0 at 105° ......

H,0 above 105°. .. 

P..CV, .............

CO....... ........

. A.

47.90

.82

15.60

Trace.

3.69

8.41

.17

.10

9.99

.05

8.11

.23

2.05

.15

2.34 

.13

.38

100. 12

B.

46.85

1.12

22.62

5.12

 1.58

2.54

.08

1.25

.10

2.01

2.66

.80

3.12

8.25 

.16

1.89

100. 15

/ c.

51. 18

27.00

3.19

Undet.

.17

11.70

1.92

.41

3.48

] 1.19

100.24

D.

41. 60

3.79

37. 20

3.21

.30

.08

'.23

.02

.07

.29

13.54 

.14

.38

100. 85
104 ANALYSES OF EOCKS AND ANALYTICAL METHODS. [BULL. 148.

E. Feldspar separated from gabbro j southern half of sec. 14, T. 44 N., 

E. 4 W., Wisconsin.

F, Gr. Feldspars separated from divine-diabase; NE. £ of sec. 13, 

T. 45 N., E. 1 W., Wisconsin.

SiOa.... ....................

Al,0;( ... ....................

Fez03 .......................

FeO.... ............ ........

MnO .......................

CaO .......................

MgO.. .............. .......

K8O...... ..................

NajO.. .....................

H2Oatl05° ................

H2O above 105°...... .......

E.

51.99

29.32

i 1.23

12.60

,63

.28

2.91

.03

.54

99.53

p.

61.65

19.91

2.28

Undet.

Trace.

4.12

.61

5.72

.4.74

| .95

99.98

G.

56.15

26.05

1.98

Undet.

.13

8.70

.54

1.50

4.79

.13

.64

100. 67
CLARK E AND"1 

HILLKBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 105

The following analyses, by W. F. Hillebraud, of separations from 

the gabbro of Ashland County, Wisconsin, were made for the late E. D. 

Irving, but were never published by him:

H. Magnetite, record No. 637. Partial analysis.

I. Feldspar, record No. G88.

J. Diallage, record No. 686.

For convenience I also include here, although it is decidedly out of 

classification 

K. Graywacke, Hurley, Wisconsin. Collected for the Educational 

Series of Eocks. Analysis by H. N. Stokes, record No. 1314. Examined by W. S. Bayley. Contains quartz, feldspars, iron oxides, and 

probably kaolin. In the cement are chlorite, quartz, magnetite, pyrite, 

rutile, occasionally biotite, and either muscovite or kaolin.

'

Si02 .............

Ti02 .............

A12 03 ............

Fe203 ............

FeO.. ............

'MnO. ............

CaO .............

SrO. .............

BaO .............

MgO. ............

KaO...... ........

Wa3 0 ............

LiaO. ............

HsO... ...........

P206 .............

H.

8.77

50.29

30.70

89.46

I.

53.30

29.03

.55

.23

11.40

.13

.40

4.87

.23

T^TO PA

100. 14

J.

49.80

1.29

2.86

2.48

10.82 '

.37

16.50

15.33

.12

K1

Trapp?

.33

Trace.

100.41

K.

76.84

11.76

2.88

.70

1.39

'1.62

2.57

1.87

100. 18
106 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BDLL.HS.

4.' ROCKS OF PIGEON POINT, MINNESOTA.

Described by Bayley in Bull. 109. Also partially in Amer. Journ. 

Sci., 3d series, v. 37, p. 54.

A. Olivine-gabbro. Contains labradorite, olivine, pyroxene, apatite, 

and magnetite. Analysis by W. F. Hillebrand, record No. 496.

B. Diallage separated from gabbro. Partial analysis by B. -B. Biggs, 

record No. 607. " 

C. Bock lying between the gabbro and the adjacent red porphyry. 

Contains red feldspar, quartz, hornblende, chlorite, magnetite, apatite, 

and rutile. Analysis by W. F. Hillebrand, record No. 500.

SiO2 ........... ...... ......

TiO2 .......................

ZrO2 . ...... ................

A12O3 . ......................

Te2 03 ......................

FeO-... ....................

MnO...... .................

CaO...... ..................

SrO...... ...................

BaO .......................

MgO. ...................... O

KgO. ....................

NaaO.... ...................

Li2 0'.. ................ i....

H20. .......................

P

/i

Pi

A.

49. 88

1.19

18.55

2.06

8.37

.09

9.72

Trace.

.02

5.77

fi8

2.59

1.04

.16

Trace.

100.12

B.

48.34

1.98

2.90

4.68

14.15

15.10

11.34

98.49

C.

57.98

1.75

13.58

3.11

8.68

.13

2.01

Trace.

.04

2.87

3.44

3.56

2.47

.29

Trace.

99.91
CLAKKE AND"] 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS'. 107

D. Bed soda-granite. Contains feldspar, quartz, chlorite, some muscovite, rutile, leucoxene, hematite and apatite, -with sometimes secondary calcite. Granular variety. Analysis by W. F. Hillebrand, record 

No. 495. Dried at 110°.

E. Same as D, porphyritic variety. Called by Bayley a quartzkeratophyre. Analysis by Hillebrand, record No. 497.

F. Similar red porphyry from Little Brick Island, Lake Superior^ 

near Pigeon Point. Consists chiefly of feldspar and quartz, with augite 

occasionally present. Analysis by L. G. Eakiiis, record No. 1059.

G. Red feldspar, anorthoclase, separated from 'D. Contains hematite inclusions. Analysis by J. E. Whitfield, record No. 521. Dried 

at 104°.

SiO,. .............

TiOo .............

ALO.,. ............

Fe.O:, ............

FeO.. ............

MnO .............

CaO .............

Sr'O. .............

BaO ..............

MgO. ............

1^0 ..............

Na.,0. ............

Li,O .............

HoO... ...........

P,06 .............

Cl... .............

D.

72.42

.40

- 13.04

.68

2.49

09

.66

Trace?

.15

.58

4.97

3.44

Trace?

1.21

.20

Trace.

100. 33

E.

74.00

.34

12.04

.78

2.61

.05

.85

.12

.42

4.33

3.47

Trace?

.86

.06

99.93

F.

73. 70

.12

12.87

3.76

.31

.07

.14

.11

4. 56

3.63

.57

99. 84

Gr.

65.00

18.22

2. 64

1.06

.06

4.18

8.40

.46

100. 02
108 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

H. Dark vitreous quartzite. Contains quartz, a little red feldspar, 

some chlprite, some green mica, a few scales of biotite, and grains of 

magnetite.

I. Lighter interbedded quartzite. Feldspar in it much altered.

J. Epidotic quartzite.

K. Unaltered quartzite.

Analyses by E.. B. Riggs, record JSTos. 569, 571, 572, 575. Material 

dried at 105°. Ba and Sr not looked for.

Si0.2 .............

TiO* .............

Al,0a .. ...........

Fe,0:! ............

FeO. ..............

MnO. ............

CaO .............

MgO. ............

KaO.. ............

Na,O. ............

Ign ..............

H.

74.22

.16

10.61

7.45

.85

.56

1.48'

1.08

2.12

1.79

100. 32

1.

73. 65

Trace ?

11.08

7.24

.77

.40

1.52

1.65

1.67

1.88

99.86

J.

73.14

.04

12.60

7.57

i 31

.43

1..67

1.00

1.78

.83

100. 37

1C.

73.64

11.25

6.24

1.04

.36

1.57

1.42

3.04

1.98

ICO. 54
CIAHKE A NUT 

HLLLEliliAND.J IGNEOUS AND CRYSTALLINE ROCKS. 109

L. Altered quartzite. Contains more fibrous chlorite, some sericite,- 

a little kaolin andbiotite, grains of magnetite, earthy matter, and sometimes a little calcite. Analysis by E. B. Riggs, record No. 570. 

' M. Mottled quartzite. Analysis by Riggs, record No. 573.

N. Purplish slate, containing many small crystals of red feldspar and 

scales of mica. Analysis by J. E. Whitfield, record No. 520.

O. Very slightly altered slate. Analysis by Riggs, record No. 576.

Material for analysis dried at 104°-105°.

Ba and Sr not looked for.

SiO3 ... ..........

TiO. .............

AljOs.. ...........

Fe.2 03 ............

FeO... ...........

MnO...... .......

CaO.. ............

MgO. ............

KsO. .............

Na20. ......'......

Li2 0 .............

H2 0. .............

P206 .............

S03 -.........'....

L.

71.00

.44

12.88

6.69

.65

.21

1.68

2.95

1.43

2

AO

99.96

M.

7'2. 25

Trace.

10.73

8.01

.38

.42

1.85

2.56

2.03

2.05

100. 28

N.

63.82

2.66

14.65

3.16

5.12

.70

2.08

2.81

1.95

2.62

.19

.33

100. 09

0.

59.71

Trace.

18.32

8.11

.85

ATr\Tl A

1.05

3.54

3.43

1.93

3 OA

100. 18
110 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOLL. 148.

- P. Bed granitic rock resembling D, but with more dark spots, found 

in contact with the purplish slate, N. Consists mainly of red feldspar, 

quartz, and chlorite. Analysis by J. E. Whitfield, record No. 519, 

Dried at 104°.

Q. Groundinass of red mottled quartzite.. Analysis by W. F. Hille 

brand, record No. 499.

E. Green mottlings from Q. Mostly quartz and sericite. Analysis 

by Hillebrand, record No. 498.

S. Another sample of the green mottlings, selected with especial 

care. Analysis by L. G. Eakins, record No. 1058.

T. Brilliantly red vitreous quartzite. Analysis by B. B. Eiggs, record 

No. 574. Dried at 105°.

SiO, ...........

TiO, ...........

Zr0.2 ...........

A1.-O;, ..........

Fe .0;3 ..........

FeO. ...........

MnO ...........

CaO ...........

SrO ............

BaO ....:......

MgO ...........

KiO.. ..........

Na^O.... .......

Li,0 ...........

H,0...... ......

PsOr, ...........

S03 ............

*

p.

68.36

1.57

13.76

2.65

2.75

.70

Undet.

Undet.

.68

4.48

3.56

.98

.33

.66

. 100. 48

Q.

76.57

.42

9.21

1.67

3.94

.05

.73

Trace?*

1.51

1.02

3.07

Trace.

1.89

100. 08

E.

77.70

.30

7.67

3.55

3.29

.04

.26

?

*1.83

1.04

I OR

Trace.

2.36*

100. 00

S.

. 83. 27

7.81

1.99

. 1.81

.20

1.59

1.11

.10

2.32

100. 29

T.

83.69

Trapft 9

7 PiO

1.81

.38

3Q

Undet.

Undet.

.35

2.61

2.46

.72

99.91

* Determined by difference.
CI.ARKE AND1 

H1LLEBUAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

5. MISCELLANEOUS ROCKS PROM MINNESOTA.

Ill

A. Granulitic hypersthene-gabbro. From SE. £ sec. 20, T. 65 N., E. 

4 W. Described by Bayley, Journal of Geology, vol. 3, p. 1. Contains 

liyperstliene, biotite, diallage, magnetite, and plagioclase. Poor in 

feldspar. Analysis by H. N. Stokes, record No. 1267.

B. Hypersthene from A. Analysis by E. A. Schneider, record No. 

1358.

C. Granulitic diallage-gabbro. SE. J of NW. £ of sec. 26, T. 64 N., 

B. 8 W. Described by Bayley, Jonrn. Geol., vol. 3, p. 1. Contains 

diallage, hyperstheue, magnetite, and plagioclase. Analysis by W. H. 

Melville, record No. 1403.

D. Olivine-ga-bbro. West side of Birch Lake, SE. £ of sec. 19, T. 

63 N., E. 4'W. Described by Bayley, Journ. Geol., vol. 1, p. 688. 

Contains a large proportion of diallage and olivine. Analysis by Stokes, 

No. 1267.

E. Olivine from D. Analysis by W. F. Hillebrand, record No. 1308.

SiO,.. ..........

TiO, ...........

Al 2Oi... ........

Cr^Os.. .........

Fe,03 ..........

FeO... ......... 

MnO ...........

CoO... .........

NiO .....".......

CaO.. ..........

MgO ...'........

KsO ............

Na2 0..i. .......

H2Oatl05°..... 

H2O above 105°. 

P2 06 .... .........

CO, ............

A.

46.96

.62

14.13

Trace.

.76

14. 95 

.93

.06

2.32

15.97

1.68

.35

.07 

1.26 

.03

100. 09

B.

48.44

Undet.

7.91

.33

20.88 

.92

1.44

19.35

.08 

None.

99. 35

c. 

49. 56

.48

17.81

2.76

9.48 

.06

9.70

5.93

2.87

| .50 

.67

Trace.

99.82

D.

45. 66

.92

16.44

Trace.

.66

13.90 

Trace.

.16

7.23

11. 57

.41

2.13

.07 

.83 

.05

100. 03

E.

35. 58

1.22

.92

Trace.

J 33. 91 

.35

1 .20

.90

26.86

.11

.20

100. 25
112 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Average gabbro. South quarter post, sec. 35, T. 61 N., R. 12 W. 

Described by Bayley in Jouru. Geol., vol. 1, p. 688. Contains plagioclase, olivine, pyroxene, and magnetite. Analysis by H. N. Stokes, 

record No. 1267.

G. Feldspar from preceding gabbro. Analysis by W. F. Hillebrand, 

record No. 1308.

H. Feldspar from gabbro, east side of North Fowl Lake. Analysis 

by Hillebraud, No. 1308.

I. Feldspar from gabbro. NW. J of SE. J of Sec. 23, T. 62 N., E. 10.

J. Feldspar from gabbro. Center of Sec. 25, T. 64 N., E. 8.

K. Feldspar from gabbro; Duluth and Iron Eange E. E.

Analyses I, J, K, by Hillebraud, record No. 1115.

H, I, J, K analyzed for W. S. Bayley, but analyses "hitherto unpub 

lished.

SiOa .........

Ti02 .........

AJ2 03 . ........

Fe^Oa ..-..-..

FeO. ......... 

NiO ..........

. MnO .........

CaO ..... ...

crn

MgO. ........ 

KsO. .........

NajO. ........

H3OatlOO°... 

H2 0 above 100° 

P205 .........

F.

46.45

1.19

21. 30

.81

9.57 

.04

9.83

7.90 

.34

2.14

.14 

1.02 

.02

100. 75

G.

51. 89

29.68

.32

.37

12.62

.38 

.50

3.87

^.07 

.39

100.09

H.

- 62.71

Trace.

. 19. 20

1.08

.93

.44

.81 

10.41

2.96

.23 

.92

99.69

I.

52.50

Trace.

30.15

.47

.15

12.82

.10 

.53

3.72

| .25

100. 69

J.

52.61

Trace.

29.80

.57

.23

Trace.

12.25

.20 

. ..53

3.80

} ;29

100. 28

K.

53.45

29.77

.33

.15

11.33

.11 

.68

4.33

| .23

100. 38
CT,ARKE AND"! 

HILI.KUKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 113

L. Garnetiferous gabbro, Granjte Falls. Collected for the Educational Series, and described by W. S. Bayley. Contains plagioclase, 

augite. garnet, magnetite, a little hornblende, some quartz grains, and 

apatite. Analysis by H. N. Stokes, record No. 1296. Sp. gr. 3.105.

M. Gabbro diorite, Minnesota Falls. Collected for the Educational 

Series, and described by Bayley. Essentially plagioclase and hornblende, with some kaolin, augite, and biotite. Analysis by Stokes, No. 

1296. Sp.gr. 2.935.

X. Pyroxene-schist, Odessa. Collected for the Educational Series, 

iind described by Bayley. Contains quartz, plagioclase, pyroxene, biotite, garnet, magnetite, and sulphide of iron. Analysis by Stokes, No. 

1296. Sp.gr. 2.770.

O. Mica-schist, bed of Cross Eiver, near Gunflint Lake. Description 

furnished by C. 'E. Van Hise. Contains biotite, quartz, feldspar (?), and 

pyrites. Analysis by T. M. Chatard, record No. 896.

P. Actiuolite-maguetite-schist. SE. £ of SB.J of sec. 34, T. 61 N., 

E. 12 W. Described by Bayley in Amer. Journ. Sci., 3d series, vol. 46, 

p. 178. Mainly actinolite and magnetite. Analysis by W. H. Melville, 

record No. 1403.

Q. Magnetite rock near the preceding, also described with P by 

Bayley. Analysis by Melville, No. 1403.

-

SiOa.. ..........

Ti02 ...........

AlsOa-- .........

Fe,03 ......---.

FeO.... ........

MhO .:.........

CaO...... ......

MgO ...........

K8o..:. ........

Na2O... ........

H,0atl05°.....

H,O above 105°.. 

P.Or,..-. ........

S03 ............

COs .... ........

FeS ............

L.

52. 31

18.35

5.90

11.06

7.33

1.00

M

2 on

J .35

99. 69

M.

48. 29

20.87

1.13

d Q3

14.32

7.54

.38

1.77

I

on

100. 12

N.

61. 04

16. 97

5.58

K 00

3.62

KK

1 Qfi

1 A.O } " 43

o 70

99.87

0.

. 64. 77

.60

14. 45

1.84

4.54

.11

2.33

2.34

K 03 '

1 "V7

.07

1.92

on

.60

.41

100. 58

P.

12.35

.12

.10

58.68

21.34

1.22

1 Q1

4.08

I f .U 19

.25

100.24 .

Q1.16

1.81

69.08

27.10

.33

KQ

OK

.06

100. 32

Bull. 14*
114 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. i«.

SOUTH DAKOTA.

A. Phonolite, Black Hills. Description famished by Whitman Gross. 

Contains sanidine, nephelite, eegirite, uoseau, and soiialite, with accessory sphene, apatite, and zircon, and possibly some rare zirconates or 

titanates. Also, sparingly, secondary zeolites and calcite. No magnetite, but minute ferritic flakes are disseminated through the rock. 

Analysis by W. F. Hillebrand, record No. 1618.

B. An earlier analysis of A, by H. N. Stokes, record No. 1314. This 

was made along the ordinary lines as regards "completeness," as requested by the collector, and without regard to minor accessory constituents. It serves well to illustrate the difference between the two 

modes of treatment, in comparison with the fuller analysis.

0. Tourmaliue-biotite-schist, north of Harney Peak, Black Hills. 

Described by Bayley for the Educational Series of Eocks. Contains 

quartz, biotite, tourmaline, a little garnet and rarely muscovite. iron 

ore, and apatite. Analysis by Stokes, record No. 1296.

SiO....... ..................

TiO.2 .......................

Zr02 .......................

AliO:,... ....................

Fe,0j ......................

FeO...... ..................

MnO ............ ...........

CaO...... ............ ......

SrO ........................

BaO... .....................

MgO .......................

KsO.. ......................

Na/)...... .................

LiaO .......................

H2 0 at 110° ................

H2 0 at>ovo 110° .............

P o

S03 ........................

s ..........................

Cl .........................

F

COS ...... ..................

A.

57.86

.22

.15

20.26

2.35

 .39

.21

.89

.04

.09

.04

5.19

9.47

.21

2.40

.03

.06

.03

.08

1 9\ (?)

None.

99. 97,

B.

58.60

20.98

' 2.22

.44

.20

1.13

.33

5.49

8.38

| 1.92

"

99.69

C.

66.77

17. 65

1.55

3.29

.56

2.13

4.49

.99

| 1.89

N

99.32
CLARKE AND"! 

HILLKBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 115

WYOMING.

Bocks studied by Whitman Cross, who has furnished the petrographic data. Analyses hitherto unpublished. Analysis I is by L. G. 

Eakins, record No. 1078. The others are by W. P. Hillebrand; one 

made in the Denver laboratory, and record Nos. 343,355,362, 368, 403, 

463, and 1668.

A. Wyoraingite, or leucite-trachyte, North Table Butte, Leucite Hills, 

contains sanidine, less leucite, phlogopite, ainphibole, diopside, apatite, 

and rutile (?). Sp. gr. 2.699,19°.

B. Wyomiugite, Fifteen-mile Spring, Leucite Hills. Composition 

like A. Sp. gr. 2.686, 23°.5.

C. Mica .(phlogopite) from B.

D. Groundinass of B. Sp. gr. 2.615, 16°.

Zirconia only looked for in A. The other analyses of Leucite Hills 

rocks are to this extent defective.

SiO3 .............

Ti02 .............

Zr02 .............

A12 03 ...- .........

 Cr203 ............

FeaOs ........... .

FeO.. ............

NiO. .............

MnO.. ...........

CaO .............

SrO...... ........

BaO ......... ....

MgO. ............

KaO. .-.-.-..... -.

NaaO. ............

Li2 0 .............

HoO at 110° ......

H20 above 110°...

pao5 .............

so3 ..............

COfl .. . ...........

Cl ..... .........

F ................

A.

54.17

2.67

.22

10.16

.05

3.34

.65

.06

4.19

.18

sq

6.62

11.91

1.21

.52

1.01 

1.59

.16

.49

.06

.36

100. 21 

.17

100. 04

B.

 54. 08

2.08

Undet.

9 4Q

.07

3. 19

1.03

.03

3.55

.20

.67

6.74

11.76

1.39

.79

2.71 

1.36

.29

.04

.49

99.98 

.21

99.77

C.

42.56

2.09

12.18

.73

2.73

Of)

.20

Trace?

1.00

22.40

10.70

.44

2.35 

.06

2.46

100. 80 

1.03

99.77

D.

58.13

1.48

Uudet.

11.72

3.01

1.01

2.24

.10

.29

K 70

12.58

1.36

no

1.16 

.32

.13

100. 31
116 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

E. Mica-leucitite, Fifteen-mile Spring, Leucite Hills. Contains leucite, phlogopite, diopside, very little sanidine, and apatite. Sp. gr. 

2.627,30°.

F. Mica-leucitite, Boar's Tusk, Leucite Hills. Composition like B. 

Sp. gr. 2.779,13.5°.

G. Rock from Pilot Butte, Leucite Hills, not yet named. Contains 

pale-green diopside, predominating; also phlogopite, perofskite, and 

magnetite, with a yellowish amorphous base having the composition of 

leucite plus uosite. Sp. gr. 2.857,22°.

H. Pyroxene (mixed) from F. and G. Sp. gr. 3.290, 20°. Analyzed 

in the Denver laboratory. P2O5 included with the TiO2 ..

I. Dacite 1? Garfield Peak. Phenocrysts of plagioclase and hornblende, with microscopic sphene and apatite in a groundmass containing plagioclase, orthoclase, quartz, and magnetite. Sp. gr. 2.570, 26°.2.

Si02 ...........

Ti02 ...........

A12 0:J - ..........

Cr2 O:i ..........

Di,O:i, etc*.....

Fe2O3 ..........

FeO. ...........

MnO ...........

CaO.-.. ........

SrO. ...'.. ......

BttO.. ..........

MgO ...........

KaO. .......... 

NagO. ..........

Li.,0 -- .........

HoO at 110° ....

H2O above 110°.

P

r\

C/-J

PI

r ..............

E.

53.70

1.92

11.16

.04

3.10

1.21

.04

3.46

1Q

.62

6.44

11.16

1.67

Trace.

.80

2.61 

1.75

.06

.03

.'44

100. 40 

.19

100. 21

F.

50.23

2.27

11.22

.10

.03

3.34

1.84

.05

5.99

.24

1.23

7.09

9.81

1.37

Trace.

.93

1.72 

1 89

.74

.03

.50

100. 62 

.22

100. 40

G.

42. 65

1.64

9.14

.07

Ml

5.13

1.07

.12

12.36

.33

.89

10.89

7.99

.90

2.04

2.18 

1.52

.58

.03

.47

100'. 11

.20

99.91

H.

50.86

t3.03'

1.19

1.82

.03

23.32

17.42

.42

.76

.31

99.16

I.

67.78

16.67

1.99

."51

Trace.

2.67

.71

3.43

4.91

I 1.44 

.19

100. 30

* Includes other rare earths, probably. t Includes P206.
CLAKKE AND" 

HILLEBRAND. IGNEOUS AND CRYSTALLINE ROCKS. 117

THE YELLOWSTONE NATIONAL PARK AND ITS IMMEDIATE

VICINITY.

1. ELECTRIC PEAK.

Eocks described by Iddings in 12th Ann., p. 577. Also in Bull. Phil. 

Soc. Washington, vol. 11, p. 206. For analyses O, P, see Mon. XXXII.

A. Pyroxene-inica-diorite. Contains augite, hypersthene, plagioclase, quartz, biotite, hornblende, magnetite, and apatite. Analysis by 

J. B. Whitfield, record No. 830.

B. Pyroxene-rnica-diorite. Same minerals as under A. Analysis by 

Whitfield, No. 921.

G. Pyroxene mica-diorite. Like A.-and B. Analysis by W. H. Melville, record No. 1231.

D. Pyroxene-porphyrite. Contains augite, hypersthene, biotite, magnetite, plagioclase, and quartz. Analysis by Whitfield, No. 830.

E. Quartz-pyroxene-mica-diorite. Contains biotite, hornblende, augite, hypersthene, magnetite, plagioclase, orthoclase, and quartz. Analysis by Melville, No. 1231.

SiOs.. ..........

TiO, ...........

A1203 .. .........

FesOa ..........

FeO... .........

MnO. ..........

NiO... .........

CaO.-.. ........

MgO ...........

KsO. ...........

NajO. ..........

Li2O .:..........

H20 at 100° .... 

H8O above 100° . 

P206 ...........

S03 ............

Cl ............

A.

56. 28

.84

14.23

4.69

4.05

.16

7.94

6.37

1.23

2.98

.01

j .93 

.40

Trace.

.17

100. 28

B.

58.05

1.05

18.00

2.49

4.56

1 None.

6.17

3.55

2.18

3.64

| .86 

.17

.07

 100. 79

c.

61.22

.61

16.14

3.01

2.58

Trace.

.09

5.46

4.21

1.87

4.48

.04 

.40 

.25

100.36

D.

57.38

Trace.

16. 86

2.49

5.17

Trace.

. 7.32

5.51

1.45

3.33

.39

} «

Trace.

.21

.17

100. 70

E.

64.07

.45

15.82

3.40

1.44

Trace.

.05

4.43

3.39

2.27

4.06

.10 

.42 

.18

100. 08
118 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Quartz-mica-diorite. Contains biotite, hornblende, augite, hypersthene, plagioclase, orthoclase, and quartz. Analysis by Whitfield, No. 

921.

G. Quartz-mica-diorite. Contains biotite, hornblende, plagioclase 

pyroxene, quartz, and orthoclase. Analysis by Whitfield, No. 921.

H, I, J. Q.uartz-inica-diorites. Contain hornblende, biotite, plagioclase, orthoclase, and quartz. Analyses by Whittield, Nos. 921 and 

830.

Si02 ...........

TiOo ...........

A1.03 . ..........

Fe.2 03 ..........

FeO. ...........

MnO. ..........

CaO ...........

MgO ...........

K2O... .........

Na.O. ..........

LL.O ...........

H8O... .........

PoO", ...........

' SO;, ............

Cl .............

F.

65. 11

.71

16.21

1.06

3.19

 3.97

2.57

2.51

4.00

.04

.94

.02

100. 33

G.

65. 60

17.61

.95

2.76

3.72

1 40

2.36

4.36

.03

.59

.16

100. 38

H.

64.85

.91

16.57

2.10

2.15

None.

4.01

2.14

3.10

3.71

None.

.35

.14

None.

 100.03

I.

66.05

.34

16. 96

2.59

1.38

None.

3.37

2.08

2.53

4.20

.69

Trace. '.03

Trace.

100. 22

J.

67. 54

. .80

17.02

2.97

.34

Traco.

3.36

o!3

2.28

4.62

.03

.55

Trace.

.26

.15

100. 05
CLARKE ANPT 

HILLKBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 119

K. Quartz-inica-diorite-porphyrite. Contains biotite, hornblende, 

plagioclase, orthoclase, and quartz. Analysis by WhMeld, No. 830.

L. Quartz-inica-diorite-porphyrite. Contains quartz, biotite, plagioclase, alkali-feldspar, and hornblende. Analysis by Whitfield, No. 830.

M. Hornblende-porphyrite; intrusive sheet. Contains hornblende, 

plagioclase, magnetite, and quartz. Analysis by Whitfield, No. 429.

N. Hornblende-mica-porphyrite; intrusive sheet. Contains hornblende, plagioclase, biotite, magnetite, and quartz. Analysis by Whitfield, No. 420. The Indian Creek laccolite.

O. Augite-andesite-porphyry; intrusive sheet, upper portion. Contains malacolite, plagioclase, probably orthoclase, magnetite, and little 

biotite, with secondary chlorite or serpentine and actinolite. Analysis 

by Whitfield, No. 830.

P. Same sheet as O, lower portion. Analysis by W. F. Hillebraiid, 

record No. 1571.

SiO2 - ...........

Ti03 . ..........

A13O3 - ..........

Fe303 ..........

FeO ...........

MnO. ..........

NiO...... ......

CaO.. ..........

SrO.... ........

BaO...... ......

MgO. ..........

Kn r\

NasO. .......... 

Li30. ..........

HoOiitllO0 ..... 

HS0 above 110°.

PsOr, ...........

so3 ............

O Cl. ....... ~

K.

65.97

.42

16.53

2.59

1.72

None.

3.37

2.11

2.67

3.41 

.09

1 1.23 

Trace.

.13

.09

100. 33 

.02

100.31

L.

69.24

.65

15.30

1.72

.69

Trace.

2.98

.95

2.52

4.46

| 1.30

.27

100. 08

M.

- 58. 49

1.71

16.70

3.85

2.37

.24

' 5.90

3.12

1.59

3.47 

.01

| 2.44

.63

100. 52

N.

61.50

17.42

4.66

1.09

5.33

1.26

1.29

3.99 

.03

| 2.44 

.60

.35

99.96

0.

52.10

.79

16.34

3.84

6.82

4.73

4, 33

4.20

4.02 

.13

1 1.74 

.68

.22

.24

100. 18 

ne

 100.13

P.

50.59

.80

11.53

1.83

7.64

.17

.06

8.79

.03

.10

11.27

2.33

2.27

.21 

1.76 

.48

99.86
120 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. us.

2. SEPULCHRE MOUNTAIN.

Rocks described by Iddiugs, 12th Ann., p. 633. Also in Bull. Phil. 

Soc. Washington, vol. 11, p. 210.

A. Pyroxene-andesite. Essentially composed of augite, hyperstheue, 

and plagioclase. Analysis by J. E. Whitfield, record No. 923.

B. Pyroxene-andesite. Composition like A. Analysis by Whitfield, 

No. 923.

0. Hornblende andesite. Essentially plagioclase and hornblende. 

Analysis by Whitfield, No. 922.

D. Hornblende-pyroxene-andesite. Contains augite, hypersthene, 

plagioclase, and hornblende. Analysis by T. M. Ohatard, record No. 

712.

E. Hornblende-pyroxene-andesite. Minerals as in D, with magnetite also. Analysis by Chatard, No. 712.

SiO2 ...........

Ti03 ...........

AlaOs..... ......

02 03 ...........

Fe2 03 ..........

FeO.... ........

MnO ...........

CaO... .........

BaO... .........

SrO ............

MgO ........... O

KaO. ...........

Na20. ..........

LisO ...........

HaOatlOS0 ..... 

H2O above 105°.

p 0.

SO3 ............

Cl.... ..........

A.

55.83

1.05 '

17.11

4.07

3.75

7.40

5.05

1.71

2.94

} 1.28 

.21

Trace.

100. 40

B.

57.17

1.03

17.25

2.48

4.31

6.61

4.83

2.03

3.44

Trace.

1 1. 20, 

.05

Trace.

Trace.

100. 40

C.

55.92

.94

17.70

3.16

4.48

5.90

4.34

2.24

4.08

.09

| 1.42 

.18

100. 45

D.

56.61

.79

13.62

.05

5.89

2.60

.35

6.61

.14

Trace.

5.48

2.71

3.13

1.20 

1.07 

.06

?

100. 31

E.

60.. 30

.76

16.31

Trace?

4.35

1.41

. 13

5.62

IK

Trace.

2.39

2.36

3.99

.64 

1.86 

.20

.10

100. 57
CLAKKE AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 121

F. Hornblende-mica-andesite. Contains plagioclase, hornblende, biotite and magnetite. Analysis by Whitfield, No. 924.

G. Hornblende-mica-andesite. Contains plagioclase, hornblende, and 

biotite. Analysis by Chatard, No. 712.

H. Dacite. Contains plagioclase, hornblende, biotite, and quartz. 

Analysis by Whitfield, No. 830.

I. Dacite. Minerals as in H. Analysis by L. GL Eakius, record 

No. 1135.

J. Andesite-breccia. Not in paper cited. See Mon. XXXII. Analysis 

by Chatard, No. 712. Keported by Iddings as hornblende-mica-andesite, 

containing hornblende, plagioclase, quartz, biotite, and a little magnetite.

SiO, ...........

TiO, ...........

A1203 ..........

Fe,0:i ..........

FeO.... ........

MnO ...........

CaO ...........

BaO ...........

SrO... .........

MgO. ..........

KaO... .........

NajO... ........

Li2O ...........

H2 0 at 105° .... 

TS.nO above 105°. 

P2 05 - ..........

S03 ............

Cl .............

F.

64.27

.32

17.84

3.36

1.29

None.

3.42

2.00

2.48

3.84

.03

} 1.32 

.16

Trace.

None.

100. 33

G.

(ft KO

.45

14.94

1.72

2:27

.20

2.33

.13

Trace?

2.97

2.76

5.46

.24 

1.13 

.09

.06

100. 25

H.

65.66

1.37

15.61

2.10

2.07

None.

3.64

2.46

2.03

3.65

.36

} 1.07 

Trace.

.13

.12

100. 27

I.

67 4Q

.13

16.18

1.30

1.22

.08

2.68

1.34

2.40

4.37

} 2.69 

.13

100.01

J.

W OK

.45

14.98

' 2. 33

Q<i

.09

3.98

.23

Trace?

1.42

2.86

4,39

.37 

.61

.07 ,

.11

100. 79
122 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

3. THE CKANDALL BASIN.

Eocks from a dissected volcano. Described by Idclings in MOD. 

XXXII. The analyses also appeared in Bull. Phil. Soc. Washington, 

vol. 12, p. 204.

A. Gabbro-porphyry, Hurricane Eidge. Contains augite, plagioclase, 

hypersthene, biotite, magnetite, and a little olivine. Analysis by L. G. 

Eakins, record No. 1089.

B. Basalt flow, north side of Timber Creek. Eich in olivine, augite, 

and magnetite. Analysis by Eakins, No. 1087.

C. Basalt dike, ridge south of Hurricane Eidge. Like B. Contains 

also labradorite and a little orthpclase. Analysis by Eakins, No. 1087.

D. Mica-gabbro-porphyry, Hurricane Eidge. Contains plagioclase, 

augite, hypersthene, biotite, and magnetite. Analysis by Eakins, No. 

1089.

E. Mica-gabbro, Hurricane Eidge. Like D, with some orthoclase and 

a little quartz and olivine. Analysis by Eakins, No. 1089.

F. Basalt-glass-breccia, ridge south of Indian Peak. A glass showing crystals of olivine, augite, plagioclase, and magnetite. Analysis by 

Eakins, No. 1087.

SiOa ...........

TiO2 ...........

A12O3 . ..........

FeaOs ..........

FeO. ...........

MnO. ..........

CaO. ...........

MgO. ..........

KsO.... ........

NasO. ..........

H2O.. .........

PS 08 ...........

A.

51.81

.77

15.24

3.66

4.86

.08

9.06

8.89

2.08

2.83

.67

.18

100. 13

B.

52.09

.39

17.84

4.27

4.56

.14

8.03

5.33

1.98

3.39

1.77

.27

100. 06

C.

52.11

KQ

16.58

3.66

4.99

.23

6.43

6.87

3.20

3.25

1.99

.63

100. 47

D.

53.56

.'68

16.07

3.21

o 9Q

.11

8.77

7.23

1.94

3.06

1Q

.18

100. 29

E.

KQ 71

.74

18.00

3.99

4.05

.24

6.88

5.19

Q 1ft

3.50

.55

.38

100. 33

F.

53. 89

4.Q

18.81

4.92

2.81

.17

5.42

3.29

2.98

3.65

9 QQ

.52

99.94
CLARKB AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 123

G. Orthoclase-gabbro-diorite, rich in mica. Hurricane Eidge. Contains orthoclase, plagioclase, quartz, biotite, augite, hypersthene, magnetite, and hornblende. Analysis by Eakins, No. 1089.

H. Another sample, like G. Same analyst and record number.

I. Dioritic fades of gabbro, Hurricane Eidge. Very feldspathic. 

Same analyst and number.

J. Monzonite, Hurricane Eidge. Contains orthoclase, biotite, augite, 

hypersthene, and magnetite. Analysis by W. H. Melville, record No. 

1233.

K. Augite-andesite-porphyry. Intrusive sheet, Hurricane Eidge. 

Analysis by Eakins, No. 1088. Contains plagioclase, augite, hypersthene, magnetite, biotite, quartz, and microscopic orthoclase.

Si03 . ...........

TiOo ...........

Al.O:,.... .......

Fo3 03 ..........

FeO.... ........

MnO ...........

NiO...... ......

CaO.. ..........

MgO. ..........

KoO. ...........

Nifc.0. ..........

H .0 :i,t 100° .... 

RjO above 100°. 

P»6r, ...........

Cl .............

G.

55.93

.81

18.32

2.39

4.91

.14

6.17

3.97

2.62

4.29

| .22 

.56

100. 33

H.

56.21

88

18.24

3.26

3.69

.17

5.91

 3.38

3.02

4.15

} .78 

.64

100. 33

I.

57.26

.76-

19.40

2.49

3.29

.16

5.68

2.57

2.95

4.21

| .86 

.51

100. 14

J.

^7 ^9

.62

17.29

3.89

3.03

.06

.10

5.81

3.56

3.04

3.89

.33 

.30

.50

99.74

K.

M fii

.77

18.43

3.63

2.84

.10

5.49

3.32

3.33

4, 03

} .*

.34

100. 43
124 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

L. Hornblende-mica-andesite-porphyry dike, ridge south of Hurricane Ridge. Contains plagioclase, hornblende, biotite, augite, hypersthene, and magnetite, with a little chlorite or serpentine. Analysis 

by Eakins, No. 1087.

M. Quartz-diorite-porphyry, Hurricane Ridge. Contains plagioclase, 

orthoclase, quartz, augite, hypersthene, magnetite, and a little, biotite. 

Analysis by Melville, No. 1234.

N. Quartz-mica-diorite, Hurricane Ridge. Contains audesine, orthoclase, quartz, biotite, hornblende, magnetite, and a little pyroxene. 

Analysis by Melville, No. 1234.

O. Quartz mica-diorite-porphyry, Hurricane Ridge. Contains andesine, orthoclase, quartz, and biotite. Analysis by Melville, No. 1234.

P. Aplite dike, Hurricane Ridge. Con tains quartz, orthoclase, oligoclase, biotite, magnetite, some chlorite, and a little hornblende. Analysis by Eakins, No. 1088.

SiOs .... ..........

TiO2 .............

Al,03 . ............

FesOa ............

FeO. .............

MnO .............

NiO.... ..........

CaO... ...........

MgO.. ...........

KaO.... ..........

Na.2O. ............

HsOatlOO0 ......

H2O above 100°... 

P2 0B .............

Cl ...............

L.

61. 16

.23

16. 17

2.89 .

2.18

Trace.

4.26

3.89

3.20

3.87.

} 2.09 

.13

100. 07

M.

63.42

.35

17. 16

3.09

1.50

,.04

.19

4.65

1.64

3.04

4. 51

.16

.28 

.26

100. 29

N.

63.97

.48

15. 78

2.35

1.87 .

.05

Trace.

3.71

2.84

4.01

4.36

.09

. .49

.40

100. 40

0.

64.40

-.40

15.77

2.47

1.15

.04 "

.17 

3.54

2.12

3.81

4.10

.31

1.93 

.16

100.37

P.

71.62

.08

14.99

1.27

1.01

.17

1.33

.74

4.81

3.62

f -

100. 05
CLAKKE AND" 

HILLEBRAND.. IGNEOUS AND CRYSTALLINE KOCKS. . 

4. ABSAROKITE-SHOSHONITE-BANAKITE SERIES.

125

Eocksfroin the Yellowstone Park and its immediate vicinity, described 

by Iddings in Journ. of Geology, vol. 3, pp. 038, 943, 947. The rock A, 

from Ishawooa Canyon, is also described by Hague in Amer. Journ. 

Sci., 3d series, vol. 38, p. 46.

A. Leucite-absarokite, Ishawooa Canyon,Wyoming. Bowlder. Contains olivine and augite in a grouudmass of orthoclase and leu cite. 

Accessory minerals, magnetite, apatite, and a few flakes of brown mica. 

Analysis by J. E. Whitfield, record No. 1057. Material dried at 104°.

B. Absarokite dike, head of Larnar Eiver. Contains olivine and 

augite in a groundmass of orthoclase and plagioclase, with accessory 

magnetite, biotite, and ilmenite.

C. Absarokite dike, south of Clark's Fork. Contains augite, quartz, 

biotite, magnetite, orthoclase, plagioclase, and sometimes analcite.'

D. Absarokite lava flow, head of Haven Creek, Contains olivine, 

augite, orthoclase, labradorite, magnetite, apatite, and a little serpentine.

B. Absarokite dike, divide east of Cache Creek. Contains orthoclase, plagioclase, augite, biotite, magnetite, serpentine, and occasional 

quartz.

Analyses B, 0, D, E by L. G. Eakins; record Nos. 1086, 1365.

SiOj... ...........

Ti02 .............

Ala03 .... .........

CrsOs... ..........

Fe3 03 ............

FeO... ...........

MnO .I...........

CaO. .............

BaO...... ........

MgO .............

K2 0. .............

NazO..... ........

H20... ...........

P206 .............

Cl. ...............

0 01............

A.

47.28

.88

11.56

3.52

5.71

.13

 9.20

13. 17

2.17

2.73

 2.96

.59

.18

100. 08 

.04

100. 04

B.

48.95

.49

12.98

3.63

4.68

,13

7.66

11.73

3.96

2.31

3.16

.67

100. 35

C.

48.36

1.18

12. 42

Trace.

5.25

2.48

.13

8.65

.29

9.36

3.97

1.46

5.54

.84

.

99.93

D.

51.76

.47

12.36

4 88

4.60

.11

7.14

9.57

3.83

1.99

3.05

.56

100. 32

E.

49.71

1.57

13.30

Trace.

4.41

3.37

.17

8.03

.46

7.96

4.81

1.49

4.07

.66

100. 01
126 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Shoshonite lava sheet, Lamar Eiver, south of Bison Peak. Contains plagioclase, orthoclase, augite, olivine, magnetite, and serpentine, 

with ainygdules of zeolite and calcite. Analysis by Eakius, No. 1086.

Gr. Shoshonite lava sheet, southeast fork of Beaverdam Creek. Contains plagioclase, orthoclase, augite, and serpentinized oliviue.

H. Leucite (?) Shoshonite lava sheet, mountain east of Pyramid 

Peak. Contains feldspars, olivme3 serpentine, augite, magnetite, brown 

mica, and impure leucite (?).

I. Olivine-free Shoshonite dike, northeast of Indian Peak. Contains 

augite, plagioclase, biotite, and magnetite.

J. Shoshonite lava sheet, Two Ocean Pass. Contains orthoclase, 

serpentinized olivine, magnetite, augite, chlorite, biotite, apatite, labradorite. Dried at 104°.

Analyses G, H, I by Eakins, Nos. 1371,1375, 1379. Analysis J by 

Whitfield, No. 906.

Si03 ... .........

TiOa ...........

Al,03 ...- .......

Fe.2 0:, ..........

FeO. ...........

MnO ...........

CaO.... ........

BaO ...........

MgO. ..........

K2 0.. ..........

Na2O. ..........

Li3 0 ...........

H2O.... ........

P2 05 ...........

SO;) .............

F.

50.06

.51

17.00

2.96

5.42

. .14

. 8.14

3.61

3.40

3.53

4.85

.66

100. 28

G.

53.49

.71

17.19

4.73

3.25

.14

6.34

.06

4.42

3.86

3.23

2.17

.43

100. 02

H.

52.49

.81

17.89

C 70

2.08

.09

7.01

Qfl

3.49

3.73

3.18

2.63

.55 0

100. 01

I.

54.86

.69

17.28

4.08

2.28

.19

5.42

.37

4.19

3.96

3.94

2.16

.48

99.90

J.

56. 05

.98

19. 70

3.74

'2.32

Trace.

4.34

2.51

4.44

3.29

.06

1.86

.66

.19

100. 14
CLARKE AND"! 

HILLEBRAND.J IGNEOUS AND .CRYSTALLINE ROCKS. 127

K. Banakite dike, head of Lamar Eiver. Contains augite, serpeutinized olivine, orthoclase, plagioclase, biotite, magnetite, ilinenite, apatite, and aualcite. Adjoins rock B. Analyses by Eakins, No. 1375.

L. Bauakite dike, Hoodoo Mountain. Like K, but with amygdaloidal zeolites. Analysis by Eakins, No. 1371.

M. Banakite dike, Ishawooa Canyon, Wyoming. Like K and L, but 

more feldspathic. Contains a little serpentine, probably from olivine; 

also possibly analcite or sodalite. Analysis by Eakins, No. 1086.

N. Banakite dike, near head of Stinkingwater Eiver. Like M, but 

with more serpentine. Analysis by W. H. Melville, record No. 1232.

QiO

Ti03 .............

AlsOa.. ...........

Fc,0n ............

FeO. .............

MnO..... ........

NiO. .............

CaO. .............

BaO.. ............

MgO .............

K2 0.. ............

Ha»0. ............

H2 0 at 100°. ......

H<,0 above 100°... 

Prv

K.

51.82

.71

16.75

4.56

3.36

.23

4.94

.26

4.03

5.02

3 Q1

T 3. 97 - 

.52

100. 08

L.

52.63

.81

16.87

4.52

3/11

.10

4.77

9Q

3.69

5.17

3.86

| 3. 65 

.63

100. 10

M.

51. 46

.83

18.32

4.61

2.71

.17

6.03

2.91

4.48

4.11

V :».89 

.&

100. 38

N.

^9 33

.71

18.70

4.95

1.83

.03

.14

4.71

2.69

5.45

4.51

.74 

2.71 

.81

100. 31
128 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOLL. 148.

O. Leucite-banakite lava sheet, southeast fork of Beaverdam Creek. 

Overlies rock Gr. Contains olivine, augite, leucite, feldspars, magnetite, apatite, and a little brown mica. Analysis by Eakins, No. 1378.

P. Earlier unpublished analysis of O, another sample, by J. E. 

Whitfield, record No. 907.

Q. Quartz-banakite dike, near head of Stinkingwater River. Contains plagioclase, orthoclase, quartz, biotite, magnetite, augite, and a 

little calcite. Analysis by Melville, No. 1231'.

R. Quartz-banakite dike, near Q. Contains plagioclase, orthoclase, 

quartz, biotite, magnetite, augite, chlorite, and serpentine. Analysis 

by Melville, No. 1232.

Si02 .............

Ti02 .............

ALOa..... ........

Fe2O3 ........ ....

FeO... ...........

MnO. ............

NiO.. ............

CaO.. ........ ....

BaO.. ............

MgO .............

KaO. .............

Na2O. ./........,.

Li3 0 ....;........

H2OatlOO° ......

H3 0 above 100°... 

P205 .............

S03 1 .. ............

Cl.. ..............

o.

52.93

.72

19.67

3.07

3.50

.15

4.69

.21

2 88

4.75

4.20

1 2.73 

.59

100. 09

P.

51. 56

'.65

21. 00

5.17

2.76

Trace.

4.83

2.52

4.13

4. 37 '

.13

1 2.27 

.69

.21

100.29

Q.

57.29

.72

18.45

4.38

1.20

Trace.

.12

3.57

2.08

5.43

4.43

.17

2.01 

.46

100. 31

ll.

60. 89

.49

17.14

3.32

.95

.09

10

-3.58

1.16

5.71

4.54

".39

1.22 

.27

99.94
CLARKE AND"! 

'HILLEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 129

The following analyses in this series are hitherto unpublished. 

Petrographic data communicated by J. P. Iddings.

S. Absarokite, Two Ocean Pass. Contains augite, olivine, orthoclase, magnetite, serpentine, little biotite, apatite, and an isotropic 

substance, probably glass. Analysis by J. E. Whitfield, record No. 906.

T. Shoshonite, Beaverdaui Creek. Analysis by Whitfield, No. 907. 

Probably the rock already represented by analysis G.

IT. Shoshonite, northeast spur of Sepulchre Mountain. Contains 

augite and serpentinized olivine, in a grouudinass of plagioclase, orthoclase, augite, magnetite, and apatite. Analysis by Whitfield, No. 908.

.V. Shoshonite, Baldy Mountain, Bear Gulch, Montana. Contains 

hypersthene, augite, olivino, plagioclase, orthoclase, and magnetite. 

Analysis by Whitfield, No. 909.

SiOs.. ............

Ti03 .............

AlsOa-. , ..........

Fe2 0:i ............

FeO.... ..........

MnO. ............

CaO.... ..........

MgO. ............

K2 0.... ..........

NajO. ............

Li3O .............

HsO,. ............

P2 05 .............

SO;, ..............

01.... ............

COa ..............

S.

51.68

1.08

14.07

4.71

4.57

Trace.

6.65

7.72

4.16

2.45

. 2.09

.72

13

100. 03

T.

52.86

1.04

17.51

5.18

3.31

6.51

4.18

3.41

3.22

.04.

1.76

.53

.22

1 .16

99.93

U.

51. 75

.86

17.48

6.42

1.46

8.20'

4.05

3.72

3.33

 2.26

.67

.17

100.37

V. '

si 07

Q7

18.38

3.06

4.22

5.43

2.38

3.37

3. 45

.03

.82

.42

03

2.92

100. 45

Bull. 148 9
130 ANALYSES OF EOCKS AND ANALYTICAL METHODS. [BULL. 148.

5. MISCELLANEOUS BOOKS. FIRST GROUP.

Collected and investigated by Arnold Hague and J. P. Iddings.

A. Black obsidian, Obsidian Cliff. Described by Iddings, 7th Ann. 

Contains 'microlites of augite and magnetite, with traces of quartz 

and feldspar. Analysis by J. E. Whitfield, record No. 224.

B. Red obsidian, Obsidian Cliff. Described by Iddings, 7th Ann. 

Like A, with ferric oxide replacing magnetite. Analysis by Whitfield, 

No. 223.

C. Obsidian, east of Willow Park. Black and opaque. Described 

by Iddings, Bull. Phil. Soc. Washington, vol. 12, p. 204. Analysis by 

Whitfield, No. 222.

D. Lithoidal rhyolite, Obsidian Cliff. Described by Iddings, Bull. 

Phil. Soc. Washington, vol. 12, p. 204. Contains quartz and sanidine, 

with a little magnetite and augite. Analysis by Whitfield, No. 425.

E. Rhyolite, Upper Geyser Basin. See Iddings, Bull. Phil. Soc. 

Washington, vol. 12, p. 204. Analysis by F. A. Gooch, record No. 114.

F. Ehyolite, Tower Creek. See Iddings, Bull. Phil. Soc. Washington, vol. 12, p. 204. Analysis by Gooch, No. 115.

Si03 .........

Ti02 .........

AU>3 .....---..

Fe,O3 ........

FeO.... ......

MnO. ........

CaO .........

MgO. ........

KSO... .......

Na2 0. ........

Li.2O .........

H2 0.... ......

PaOB .........

S03 ..........

FeSa.. .......

A.

74. 70

None.

13.72

1.01

.62

Trace.

.78

.14

4,02

3.90

.62

.40

99.91

B.

75.52

None.

14. 11

1.74

.08

None.

.78

.10

3.63

3.92

.39

.11

100. 38

C.

72.59

.52

13.47

1.58

1,32

None.

2.12

1.05

2.52

4.63

.18

.26

100. 24

D.

1 75.50

None.

13. 25

1.02

.91

None.

.90

.07

2.85

4.76

.06

.41

.32'

100. 05

E.

70.92

.16

13.24

3.54

.66

.14

1.42

.23

4.25

4.28

.57

M8

100. 59

F.

71.85

.43

13.17

2.17

1.34

.12

2.25

.63

3.89

4.06

.43

.14

100. 48
CLAKKE AND! 

HILLE13RAND.J IGNEOUS AND CRYSTALLINE EOCKS. 131

G-. Rhyolite, Great Paint Pots. Analysis by Gooch, No. 113, hitherto 

unpublished.

H. Ehyolite,N Elephant's Back. Porphyritic obsidian. Analysis by 

Whitfield, No. 423, hitherto unpublished. Reported by Iddings as containing quartz, sanidine, and a little augite and magnetite, in a glassy, 

microlitic groundmass.

I. Ehyolite, Mount Sheridan. Composition reported by Iddings as 

quartz and sanidine, with a little magnetite and augite. Analysis by 

Whitfield, No. 426, hitherto unpublished.

J. Ehyolite, Madison Plateau. Like I. Analysis by Whith'eld, No. 

427, not yet published.

K. Trachytic rhyolite. Elk Creek. Analysis by Whitfield, No. 428, 

hitherto unpublished. Reported by Iddings as containing sanidine, 

labradorite, and little biotite, in a groundmass of quartz and alkalifeldspar.

Si08 . ...........

Ti'Os ...........

AlaOa.. .........

Fe.:03 ...........

FeO. ...........

MnO. .........:

CaO. ...........

MgO. ..........

KaO.... ........

Na^O. ..........

Li.,0 ...........

HaO..... '...'--..

P2 0fl ...........

S03 ... .........

G.

75.71

1.25

11.11

1.56

.37

. .07

.88

.08

4.18

4.64

.35

100. 20

H.

75.34

None.

12.51

.42

1.55

.07

1.07

.32

4. 17

3.31

Trace.

.86

.42

100. 04

I.

75.89

.50

12.27

1.12

1.37

None.

.86

.29

3.42

3.23

.01

.82

None.

.28

100. 06

J.

75.19

None.

13.77

.61

1.37

.68

.09

3.33

3.83

.02

.65

.29

99.83

K.

64.65

Trace.

17.80

2.33

2.10

1.73

.81

2.83

4.18

.17

3.06

.43

100. 09
132 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

L. Trachytic rhyolite-tuff, Two Ocean Pass. Analysis by Whitfield, 

No. 906, liitherto unpublished. Eeported by Iddings as containing sanidine, labradorite, biotite, magnetite, and augite, in a somewhat altered, 

glassy groundmass. Also contains fragments of andesite.

M. Glassy trachyte, approaching rhyolite, Sunset Peak, Bear Gulch. 

Contains phenocrysts of sauidiue, plagioclase, and biotite. See Iddings, 

Bull. Phil. Soc. Washington, vol. 12, p. 205; also Mon. XXXII. 

Analysis by L. G. Eakius, record No. 1378.

N. Altered rhyolite, "Iron Pot," Lower Basin. Collected by W. H. 

Weed. Analysis by Whitfield, No. 546, hitherto unpublished.

O. Dacite-porphyry, Echo Peak. P. The same, Mount Holmes. 

Analyses by Whitfield, Nos. 421, 422, liitherto unpublished. Eeported 

by Iddings as containing plagioclase, probably oligoclase, quartz, little 

biotite, and magnetite.

SiO2 .. ..........

TiO2 ...........

AMV.. ........

Fe3 03 .....:....

. FeO. ...........

MnO. ..........

CaO.... ........

BaO ...........

MgO. .......... O

KjO. ...........

NajO. ..........

Li3O ...........

H2 0... .........

P205 - ..........

S03 .... ........

L.

61.15

.69

15.70

4.31

1.12

2.84

3.04 

2.22

1.54

7.05

.75

.18

100. 59

M.

69.45

.19

14.92

3.16

.23

.07

1.19

.03

.05

5.95

3.19

1.69

.06

100. 18

N.

89.20

None.

2.39

1.21

.79

1.11

5.09

None.

.44

100. 23

0.

747 51

None.

14. 83 .

1 OQ

.81

.47

2.72

4.38

.02

.92

Trace.

.24

99.99

P,

69.54

None.

17.95

2.50

.22

1.80

.50

1.21

4.30

1.96

None.

Q7

100. 35
CLARKE AND"! 

HILI-KBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 133

Q. Mica-dacite-porphyry, Bunsen Peak. Analysis by Whitfield, No. 

419, hitherto unpublished. Eeported by Iddings as containing oligoclase-andesine, quartz, biotite, little magnetite, apatite, and zircon.

E. Mica-dacite-porphyry, Birch Hills. Like Q in composition. Analysis by Whitfield, No. 718, hitherto unpublished.

S. Hornblende-mica-andesite-porphyry. Fan Creek. Analysis by 

Whitfield, No. 713, hitherto unpublished. Reported by Iddings as containing andesine-oligoclase, hornblende, and biotite, in a groundmass 

of feldspar (probably oligoclase and orthoclase), with a little magnetite, 

biotite, and hornblende.

T. Hornblende-mica-andesite-porphyry, Gray Peak. Analysis by 

Whitfield, No. 715, hitherto unpublished. Composition similar to that 

ofS.

SiO2 .............

Ti02 .............

A12O3 ...... .......

Fe.2 03 ............

FeO...... ........

MnO...... .......

CaO .............

MgO .............

K2O. .............

Na2 0. ............

Li2 0 .............

H3O...... ........

P CI

so3 ... ...........

Cl ...............

r*o

Q.

70.52

15.85

2.28

.36

.09

2.59

.09

3.43

3.93

Trace.

.35

.17

.29

99.95

R.

70.24

17.36

1.38

.79

2.74

.53

2.65

3.69 

None.

.71

Trace.

Trace.

100. 09

S.

65.63

17.00

2.55

1.19

3.48

2.03

1.64

4.42

.04

2.00

.07

Trace.

Trace.

97

100.32

T.

65.64

17.29

3.07

1.29

Trace.

1.98

1.78

2.44

5.77

.04

1.03

.23

Trace.

Trace.

.17

100. 73
134 ANALYSES OF EOCKS AND ANALYTICAL METHODS. [BULL. 148.

U. Hornblende-mica audesite, Crescent Hill. Analysis by Whitfield, 

No. 432, hitherto unpublished. Reported by Iddings as containing 

oligoclase-andesine, biotite, and subordinate decomposed hornblende, in 

a groundrnass of feldspar and quartz, with a little magnetite and biotite.

V, Hornblende-andesite, Tower Creek. Analysis by Gooch, No. 117, 

hitherto unpublished. Eeported by Iddings as containing plagioclase, 

hornblende, and a little augite.

W. Pyroxene-andesite, Agate Creek. Analysis by Whitfield, No. 

432, hitherto unpublished. Eeported by Iddings as containing augite, 

hypersthene, labradorite, and magnetite, in a glassy, microlitic groundmass.

X. Ehyolitic pearlite, collected for the Educational Series of Eocks. 

Analysis by H. N. Stokes, No. 1314, hitherto unpublished. From a bluff' 

opposite the Midway Geyser Basin. Eeported by Iddings as containing 

quartz, sanidine, plagioclase, and rarely augite and magnetite, with 

microscopic zircon and apatite, in a glassy groundmass.

SiOa .............

Ti02 .............

A12 03 . ............

Fe.2 03 ............

FeO.... ..........

MnO .............

t^.. ............

MgO .............

K«O"... ...........

Nas0............1.

Li2 0 .............

HsO... ...........

P8 06 .............

S03 ..............

Cl ...............

COj.... ..........

tr.

64.61

"NTriti A

18.62

2.78

.95

4.20

.85

2.36

4.37

.01

Q3

.30

.25

100. 23

V.

61.56

.87

14. 73-

4.47

1.23

.34

4.87

" 3.57

2.24

5.10

.1.42

.04-

100. 44

W.

61.45

2.80

15.07

4.46

1.18

5.37

3.02

1.22

4.00

.05

1 oq

.29

100. 14

X.

73.84

12.47

.32

.90

Trace.

1.08

.25

5.38

2.88

2.76

99,. 88
CLARKE ANQ~| 

HU.LEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 135

MISCELLANEOUS EOCKS. SECOND GKOUP.

Collected and investigated by Arnold Hague and J. P. Iddings.

A. Pyroxene-andesite, west of Duuraveii Peak. Analysis by F. A. 

Gooch, record 'No. 116, hitherto unpublished. Eeported by Iddings as 

containing labradorite, augite, hypersthene, and magnetite, in a microlit ic groundmass.

B. Basalt, southwest of Dunraven Peak. Analysis by Gooch, No. 

118, hitherto unpublished. Eeported by Iddings as containing augite, 

olivine, labradorite-bytownite, and magnetite, in a globulitic glassy 

groundmass.

C. Basalt, north spur of Prospect Peak. Analysis by J. E. Whitfield, record No. 431, hitherto unpublished. Eeported by Iddings as 

containing labradorite, augite, olivine, and magnetite. Little glass in 

groundmass.

D. Basalt, Yellowstone Canyon. Analysis by Whitfield, No. 430,

hitherto unpublished. Eeported by Iddings as containing labradoritebytowuite, augite, olivine, magnetite, and a little brown glass.

E. Basalt, Stinkingwater Canyon. See Iddiugs, Bull. Phil. Soc. 

Washington, vol. 12, p. 205. Analysis by W. H. Melville, record No. 

1232.

Si02 ...........

TiOj, ...........

A12 03 ..........

Fe,03 ..........

FeO. .....*......

MnO.-----......

NiO.. ..........

CaO ...........

MgO ...........

K2 0.. ..........

TSs^O... ........

LiaO. ..........

H30 at 100° .... 

H2 0 above 100°. 

P(X

SO.............

' s ..............

Cl .............

A.

56.47

.99

15. 33

2.54

4.53

.18

6.93

5.08

1.66

3.81

| 1.65 

.54

-

99.71

B.

51.70

1.24

15.18

2.09

8.54

Trace.

8.73

8.18

1.81

2.31

}. ...

.21

.09

100. 24

C.

47. 17

2.13

17.85

7.42

1.18

3.26

None.

10.12

6.54

.56

2.94

.02

| .65 

.20

.51

100. 55

D.

51.70

3.17

17.90

7.24 -

1.00

1.81

Trace.

6.94

2.77

1.62

4.17

.03

| 1.15 

.41

.32

100. 23

E.

52.37

.73

16.57

 6.34

2.35

.07

.12

8.54

5.27

2.45

2.99

1.18 

1.04 

.31

100. 33
136 ANALYSES OF ROCKS AND ANALYTICAL METHODS.- [BULL. 148.

1 F. Cainptonite ("?) dike, Stinking-water Canyon. See Iddiugs, Bull. 

Phil. Soc. Washington, vol. 12, p. 205. Analysis by Melville, No. 1232.

Gr. Kersantite, Bighorn Pass. Described by Iddings in Mou. XXXII. 

Contains hornblende, plagioclase, orthoclase, quartz, augite, biotite, 

magnetite, chlorite, calcite, and apatite. Augite and hornblende partly 

decomposed. Analysis by Whitfield, No. 714.

H. Basalt dike, north spur of Mount Washburn. Analysis by 

Whitfield, No. 717, hitherto unpublished. Reported by Iddings as 

approaching pyroxene-andesite in composition. Contains labradorite, 

augite, serpentiuized olivine, and magnetite, in a grouudmass of globulitic and inicrolitic bro^n glass.

SiOz . .......................

Ti03 .......................

AU>3 . ...... ...... ..........

Fe.jOs ......................

FeO... .....................

MnO .......................

NiO. .......................

PaO

BaO. ..;...--....----..---..

MgO .......................

K2 0... .....................

Na3 0. ......................

Li3 0 .......................

HsOatlOO0 ................

H20 above 100°. ............

P

f\

S03 ........................

CO-2 ........................

r.

50.99

.67

15.62

8.47

1.43

.07

6

KQ

5.23

3.05

3.39

1.39

2.48

.53

99.85

G.

#

48.73

1 <U

11.92

4,79

. 4.56

.36

9.24

5.93

2.47

2.62

T^TJJ PA

| 1.52

.32

.34

.11

5.80

100. 05

H.

W 75

20.75

4.50

3.53

7 18

3.76

1.37

4.16

Trnpft

} 1.55

.15

Trace.

None.

100. 70
CLARKE ANDl 

HILLEBEAND.J IGNEOUS AND CRYSTALLINE KOCKS. 137

MONTANA. 

1. THE MADISON AND GALLATIN VALLEYS.

Eocks collected by A. C. Peale arid Gr. P. Merrill. Described by 

Merrill in Proc. U. S. National Museum, vol. 17, p. 637. See also Bull. 

110, p. 47.

A. Basalt? From east side of Bozeman Creek, 2£ miles southeast 

of Bozeman. Contains oliviue and augite, chloritized and serpeutinized. The colorless groundniass contains apparently two feldspars and 

a pyroxene, with grains of iron oxide. Analysis by T. M. Chatard, 

record No. 517. Sp. gr. 2.86.

B. Pyroxene from A. Analysis by L. Gr. Eakins, record No. 1046.

C. Portion of A soluble in hydrochloric acid. Contains olivine, iron 

oxides, and decomposition products. Analysis by Eakius, record No. 

817.

SiOa...... ..................

Ti02 .......................

Alj03 .. ....... ......--......'

Cr2 03 .- .....................

Fe,O3 ......................

PeO. .......................

MnO .......................

CaO.. ......................

MgO. .......................

K20... .....................

NajO. ......................

H2 0atl20° ................

H2O above 120°... ..........

PS06 .......................

A.

46.90

.41

10.17

.33

1.22

5.17

.10

6.20

20.98

2.04

1.16

1.04

4.38

.44

100. 54

B.

52. 50

2.26

1.07

2.05

2.47

21.70

17.11

.07

.35

| .64

100. 32

C.

20.88

3.89

2 01

4.28

.1.01

16.44

48.71
138 ANALYSES OF ROCKS AND ANALYTICAL METHODS. BULL. U8.

D. Highly altered porphyrite 1? Hills 1 mile north of East Gallatin 

River, near Camp 6. Eock contains hornblende paramorphs after 

augite in a devitrified base, with amygdules of calcite, chloritic and 

ferruginous matter derived from porphyritic augite and olivine. The 

base is also filled with needles, which may be mica. Analysis by 

Bakins, record No. 820.

E. Lamprophyre. From Oottonwood Creek. Contains porphyritic 

augite and olivine in an indeterminate grouudmass carrying augite, 

iron oxides, and mica. Analysis by Chatard, record No. 516.

F. Augite-porphyrite, Cottonwood Creek. Contains feldspars, augite, 

and brown mica, with iron oxides, apatite, glass, and secondary calcite 

and chlorite. Carries porphyritic plagioclase and augite. No unaltered 

olivine-visible. Sp. gr. 2.785. Analysis by Eakins, record No. 819.

SiO2 .......................

Ti02 .......................

A12 03 . .............. ........

Cr203 ......................

Fe203 .......................

FeO... .....................

MnO.... ...................

CaO .......................

BaO .......................

MgO.... ...................

KaO. .......................

NajO. ......................

H2 0atl20° ................

H2 0 above 120°... .........:

P2 05 ...:...................

S03 ........................

C0.2 ...... ..................

D.

49.47

.21

12.15

Trace.

1 Q3

4.07

.10

9.30

.03

10.86

2.42

2.08

1 4.14

.37

3.31

100. 44

E.

51.65

.55

13.89

.08

2.70

4.80

.15

4.07

.19

11.56

4:15

2.99

1.30

1.89

.21

.19

100. 37

F.

52.33

.14

15.09

4, 31

4.03

.09

7.06

.07

6.73

3.76 -

3.14

1 2. 68

1.02

100. 45
CLARKE AND") 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 139

G. Basalt 1? From Bear Creek. Resembles A, but with a more crystalline groundmass. Contains plagioclase, possibly sanidine, augite, 

olivine, and iron oxides. Analysis by Cbatard, record No. 1154.

H. Lamprophyre. Between South Boulder and Antelope creeks. 

Contains porphyritic augite and olivine in a felclspathic groundmass, 

with apatite, augite,.grains of iron oxide, and shreds of brown mica. 

Sp. gr. 2.96. Analysis by Eakins, record No. 1266.

I. Lamprophyre. Hills east of South Boulder Creek. Nodules from 

a decomposed mass. Shows sanidine, plagioclase, brown mica, and 

altered oliviue.

Si08 ...... ........

Ti02 .............

AlsOs ..........

Cr2 03 ............

Fe.2 03 ............

. FeO...... ........

NiO. .............

MnO. ............

CaO. .............

BaO...... ........

MgO. ............

K2 0.... ..........

NajO. ............

H2OatllO°.......

H2 0 above 110°... 

P206 .............

G.

49.13

' .42

9.05

.39

3.57

5.05

.15

5.68

.05

17.21

2^24

2.01

.84

3.50 

.38

99.67

H.

50. 82

.59

11.44

.03

.25

8.94

Trace.

.19

8.14

.06

14.01

3.45

1.79

I «

.20

100. 49

I.

50. 03

.61

14.08

Trace.

2.92

6.11

Trace.

.08

7.46

.04

10. 73

2.64

1.46

| 3.70 

.42

100. 28
140 ANALYSES OF ROCKS AND ANALYTICAL METHODS. BULL. 148.

J. Hornblende picrite, North Meadow Creek. Contains hornblende, 

abundant fresh olivine, grains of pleonaste and iron oxides, and occasionally hypersthene. Sp. gr. 3.35.

« K. Pyroxenite. Divide between Meadow and Granite creeks. Contains hornblende and hypersthene, with grains of iron oxide.

L. Hypersthene-andesite, northwest of Eed Bluff. Contains plagioclase and pyroxene, with an amorphous glassy base, and sometimes 

olivine altered to chloritic matter.

M. Peridotite, var. wehrlite. Hills 3 miles northwest of Eed Bluff. 

Contains olivine, diallage, brown mica, rarely plagioclase, and secondary 

iron oxides. Sp. gr. 3.37. Analyses J, K, L, M by Eakins, record No. 

1266.

SiOs .. ............

Ti0.a .............

A12 03 ...... .......

Cr303 ............

Fe2O3 ............

FeO.... ..........

MnO .............

NiO.... ..........

CaO. ..............

BaO. .............

MgO .............

K2O...... ........

Na3 0,. ...........

H2O.... ..........

PA .............

s ................

Less O ...........

J.

46.13

.73

4. fiQ

.04

.73

16. 87

.09

4.41

25.17

.08

1.38

.07

.24

100. 63 

.12

100. 51

K.

51.83

.29

7.98

.31

1.48

8.28

.11

5.26

24.10

.06

.35

.29

09

100. 43

L.

59.48

.93

16.37

.03

3.21

3.17

19

4 88

.13

3.29

2.81

3.30

2.01

.41

100. 21

M.

48.95

.81

5.69

.05

/ 1.20

12.11

.08

- .16

5.33

23.49

.79

1.58

.18

.12

100. 54
CLARKE ANDl 

U1LLEBRAND.J IGNEOUS. AND CRYSTALLINE ROCKS. 141

The following rocks, at first supposed to be Pliocene sandstones, were 

also described by Merrill. Amer. Journ. ScL, 3d series, vol. 32, p. 119. 

All consist of pumiceous volcanic glass. 0, from Idaho, is included 

here for convenience. Analyses by J. E. Whitfield, record No. 382.

A. Little Sage Creek.

B. Devils Pathway.

C. Marsh Creek Valley, Idaho.

Iron and alumina weighed together. The iron is mostly in the ferrous form.

SiO, .......................

AljOu, Ve2O^.. ..............

CaO .......................

MgO. ......................

K2O.... ........ .............

KaiO. ......................

H2 0atl05° ................

A.

65.56

18.24

2.58

.72

3.94

2.08

1.12

6.50

100. 74

B.

65.76

17.18

2.30

Trace.

3.14

2.22

3.46

5.60,

99.66

C.

68.92

16.22

1.62

r Pvn PA

4.00

1.56

1.60

6.00

99.92

The following examples of volcanic dust or sand, from the Gallatin 

Valley, were collected by A. 0. Peale. That marked E belongs to the 

Educational Series of Eocks. Analyses A, B, 0, D by F. W. Clarke, 

record No. 379. Analysis E by H. N. Stokes, record No. 1314.

A. Dry Creek Yalley, above the mouth of Pass Creek.

B, C. Near Bozenian.

B. Near Fort Ellis.

E. Gallatin Valley.

SiOs.. ..........

AliOs.-- -..-.."..

Fej03 ..........

FeO...... ......

MuO. ..........

CaO....'........

MgO ...........

K2 0. ...........

NajO. ..........

CaC03 . .........

A.

46.09

| 14.35

1.61

1.29

J 1.47

6.45

28.72

99.98

B.

61.82

| 19.86

1.78

.51

1.31

2.38

11.47

99.13

C.

71.01

| 15.17

1.19

".34

2.97

2.77

fi 34

99.79

D.

60.98

| 21.69

1.83

1.33

1.23

.80

11.96

99.82

E.

68.68

12.69

1.14

1.17

Trace.

1.11

1.14

5.58

1.23

7 QQ

100. 73
142 ANALYSES OF EOCKS AND ANALYTICAL METHODS. BULL. 148.

2. THE CRAZY MOUNTAINS.

The greater number of the rocks in this group were received from J. 

E. Wolff, who has supplied the petrographic data. The few exceptions 

are properly indicated. The three tinguaites and the elaeolite syenite 

were described by Wolff and Tarr in Bull. Mus. Oompar. Zoology, vol. 

16, No. 12,1893, in a paper upon u Acrnite-Trachyte from the Crazy 

Mountains." The renaming of these rocks is due to Wolff. The analyses, except when otherwise stated, are by W. F. Hillebrand, record 

No. 1438.

A. Granitite, Big Timber Creek. Small dikes in main diorite stock. 

Contains quartz, orthoclase, plagioclase (oligoclase), and biotite.

B. Hornblende-granitite, main stock, Big Timber Creek. Contains 

biotite, hornblende, quartz, orthoclase, and plagioclase (oligoclase).

C. Granite-porphyry, intrusive sheet, north part of the mountains. 

Contains orthoclase, albite, quartz, biotite, and green hornblende, in a 

groundrnass of quartz and untwiuned feldspar.

I). Porphyrite, intrusive sheet, Sweet Grass Creek. Contains hornblende and andesine in a groundmass of plagioclase, orthoclase, and 

quartz, with accessory magnetite.

E. Porphyrite, dike in contact zone, Sweet Grass Creek. Contains 

brown hornblende, biotite, and labradorite, in a groundmass of plagioclase, biotite, and hornblende, with a little quartz and orthoclase.

F. Porphyrite, intrusive sheet, middle peak of Three Peaks. Andesine, hornblende, augite, and biotite in a groundmass of plagioelase, 

orthoclase, and quartz.

Si02 ...........

Ti08 . ..........

AlaOa ......---.

Fe2 03 . .........

FeO ...........

MnO. ..........

CaO ...........

SrO. ...........

BaO. ..........

MgO. ..........

K20.... ........

NasO.... .......

LUO ...........

HaOatllO0 .... 

H2 0 above 110°. 

P206 ...........

A.

74.37

.29

13.12

.73

.87

Trace.

1.26

.10

.35

6.09

2.57

.05 

.25 

.06

100. 11

B.

fi4 4-7

.75

15.45

2.25

2.25

.06

 3.63

.04

.23

2.68

Q 1Q

° 4.54

Trace?

.05 

.63

.22

100. 44

C.

69.93

.33

14.*95

1,78

.55

1.46

.06

.29

.60

Q qq

5.30

.12 

.32 

.33

100. 01

D.

66.28

.50

16.21

.80

2.06

3.53

.05

.34

1 ^7

3.20

4.36

Trace?

.12 

.78 

.20

100. 00

E.

64.49

.51

17.25

.86

2.42

3.79

.08

.30

1.24

4'. 15

4.19

.06 

.54 

.23

100. 11

F.

61.08

.73

16.62

2.87

2.56

Trace.

3.66

.08

.32

1.65

3.90

4.75

.44 

.97 

.63

100. 26
CLARKE AND"! 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE EOCKS. 143

G. Porphyrite, intrusive sheet, north of Shield's Eiver Basin. Contains plagioclase, hornblende, and biotite, in a gronndmass of plagioclase, a little orthoclase, augite, hornblende, and magnetite.

H. Porphyrite, intrusive sheet, northern part of the mountains. Contains brown hornblende, green augite, and plagioclase, in a groundmass 

of plagioclase, augite, and magnetite, with accessory apatite.

I. Syenite,ridge north of Shield's Eiver Basin. Contains hornblende, 

green augite, and anorthoclase, with accessory sphene, apatite, and 

magnetite.

J. Diabase-porphyrite (?), dike south of Shield's Eiver Basin. Contains labradorite and decomposed augite in a groundmass of plagioclase, epidote, and chlorite.

K. Diorite-porphyrite, Big Timber Creek. Contains labradorite, 

augite, hornblende, biotite, orthoclase, quart/, magnetite, and apatite.

L. Quartz diorite, main stock on Sweet Grass Creek. Contains hornblende, biotite, augite, labradorite, orthoclase, and quartz, with accessory apatite, magnetite, olivine, and hypersthene.

1

SiOa-. ..........

'TiOa ... ........

A1.2 03 -... .......

Fe,0a .. .........

FeO... .........

MnO. ..........

CaO.... ........

SrO...... ......

BaO ............

\MgO ...........

K3O. ...........

Na2 0. ..........

Li,O ...........

H2OatllO°..... 

H20 above 110°. 

P2 05 .. ..........

Cl. ....'.........

CO8 ... .........

G.

56.75

.86

16.40

4.78

3.10

.17

5.34

.10

.33

3.22

3.36

4.19

Trace?

.40 

.82 

.52

100. 34

H.

54.69

.91

16.53

4.54

2.83

.07 ,

5.34 ,

.06

.37

2.99

3.93

5.19

Trace ?

.32 

1.05 

.73

.83

100. 38

I.

58.28

.64

17.89

3.20

1.73

.06

3.69

.05

.36

1.51

5.34

5.89

Trace.

.17 

.98 

9R

100. 05

J.

58.28

.96

19.37

1.35

2.98

.07

4.78

.09

.25

1.30

3.75

4.40

Trace?

.44 

1.78 

.35

.33

100. 48

K.

.54.56

1.34

17.58

4.30

 4.98

.06

6.00

.08

.27

2.86

2.70

4.43

Trace.

« .02 

.38 

.60

100. 16

L.

53.48

1.07

19. 35

2.37

4.90

.06

7.55

.11

.19

3.67

1.41

4.07

Trace?

.16 

.80 

.62

.08

99.89
144 ANALYSES OP BOOKS AND ANALYTICAL METHODS. BULL. 148.

M. Diorite, head of Eock Creek. Contains biotite, labradorite, and 

augite, in a groundmass of plagioclase, orthoclase, and quartz, with 

accessory magnetite, apatite, and hornblende.

N. Diorite, main stock, Big Timber Creek. Contains biotite, augite, 

labradorite, quartz, orthoclase, apatite, and magnetite.

0. Olivine-gabbro, Big Timber Creek. Contains labradorite (*?), 

brown hornblende, augite, olivine, and magnetite.

P. Eock from Musselshell Eiver, north of Crazy Mountains. Eeceived from J. S. Diller, but undescribed. Eegarded by W. H. Weed 

as monchiquite. Analysis by L. G. Eakins, record No. 1021.

Q. Hornstone, metamorphosed shale, contact zone, Sweet Grass 

Creek. An aggregate of augite, quartz, triclinic feldspar, and biotite.

SiOj.. ..........

TiO2 ...........

AlaOj.. ........ .

FfcOs ..........

FeO.. ..........

(CoNi) 0. ......

MnO.... .......

CaO. ...........

SrO.... ........

BaO .......:...

MgO. ..........

KaO.. ..........

Na2O. ..........

LijO.... .......

H2O at 110° .... 

H2 0 above 110°.

pa oB .......:...

rr>

Cl ......."......

F ..............

M.

57.97

.60

15. 65

.73

2.80

10.93

.02

OQ

4.96

3.16

3.03

T^TtO prt

.22 

.38 

.15

100. 69

'N.

50.73

1.59

19.99

3.20

4.66

.05

8.55

.11

.27

3.48

1.89

4.03

T^rn^A

.11

.66

.81

100. 13

O.

40.42

2.51

9.98

9.83

10.67

.02

.25

10.78

.02

.05

11.56

.60

1.26

Trace.

.45 

1.17 

.63

100. 20

P.

44.66

1.02

12.12

 5.81

3.20

.21

8.14

8.77

2.75

4.47

| 4.33 

2.02

2.19

99. 69

Q.

57.31

.52

14.24

1.00

3.24

.08

11.31

Trace?

.19

4.60

4.55

2.64

Trace?

.25 

.24 

.18

.17

100. 52
CLARKE AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 145

E. Elfleolite-syenite, Peaked Butte, northeast side of the mountains. 

Described by Wolff and Tarr, I c. Contains anorthoclase, augite, 

occasionally sodalite, aegirine, apatite, magnetite, and some interstitial 

nephelite. Analysis by W. H. Melville, record No. 1291.

Ea. Anorthoclase from E. Analysis by W. F. Hillebrand, record No. 

1297.

S. Tinguaite, var. solvsbergite; intrusive sheet north of Shields 

Eiver.

T. Tinguaite, var. solvsbergite, dike north part of mountains.

U. Tinguaite, var. solvsbergite, dike at head of Sixteen-mile Creek.

S, T, and U are the rocks described by Wolff and Tarr in their paper 

upon "Acmite-Trachyte." Mineral composition the same as under E. 

Analyses by W. H. Melville, record No. 1291.

SiO»... .........

Ti09 . ..........

AloO:,.- .........

Fea0.i .......... 

FeO.. ..........

MnO.. .........

CaO.... ........

SrO. ...........

BaO ...........

MgO ...........

K2 0. ...........

Na»0 ....... ....

H30 at 105° .... 

H2 0 above 105°.

paofi ...........

E.

59.66

16.97

3.18 

1.15

.19

2.32 0

.80

4.17

8.38

.07 

2.53

.14

99.56

Ea.

62.31

22.63

.63

.57

.77

4.79

7.68

.16 

.72

100. 26

S.

58.70

rP"rn PA

19.26

3.37

.58

.10

1.41

.76

4.53

8.55

.07 

2.57 

.10

100. 00

T.

62.17

TVo f»p

18.58

2.15 

1.05

T^TJI PA

1.57

' .73

3.88

7.56

.07 

1.63 

.11

99.50

U.

64. 33

17.52

3.06 

.94

.35

.56

.34

4.28

7.30

.04 

.95

99.67

V. Theralite, Gordon's Butte. Contains green augite, aegirine, biotite, olivine, nephelite, sodalite, and a feldspar partly sanidine, containing K, Na, Ba, Sr, and Ca; also accessory apatite, magnetite, and 

sphene.

W. Theralite, Gordon's Butte; another sample. Analysis by E. A. 

Schneider, record No. 1281.

X. Theralite, north of Alabaugh Creek. Described by Wolff for the 

Educational Series. Contains augite, eegirine, biotite, olivine, magnetite, apatite, nephelite partly zeolitized, a mineral of the sodalite 

group, sanidine, and analcite. Analysis by Schneider, No. 1281.

Y. Altered theralite, head of Shields Eiver, west of Loco Mountain. 

Bull. 148 10
146 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Eeceived from W. H. Weed. Analysis by H. N. Stokes, record No. 

1547.

Z. Hornblende-picrite, Conical Peak. Data supplied by J. P. Iddings. 

Contains hornblende, plagioclase. liypersthene, augite, olivine, very little 

primary quartz, and probably some magnetite and apatite. Analysis 

by L. G. Eakins, record No. 1379.

SiOa ..... ......

Ti02 ...........

AljOs ..........

CrsO3 ..........

Fe3 03 ..........

FeO... .........

MnO. ..........

CaO. ...........

SrO. ...........

BaO ...........

MgO ...........

KaO. ...........

Na,0. ..........

Li.,0 ...........

HoO at 110° .... 

H2 0 above 110°.

PiOfi..........:

COs.. ..........

S03 ...- ........

Cl .............

-

V.

44.65

.95

13.87

6.06

2.94

.17

9.57

.37

.76

5. 15

4.49

5.67

.96 

2.10 

1.50

.11

.61

99.92

W.

44.31

Undet.

17.20

4.64

3.73

.10

10.40

6.57

3.64

4.45

.77 

3.30

99.11

X.

47.67

Undet.

18.22

3.65

3.85

.28

8.03

6.35

3.82

4.93

" .38 

2.97

100. 15

 . Y.

48.90

.95

14.70

4.14

3.68

.03

8.26

.13

.31

3.95

.56

5.22

Trace.

.52 

2.44 

.79

5.42

.04

100. 04

Z.

45.71

1.83

10.80

.10

4.43

9.35

.17

10.48

Trace.

13.75

.85

1.58

1 .97 

.11

100. 13

3. THE LITTLE BELT MOUNTAINS.

Eocks collected by W. H. Weed and L. V. Pirsson, who furnish the 

petrographic data. To be described in a forthcoming Bulletin of the 

Survey on the Neihart and Barker mining districts. Analyses by 

W. F. Hillebrand, record No. 1476, and H. N. Stokes, record No.. 1547.

A. Quartz-porphyry, Yogo Peak, sheet at head of Belt and Euiming 

Wolf creeks. Phenocrysts of orthoclase and quartz in a groundmass 

of quartz and alkali-feldspar, with a little white mica and some kaolin. 

Chlorite, limonite, and calcite are also present, pseudomorphous after 

biotite and perhaps hornblende. Total amount of secondary minerals 

very small. Analysis by Hillebrand.

B. Granite-porphyry, Wolf Butte. Phenocrysts of quartz, orthoclase, 

plagioclase, and biotite in a groundmass of quartz and alkali-feldspar. 

A little apatite and iron ore, with secondary calcite, limouite, chlorite, 

and white mica. Analysis by Stokes.
CLARKE AND"! 

HILLEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 147

C. Granite-porphyry, top of Barker Mountain. Phenocrysts of 

orthoclase, oligoclase, biotite, green hornblende, sphene, and iron ore, 

in a groundmass of quartz and alkali-feldspar. Also a little apatite 

and.some secondary chlorite and limonite. Analysis by Stokes.

D. Syenite, Wright and Edwards's mine, Hughsville, near Barker. 

Very fresh rock. Contains magnetite, ilmenite, hornblende, anorthoclase, albite, subordinate quartz, a little chlorite, calcite, and limonite, 

and white mica in traces. Analysis by Stokes.

E. Syenite, Yogo Peak. Described in Amer. Jourii. Sci., 3d series, 

vol. 50, p. 471. Contains apatite, sphene, iron ore, pyroxene, hornblende, biotite, orthoclase, oligoclase, and quartz, with traces of chlorite and limonite and a little kaolin. Analysis by Hillebrand. *

F. Syenite-porphyry, dike at head of Sheep Creek. Phenocrysts of 

orthoclase, some plagioclase, and green hornblende, in a groundmass 

of alkali-feldspar, with some quartz. Also contains a little apatite 

and iron ore, with some secondary calcite and kaolin. Analysis by 

Hillebrand.

SiOa... .........

TiOB ...........

AlaOs.-. .....

Cr803 ... ........

Fe2 03 ..........

FeO.... ........

MnO.... ........

CaO.... ........

SrO. ...........

BaO.. ..........

MgO. ...........

kgO... .........

NasO.... .......

Li,0 ...........

HjOatllO0 ..... 

H2O above 110°. 

PBOB ...........

COB ............

S03 ............

ci ........:....

A.

73.12

.08

14.27

.51

.26

.06

1.10

Trace.

.24

4.90

3.43

.68 

/73 

.03

.77

100. 18

B.

69.68

.28

14.97

.79

.34

2.10

.06

.14

.66

4.40

3.38

1.09 

.92 

.17

.88

99.86

C.

68.60

.32

16.13

2.22

.44

1.36

.09

.27

.72

4, 89

4.37

.20 

.58 

.18

100. 37

D.

64.64

.51

16.27'

2.42

1.58

2.65

.08

.18

1.27

4.98

4.39

.09 

.27 

.37

07

Trace.

.05

100. 12

E.

61. 65

.56

15.07

2.03

2.25

no

4, 61

.10

.27

3.67

4. 50

4. 35

.26 

.41 

.33

100. 15

J.

66.29

.27

15.09

1.37

1.17

.06

2.38

.07

.30

2.39

4. 91

3.96

'.39 

.60 

.15

.45

99.85

G. Syenite-porphyry, intrusive sheet, between Yogo Peak and Big 

Baldy Mountain. Abundant phenocrysts of hornblende and orthoclase, 

with less biotite and plagioclase, in a groundmass of alkali-feldspar 

with accessory quartz. Also contains iron ore and apatite, with secondary calcite, chlorite, sericite, and kaolin. Analysis by Hillebrand.
148 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

H., Granite-syenite-porphyry, north end of Thunder Mountain. Phenocrysts of orthoclase, oligoclase, hornblende, and biotite, in a groundmass of alkali-feldspar and very abundant quartz. Also contains a 

little sphene, iron ore, and apatite, very little secondary chlorite and 

limonite, and a trace of kaolin. Analysis by Stokes.

I. Quartz-syenite-porphyry, top of Big Baldy Mountain. Phenocrysts 

of orthoclase, plagioclase, biotite, iron ore, brown hornblende, and 

sphene, in a groundinass of quartz, and alkali-feldspar. Also contains 

a little apatite, with traces of chlorite, limonite, and kaolin. Analysis 

by Hillebrand.

J. Syenite-diorite-porphyry, talus slope on west slope of Bear Park. 

Phenocrysts of biotite, hornblende, plagioclase, and orthoclase, in a 

groundmass of quartz and alkali-feldspar. Also contains a little magnetite, chlorite, white mica, and apatite. Analysis by Stokes.

K, Diorite-porphyry, Steamboat Mountain. Phenocrysts of orthoclase, plagioclase, hornblende, and biotite, with a little iron ore and 

apatite, in a groundmass of orthoclase, plagioclase, and quartz. Analysis by Stokes.

L. Diorite, Carpenter Creek, near Neihart. Contains green hornblende, biotite, and plagioclase, with some apatite, iron ore, calcite, 

kaolin, and muscovite, and a very little quartz and orthoclase. Analysis 

by Hillebrand. .

SiO-i ...........

TiO, ...........

AlaO3 .. .........

Fe2 03 ..........

FeO...... ......

MnO ...........

CaO ...........

SrO. ...........

BaO ...........

MgO ...........

KaO.. .... ......

NaiO. ..........

LiiO ...........

K/) at 110° ....

H2 0 above 110°. 

P/\

COB .. ..........

803 ............

Cl .............

G.

62.58

.40

16.42

2.46

1.96

.08

2.47

.10

.41

1.84

3.91

4.57

.38 

1.40

00

.77

100. 08

H.

67.44

..32

15.78

1.58

.85

2.38

.09

.24

1.43

4.87

4.11

Trace.

.32 

.70 

.21

Trace.

Trace.

100. 32

I.

. 67.04

.20

15.25

1.69

1.13

0^

2.17

.03

.33

1.75

5.10

4.09

Trace?

.56 

.51 

.21

100. 11

J.

64.95

.39

15.44

2.02

1.60

3.07

.10

.35

2.65

3.87

4.25

.26 

.85 

.25

.02

.04

100. 11

K.

62.18

.55

15.77

1.83

2.44

4.13

.16

.43

3.55

3.91

3.92

.30 

.70

qo

.04

100. 23

L.

55.13

.74

20.27

1.52

4.29

iq

7.05

.06

.11

1.80

2.84

4.31

.14 

.95 

.40

.26

100. 00
CLARKE AND"! 

1IILLEBHAND.J IGNEOUS AND CRYSTALLINE ROCKS. 149

M, Minette, intrusive sheet, head of Sheep Creek. Chiefly biotite, 

augite, and orthoclase, with accessory apatite, plagioclase, quartz, and 

iron ore, and some secondary calcite, chlorite, and kaolin. Analysis 

by Hillebrand.

N. Monzonite, Yogo Peak. Described in Amer. Jouru. Sci., 3d series, 

vol. 50, p. 473, and 4th series, vol. 1, p. 356. Contains apatite, sphene, 

iron ore, pyroxene, hornblende, biotite, orthoclase, and oligoclase, and a 

little secondary kaolin. Analysis by Hillebrand.

O. Monchiquite, dike on Big Baldy Mountain. Contains much pyroxene, a few serpentinized olivines, iron ore, and apatite in a colorless 

base of analcite. Analysis by Hillebrand.

P. Monchiquite, dike on Bandbox Mountain. Contains olivine, augite, biotite, analcite, and apatite, with traces of serpentine and chlorite. 

Analysis by Stokes.

Q. Shonkinite, Yogo Peak. Described in Anier. Journ. Sci., 3d 

series, vol. 50, p. 474. Chiefly augite and orthoclase, with a considerable amount of accessory biotite, iron ore, and andesine, less apatite 

and olivine, and a trace of kaolin. Analysis by Hillebrand. 

Si02 ...........

Ti02 .. .........

Al,0;1 ....:.....

Cr2 03 ..........

Fcj03 ..........

FeO..... .......

NiO.... ........

MnO. ..........

CaO ...........

SrO...... ......

BaO ;..........

MgO. ..........

KoO. ..-...---..

Na3 0. ..........

Li.O ...........

H2 0 at 110° .... 

H2 0 above 110°. 

PB06 ...........

S03 . ...........

Cl .............

COs. .........

F ..............

M.

52. 26

.58

13.96

2.76

4.45

.14

7.06

.05

.23

8.21

3.87

2.80

Trace.

1.53 

1.34 

.52

.49

100. 25

N.

54. 42

.80

14. 28

Trace.

' 3. 32

4.13

.10

7.72

.13

.32

6.12

4.22

3.44

Trace.

' .22 

.38 

.59

100. 19

0.

48. 35

.52

13.-27

Trace.

.4.38

3. 23

.04

.19

9.94

.09

.54

8.36

3.01

3. 35

Trace.

.90 

2.89 

.40

.30

.25

100.01

P.

48.39

.73

11.64

.07

4.09

3. 57

Trace.

7.64

.15

.32

12.55

1 3.24

4.14

Trace.

.28 

2.56 

.45

.08

. 99.90

Q.

48.98

1.44

12.29

Trace.

2.88

5.77

.08

9.65

.08

. 43

9.19

4.96

2.22

Trace.

.26 

.56 

.98

.22

99,99
150 ANALYSES OF ROCKS AND ANALYTICAL METHODS. lBtrrx.148.

4. THE CASTLE MOUNTAIN DISTRICT.

Bocks described by Weed and Pirsson in Bull. 139. Analyses made 

by Pirsson in the laboratory of the Sheffield Scientific School.

A. Rhyolite, between Four-mile and Five-mile creeks, near Smith 

River. Contains quartz, soda-orthoclase, tourmaline, and a little iron 

ore and zircon.

B. Quartz-tourmaline-porphyry, upper Four-mile Creek. Contains 

quartz, orthoclase, plagioclase, tourmaline, fluorite, and a little white 

mica, apatite, and zircon.

C. Granite, Elk Peak. Contains quartz, orthoclase, oligoclase, biotite, hornblende, iron ore, apatite, sphene, and zircon. The last three 

minerals are rare.

D. Quartz-porphyry, sheet on ridge between Four-mile and Checkerboard creeks. Contains quartz, plagioclase, an uutwinned feldspar 

and biotite, with occasional grains of iron ore and crystals of apatite 

and zircon. . ' 

E. Ehyolite-pitchstone, forks of Checkerboard Creek. Essentially 

glass, inclosing grains of iron ore.

F. Aplitic granite, dike between Blackhawk and Eobinson. Contains quartz and unstriated feldspar, some plagioclase, and occasional 

biotite.

G. Quartz-porphyry, Musselshell Canyon. Contains quartz, biotite, 

plagioclase, apatite, iron ore, and zircon.

SiOj.. ......

Ti04 .......

AlaOs.......

FeA ......

FeO........

MnO. ......

CaO.........

MgO. ......

K»O........

.NaaO.......

Li,O.......

H2O........

Sp. gr......

A.

74.90

.15

13.64

.66

.50

Trace.

.61

Trace.

4.64

4.22

Trace.

.33

99.65 

2.61

B.

74.82

.25

13.80

.37

.30

Trace.

.17

.10

4.81

4.33

Trace.

.83

99.78 

2.59

«

C.

72.48

.32

13.14

I

np 

.00

1.02

Trace.

1.04

.15

4.88

4.22

.'42

99.33 

2.62

D.

72.38

.10

14.71

1.09

- .82

Trace.

.67

.70

4.15

4.28

.92

99.82 

2.61

E.

72.56

.20

12.33

.80

.82

Trace.

Trace.

3.08

5.36

4,59

99. 74 

2.37

F.

72.88

.45

12.90

.74

1 f)K

.05 '

.81

.75

5.03

3.72

1.22

99.60 

2.64

G.

71.67

.10

15.82

1.18

.35

Trace.

.25

.13

4.45

4.46

1.21

99.62 

2.60
CLAHKE AND") 

HILLEBIiAND.J IGNEOUS AND CRYSTALLINE ROCKS. 151

H. Feldspar-porphyry dike, below Castle. Contains orthoolase, less 

plagioclase, hornblende, biotite partly altered to chlorite, sometimes 

allanite, and occasional iron ore, apatite, and zircon.

I. Rhyolitic tuff, near forks of Checkerboard Creek. Contains fragments of shale, quartz, plagioclase,- sanidine, arid hornblende, in a 

brownish material carrying pumiceous glass. Much decomposed, with 

formation of kaolin.

J. Syenitic mass included in granite, head of Cottonwood Creek. 

Contains orthoclase, plagioclase, quartz, hornblende, biotite, apatite, 

and iron ore. A hprnblende-mica-syeuite.

K. Diorite, between Blackhawk and Robinson. Contains plagioclase, 

orthoclase, quartz, biotite, diallage, hypersthene, iron ore, apatite, and 

zircon.

L. Basalt, Volcano Butte. Contains labradorite, augite, olivine, a 

little serpentine, occasional quartz grains, small patches of glass, iron 

ore, chiefly ilmenite, apatite, a trace of calcite, and a mineral which 

may be nephelite or analcite.

M. Augite-vogesite, dike on west side of upper Four-mile Creek. 

Contains augite, hornblende, iron ore, a little plagioclase, orthoclase, 

calcite, and some decomposition products.

JS". Monchiquite-like dike rock, west side of upper Willow Creek. 

Contains augite, olivine, biotite, ilmenite, and a colorless base which 

appears to be partially zeolitized glass. Also a little serpentine, 

chlorite, and calcite.

In analysis L the symbol X refers to unseparated rare earths bimetallic acids, such as columbic, tantalic, etc.

Si02 .......

TiO, .......

x.. ........

A13 03 .......

Fe.2 0:! ......

FeO........

MnO .......

CaO .......

MgO .......

K2 0. .......

NasiO. ......

Li2 0 .......

HaO........

P205 .......

CO3 . .......

Sp.gr......

H.

65.87

.37

16.82

1.58

1.23

2.65

1.54

3.15

4.72

1.43

99.36 

2.62

I.

61.21

.56

15.67

4.06

.62

.10

2.18

1.58

2.75

1.57

Trace.

10.20'

100. 50

J.

61.87

.87

17.26

2.35

2.43

.03

3.23

1.82

3.83

5.18

Trace.

1.07

99.94 

2.67

K.

56.80

.46

18.30

1.64

5.58

5.31

3.63

3.28

4.35

.53

99.88 

2.83

L.

46.52

2.98

.73

10.48

4.40

7 7Q

.11

9.49

10.58

1.55

" 3.12

1.79

.83

100. 37 

2.99

M.

45.15

2.80

15. 39

' 2.76

5.64

.14

8.83

6.38

 2.77

2.67

2.85

.56

4.27

100. 21 

2.70

N.

42.46

2.47

.12.04

3.19

5.34

.16

12.14

12.40

2.68

1.21

4.03

.84

.55

99.51 

2.94
152 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

5. THE HIGHWOOD MOUNTAINS.

Eocks collected by W. H. Weed and L. V. Pirsson, who furnish the 

petrographic data. Analyses made in the laboratory of the Sheffield 

Scientific School, under the direction of Professor Pirsson.

A. Trachy-andesitic breccia, head of north fork of Willow Creek. 

Contains hornblende, biotite, iron ore, apatite, plagioclase, and orthoclase, with a little kaolin and limonite. B. B. Hurlbut and B. Barnes, 

analysts.

B. Trachyte, dike, 1 mile north of divide in Highwood Gap. Contains abundant phenocrysts of orthoclase and augite in a groundmass 

of the same minerals. Also a little biotite, apatite, and iron ore, and 

some secondary kaolin. B. B. Hurlbut, analyst.

C. Trachyte, dike, north end of South Mountain. Contains phenocrysts of alkali-feldspar, aegirine-augite and melanite, in a groundmass 

of alkali-feldspar. Apatite, iron ore, a trace of calcite, and some kaolin 

are also present. H. W. Foote, analyst.

D. Trachyte, dike, Aspen Creek. Contains alkali-hornblende and 

alkali-feldspar phenocrysts, in a groundmass of alkali-feldspars. Also 

some apatite and iron ore. Eock stained by limonite. H. W. Foote, 

analyst.

E. Trachyte, dike, head of Shonkiu Creek. Contains augite, biotite, 

iron ore, and orthoclase, in a groundmass of alkali-feldspar. Also 

apatite and some kaolin. W. M. Bradley, analyst.

SiOa ... .........

Ti02 ...........

A12O3 . ..........

FeA ..........

FeO ...........

MnO ...........

CaO. ...........

SrO ........ ....

BaO..... .......

MgO ...........

K2O.... ........

Na2 0.. .........

HoO.... ...*.....

P2 05 ...........

S03 - ............

C03 ............

C1-... ..........

Less O .........

A.

59.24

.22

13.84

5. 46

1.36

- 5.60

4.79

4.22

3.13

2.02

r .34

.08

.04

100. 34 

.01

-100.33

B.

58.04

.30

17.24

2.49

1.24

3.50

Undet.

Undet.

1.79

10.06

3.37

1.95

.22

.38

100. 58 

. 09"

100. 49

C.

57.18

.30

18.54

3.65

1.15

2.31

Trace.

.49

.69

8.58

4.48

2.10

.05

.06

.77

100. 35 

.17

100. 18

D.

55.23

.42

18.31

4.90

2.06

Trace.

3.62

Trace.

.46

' 1.85

6.43

4,02

1.84

.58

.23

.32

100. 27 

.08

100. 19

E.

51.94

.39

15.78

4.07

3.17

6.04

.28

.42

3.48

7.69

3.44

2.17

.59

.29

.08

99.83 

.02

99.81
CLAEKB AND! 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE EOCKS 153

F. Syenite^ top of Palisade Butte. Contains augite, iron ore, apatite, alkali-feldspar, a little biotite, some limonite in cracks, much 

natrolite, and possibly other zeolites. H. W. Foote, analyst.

Gr. Leucite-syenite, head of Davis Creek. Contains augite, iron ore, 

olivine, biotite, 'apatite, alkali-feldspar, leucite, and some zeolites, with 

traces of limonite and serpentine. E. B. Hurlbut, analyst.

H. Monchiquite, dike east side of Highwoocl Gap. Contains augite, 

olivine, biotite, iron ore, apatite, and analcite, with some serpentine and 

a little kaolin. H. W. Foote, analyst.

I. Leucite-basalt, saddle between Highwood and Pinewbod peaks. 

Contains augite, iron ore, leucite, apatite, altered olivine, chlorite, calcite, and zeolites. H. W. Foote, analyst.

J. Leucite-basalt or leucite-monchiquite, dike on Arrow Peak. 

Phenocrysts of augite, olivine, and biotite, with some leucite, in a 

groundmass of the same minerals. Also analcite, iron ore, and apatite, 

H, W, Foote, analyst.

Si02 ...........

TiOs ...........

AloOa... ........

Fe,0; ..........

FeO ...........

MnO. ..........

CaO ...........

SrO...... ......

BaO ...........

MgO. .......... O

K2O ...........

Na*O ...--.....

HaO...... ......

P206 ...........

so3 ............

COS .. ..........

01 .............

F.

50.11

.82

17.13

3.73

3.28

Trace.

5.09

.35

.63

2. 47

7.47

3.72

4.47

.67

.08

.07

100. 09 

.02

100. 07

 G.

49.59

.36

14.51

3.51

5.53

Trace.

9.04

.21

.49

6.17

5.60

3.52

1.95

.15

.02

.13

100. 78 

.03

100. 75

H.

47.82

.67

13.56

4.73

4.54

Trace.

8.91

.21

.16

7.49

3^23

4.37

3.37

1.10

.04

100. 20 

.01

100. 19

I.

47.98

.58

13.34

4.09

4.24

Trace.

9.32

.14

.50

7.01

5.00

3.51

2.10

1.03

TraceT

1.24

.21

100. 29 

.07

100. 22

J.

46.04

.64

12.23

3.86

4.60

Trace.

8.97 '

.25

.48

10.38

5.77

2.42

2.87

1.14

.11

99.76 

.03

99.73
154 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [B0LL.148.

K. Missourite, head of Shoukin Creek. Described in Amer. Journ. 

Sci., 4th series, vol. 2, p. 315. Contains apatite, iron ore, olivine, biotite, 

augite, and leucite, the tw.o latter being the chief minerals. Some 

zeolites and analcite are also present. -E. B. Hurlbut, analyst.

L. Pseudo-leucite-syenite, head of Shoukiii Creek. Contains augite, 

olivine, biotite, iron ore, apatite, orthoclase, nephelite, zeolites, and 

traces of serpentine, limouite, and kaolin. Contains pseudomorphs 

after leucite. E. B. Hurlbut, analyst.

M. Monzouite, Highwood Peak. Contains augite, biotite, iron ore, 

apatite, plagioclase, and alkali-feldspar. E. B. Hurlbut, analyst.

N. Monzouite, Middle Peak. Contains augite, olivine, biotite, iron 

ore, apatite, plagioclase, and orthoclase. The two latter, with augite, 

are the chief minerals. E. B. Hurlbut, analyst.

Si02 . .............

TiO, .............

A12 03 . ............

FeaO:! ............

FeO.. ............

MaO.... .........

CaO. .............

SrO... ...........

BaO...... ........

MgO. ...... ......

K20.... ..........

Na.0...... .......

HSO...... .....:..

P

f\ 2U5 .............

S03 ..............

Cl ...............

K.

46.06

 .73

10.01

3.17

5.61

10.55

.20

.32

14.74

5.14

1.31

1.44

.21

.05

.03

99.57 

.01

99.56

L.

51.75

.23

14.52

5.08

3.58

Trace.

7.04

.07

.30

4.55

7.61

2.93

2.25

.18

.05

100. 14 

.01

100. 13

M.

51.00

10

17.21

2.41

4.23

q IK

.14

.34

6.19

d Q3

2.88

.63

.33

03

99.60

N.

52.05

' .47

15.02

2.65

5.52

Trace.

8.14

.28

.42

5.39

6.10

3.17

.35

.21

no

.24

100.03 

.06

99.97

The following rock and separations, from Square Butte, at the east 

end of the Highwood Mountains, are described by Liudgreu in Amer. 

Journ. Sci., 3d series, vol. 45, p. 286. Analyses by W. H. Melville, 

record No. 1268.

A. Post-Cretaceous sodalite-syenite. Contains orthoclase, some 

albite, hornblende, sodalite, analcite, and apatite. Orthoclase predominates. The sodalite amounts to 8 per cent.

B. Hornblende separated from A. Near barkevikite.

C. Sodalite from A. Sp. gr. 2.265.
d-ARKE AND"] 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 155

D. Analcite from A. Sp. gr. 2.255.

In addition, the orthoclase gave 3.88 per cent Na2O and 11.03 K2O. 

A separation of mixed feldspars, sp. gr. 2.56, gave 6.08 Na2O and 8.91 

K20.

SiO, .............

TiOa .............

AljOs- ...........

Fe2O3 .....!......

FeO..............

NiO... ...........

MnO.............

CaO..............

MgO............. O

KaO. .............

Na,0. ............

HaO at 100° ......

H20 above 100°... 

P206 .............

Cl ...............

n

A.

56.45

.29

20.08

1.31

4.39

Trace.

.09

2.14

.63

7.13

5.61

 .26

1.51 

.13

.43

100. 45 

.10

100. 35

B.

38.41

17.65

' 3.75

21.75

Trace.

.15

10.52

2. 54.

1.95

2.95

.24

99.91

C.

41. 56

29.48

.49

49

.15

.91

19.21

.45

3.73

4.79

101. 26 

1.08

100. 18

D.

49.54

25. 07

.40

.22

.20

.89

15.32

Undet.

Undet.

1.67

93.31 

1 .38

92.93

6. THE LITTLE ROCKY MOUNTAINS.

Granite-syenite-porphyry. Described by Weed and Pirsson, Jou.ru. 

of Geology, vol. 4, p. 399. Contains orthoclase, quartz, oligoclase, iron 

oxides, and a little iimscovite. Analysis by H. N. Stokes, record No. 

1558.

SiO* .............

TiOa .............

AlaOa....... ......

FesOs ............

FeO.... ..........

MnO ..............

CaO....... ........

SrO ...............

BaO. .............

MgO .............

KaO.. ............

68.65

.20

18.31

.56

.08

r Pl»o/»p

1 no

.10

.13

.12

4.74

NasO. ............

Li«0 .............

HsOatllO0 .......

H.2O above 110°...

PaOr, .............

S03 ..............

Cl ...............

F ................

4.86

.27

.83

.03

99.88
156 ANALYSES "OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

7. THE BEAKPAW MOUNTAINS.

Described by Weed and Pirsson, Amer. Journ. ScL, series 4, vol. .1, pp. 

283 and 351, and vol. 2, pp. 136 and 188. Analyses by H. N. Stokes, 

record Nos. 1558 and 1572.

A. Quartz-syeuite-porphyry, .from Gray Butte. Contains anorthoclase, microlites of plagioclase, aegirite, augite, quartz, and apatite, 

with an occasional zircon and very few biotite leaves.

B. Quartz-syenite, Beaver-Creek stock. Contains orthoclase, albite, 

quartz, augite, and iron oxides, with very little biotite, hornblende, 

and sphene. . C. Basic syenite or monzonite (yogoite), from Beaver Greek. Contains orthoclase, plagioclase, diopside, biotite, iron oxides, and apatite.

8iO»... .....................

TiO2 .......................

A1303 . ......................

FesjOa ......................

FeO.. ......................

MnO.... ...................

CaO. ...i. ..................

&TO:... ....................

BaO .......................

MgO... ....................

K2O.. ......................

Na20.. .....................

Li,0 .......................

H2 0 at 110° ................

H20 above 110°. ............

PSQ6 .........................

S03 ........................

Cl .........................

F.. ........................

A.

66.22

.22

16.22

1.98

.16

Trace.

1.32

.06

.29

.77

5.76

6.49

Trace.

.08

.24

.10

.02

.04

99.97

B.

68.34

.21

15.32

1.90

.84

.07

.92

.04

.08

.54

5/62

5.45

None.

.15

.30

.13

Trace.

.04

None?

99.95

C.

52.81

.71

15.66

3. 06

4.76

Trace.

7.57

.09

.24

4.99

4.84

3.60

Trace.

.16

.93

.75

Trace.

.07

100. 24
CLARKE AND"! 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 157

D. Shonkinite, Beaver Creek. Contains auprthoclase, diopside, biotite, iron oxides, and apatite, with very little oliviiie and probably a 

trace of nephelite.

E. Leucitite, Bearpaw Mountain. An olivine-free leucite-basalt. 

Contains leucite, augite, iron oxides, rarely biotite, and very little 

glassy base.

F. Tingnaite dike, Bear Creek. Contains orthoclase, nephelite, 

cancriuite, augite, tegirite, apatite, a little sodalite, and a doubtful 

fibrous hornblende.

G. Pseudo-leucite-sodalite-tiuguaite, Beaver Creek. Contains orthoclase, nephelite, sodalite, nosean, segirite, diopside, and fluorite.

SiOs .............

TiOs .............

A12O:,.. ...........

Crs03 ............

Fe2 03 ............

FeO.. ............

NiO.. ............

CoO .............

MuO.. ...........

CuO .............

CaO .............

SrO.. ............

BaO .............

MgO.... .........

KsO-.. ............

NasO.- ...........

Li2 0 .............

H2OiitllO° ......

H2O above 110°... 

P205 .............

so:J ...... ........

C02 . ..............

PI

F ................

D.

50.00

.73

9.87

.11

3.46

5.01

.07

8.31

' .07

.32

11.92

5.02

2.41

.17

1.16 

.81

.02

.31

.08

.16

100. 01 

.08

99.93

E.

46.51

.83

11.86

7.59

4.39

.04

.22

7.41

.16

.50

4.73

8.71

2.39

Trace.

1.10

2.45 

.80

.05

.04

Trace.

99.78 

.02

99.76

F.

57.46

.60

15.40

4.87

.87

' 2. 59

.16

.60

1.37

9.44

5.48

.09

.82 

.21

.13

.13

.20

Trace.

100. 42 

.05

100.37 -

G.

51.93

.20

20.29

3.59

1.20

1.65

.07

.09

.22

9.81

8.49

.10

.99 

.06

.67

.25

.70

.27

100. 58 

.27

100. 31
158 ANALYSES"OF KOCKS AND ANALYTICAL METHODS. [BULL. 148".

COLORADO. 

1. THE DENVER BASIN.

Eocks described by Cross, in Mon. XXVII. Analyses A, B, D, E by 

L. G. Eakins, C by W. F. Hillebrand. All but A were made in the 

Denver laboratory.

A. Dolerite, from a dike near Valinont. Contains augite, plagioclase, olivine, orthoclase, and biotite, with accessory magnetite and 

apatite. Eecord No.-1145.

B. Augite separated from A.

C. Basalt, Table Mountain, lower capping sheet. Contains plagioclase, orthoclase, augite, magnetite, and apatite, with olivine much 

serpentinized. Sp. gr. 2.83, 22.5°.

D. Basalt, earlier flow, south slope of North Table Mountain. Contains augite, olivine, plagioclase, probably orthoclase, magnetite,, apatite, and a.little biotite.

E. Augite-inica-syenite, from North Fork of Turkey Creek, Jefferson 

County. Contains orthoclase, augite, biotite, rhombic pyroxene, hornblende, plagioclase, quartz, apatite, and magnetite. Sp. gr. 2.857, 

29.5°. "

SiO, ...........

Ti02 ...........

A12 03 ..........

Fe3O3 ........... 

FeO;.. .........

MnO.... ....... 

CaO ...........

BaO ...........

MgO.... ....... O

K2O.... ........

Na.3 0. ..........

H2 0. ...........

P205 ...........

Cl .............

S03 . ........

A.

48,25

.89

16.73

3.99 

"6.28

 Trace. 

8 39

.01

5.77

4.08

3.24

1.72

.68

.08

. 12

100. 16

B.

49.10

7.95

8.30

22.54

12.37

100.26

C.

52.59

. 84.

17.91

3.81 

5.18

Trace. 

7.24

4.11

3.83

2.94

1.24

.14

OK

99.88

D.

AQ fiO

.85

18.06

2.64

fi 1Q

.13

'8.24

5.73

3.90

2 QQ

Q1

.81

iq

100. 27

E.

56.90

19

18.50

.17 

4.61

Trace. 

6.17

5.10

4.14

2 QQ

.51

7Q

TVnpA

100: 07
CLABKE AND"! 

HILLEBBAND.J IGNEOUS. AND CRYSTALLINE ROCKS. 159

The following rocks from the Denver Basin were analyzed by L. G. 

Eakins in the Denver laboratory, but the analyses do not appear in the 

monograph. The subjoined data have been supplied by Whitman 

Cross.

A. Enstatite-diabase-porphyry, Mount Morrison. Contains labradorite and enstatite in a groundmass of considerable amount, which 

is colorless and cryptocrystalline, probably feldspathic, and carries 

magnetite and other indistinct ferritic matter.

B. Augite-andesite, Table Mountain. Contains plagioclase (andesine), with rare augite and biotite, in a groundraass of plagioclase, 

augite, magnetite, and minor accessories. This rock contained ptilolite 

in its vesicular equivalent. Described in Proc. Colorado Sci. Soc., 1886, 

p. 72.

C. Augite-andesite, a pebble from the Denver beds, Table Mountain. 

A few augite and andesite phenocrysts in a groundmass of oligoclase, 

orthoclase, and quartz (?) grains, with some augite and magnetite.

SiOa .................

A12O3 . ................

Fe3 03 ..........'......

FeO. .................

MnO. ................

CaO .................

MgO.. ...............

K8O... .......;.......

NagO.... .............

HjO... ...............

P20fi .................

A.

56.74

18.80

.15

6.91

.07

7.34

5.57

.77

2.32

1.09

.20

99.96

2.876, 27°

B.

59. 26

23.63

.30

.57

5.93

.31

4.78

4.94

.74 

100. 46 

2.625, 31°

0.

59.29

21.27

3.33

1.04

'.21

5.25

1.12

3.00

3.39

1.63

.23

99.76 

2.596,14°°.5

2. THE PIKES PEAK DISTRICT.

-/

First, granite, described by E. B. Matthews for a forthcoming publication of the Survey. Analyses by W. P. Hillebrand, record IsTo. 1470.

A. Granitite, Sentinel Point, western part of Pikes Peak massif. 

Contains niicrocline, microcline-perthite, quartz, biotite, a little oligoclase, and accessory fluorite, apatite, zircon, sphene, magnetite, and 

allanite.

B. Granitite, near road between Elorissant and the Platte Eiver. 

Consists chiefly of microcline in perthitic intergrowth with albite, 

quartz,'and biotite.
160 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

C. Porphyritic granitite, south side of Pikes Peak, ridge between 

Middle and North Beaver creeks. Contains microcline, perthite, orthoclase, oligoclase, quartz, biotite, and accessory apatite, fluorite, zircon, 

and magnetite.

D. Sheared granite, Currant Creek Canyon, north of Twelve-mile 

Park. Contains perthitic microcline, quartz, muscovite, and sericitic 

aggregates replacing plagioclase and a part of the microcline.

E. Granite, Currant Creek Canyon, north of Twelve-mile Park. 

Consists chiefly of perthitic microcline, quartz, greenish biotite, muscovite, and plagioclase altered to a sericitic mass. Also flakes of 

limonite. Accessory minerals rare.

F. Granitite, Middle Beaver Creek, south side of Pikes Peak. Contains microcline, orthoclase, perthitic albite, oligoclase, abundant quartz, 

biotite, and a little accessory magnetite, fluorite, and zircon.

G. Granite-gneiss, north of Twin Creek. Contains microcline, orthoclase, quartz, biotite, abundant fluorite, and a little sphene and apatite.

SiO2 ...........

Ti03 ...........

A12 03 ..........

Fe3O3 ..........

FeO...... ..I...

MnO. ..........

CaO ...........

SrO.. ..........

BaO ...........

MgO. ..........

K2 0.. ........ ...

NajO. ..........

Li2 0 ......*.....

H2OatllO°..'... 

H20 above 110°. 

P2 06 - ..........

F...... ........

GO*.. ..........

A.

77.03

.13

12.00

.76

.86

Trace.

.80

None.

Trace.

.04

4.92

3.21

Trace.

.14 

.30 

Trace.

.36

1.00. 55 

.15

100. 40

B.

75. 92

.05

12.96

'.33

1.40

.04

.15

None.

Trace.

Trace.

4.15

4.60

.16 

.32 

Trace.

.12

.03

100. 23 

.05

100. 18

C.

75.17

.10

12.66

.23

1.40

Trace.

.82

Trace?

.03

.05

5.75

2.88

Trace.

.16 

.66 

.03

.31

100. 26 

.13

100. 13

D.

74.40

.12

14.43

.89

.22

Trace.

.58

None.

Trace.

.07

6.56

1.76

Trace.

.15 

.92 

.22

.04

100. 36 

.02

100. 34

E.

73.90

.07

13.65

.28

.42

Trace.

.23

'None.

Trace.

.14

7.99

2.53

Trace.

.16 

.33 

.05

None.

99.75

F.

73.51

- .18'

13.28

.94 '.97

1.11

None.

Trace.

.05

5.22

3.79

.16 

.62 

Trace.

.55

100.38 

.22

100.16.

G.

66.90

.43

14.86

.93

3.41

.15

1.23

None.

.14

01

5.02

5.56

.06

.16 

.31 

.12

1.00

100. 59 

.42

100.17

Second, rocks of the Cripple Creek district, described by Cross. 

Descriptions published, except when otherwise stated, in 16th Ann., 

Part II, pp. 38-50. Analyses, with two exceptions, which are properly noted, by W. F. Hillebrand, record Nos. 1448, 1453, and 1524.
CLARKE AND"] 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 161

A. Pkonolite, dike in granite northeast of Big Bull Mountain. Contains anorthoclase, nepheline, sodalite, a3girine-augite, some segirine, 

biotite, magnetite, and limonite. Nosite not distinguishable.

B. Phonolite, Mitre Peak. Contains sanidine, nepheline, sodalite, 

segirine, nosite, and colorless particles which may be lavenite.

C. Phonolite, from a hill one mile south of Straub Mountain. Contains anorthoclase, sanidine, nepheline, sodalite, nosite, analcite, and 

segirine, with, sometimes segirine-augite.

D. Phonolite, Khyolite Mountain. Contains nepheline, nosite, analcite, iBgirine, and some tegirine-augite, in a feldspathic groundmass. 

Sp. gr. 2.52, 23°.

E. Phonolite from between Florissaut and Manitou. Analysis by 

L. G. Eakius, made in the Denver laboratory, inserted here for comparison with the Cripple Creek samples. Described by Cross in Proc. 

Colorado Sci. Soc., vol. 2, p. 167. Contains sanidine, nepheline, hornblende with accessory pyroxene (f), magnetite, apatite, and sphene. 

Sp. gr. 2.576, 13°.

F. The portion of E. soluble in hydrochloric acid. This portion 

amounted to 25.39 per cent, and is reduced here to 100. Analysis also 

by Eakins.

SiOa ..-« . -.

Ti02 ...........

ZrO2 ...........

A1203 .... .......

Fe.;03 ..........

FeO.. ..........

MnO.... .......

CaO. ...........

SrO ....... ......

BaO.... ........

MgO ...........

KaO.. ..........

Na2O. ..........

Li2 0 ...........

H2OatlOO° ....

H20 above 100°.

P8 0« .... .......

S03 .. .......

Cl .............

coa .... ........

A.

59.00

.29

.20

20.07

1.58

.65

.12

1.05

None.

.10

5.63

8.34

.24

2.03

.05

.07

.24

.26

99.92

B.

58.98

.24

.20

20.54

1.65

.48

.26

.67

None.

.11

5.31

9.95

.19

.97

.04

.20

.28

100. 07

C. 

58.78

.29

.17

20.03

1.87

.49

.15

.83

None.

.16

5. 50

9.36

.31

1.57

.03

.12

.58

100. 24

D.

58.64

. .20

.09

19.62

2.17

.42

.20

1.24

Trace.

Trace.

.37

5.26

8.39

Trace.

.34

2.40

.03

Trace?

.14

.23

99.74

E.

60.02

20.98

2.21

.51

1.18

5.72

8.83

.70

Trace.

100. 15

F.

44.66

31.59

.95

2.25

2.13

18.42

100.00

Bull. 148 11
162 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

G. Trachytic phonolite, dike on west slope of Bull Cliff. Contains 

alkali-feldspars, nepheline, nosite, sodalite, augite, scanty segirine, 

brown'hornblende, magnetite, sphene, apatite, and sometimes lavenite.

H. Altered phonolite, Washington shaft, Victor. Contains potashfeldspars, with some alteration to muscovite. Crystals of pyrite and fluorite are visible, but nepheline and tegirine have disappeared. Analysis hitherto unpublished.

I. Nepheline-syenitej near the Longfellow mine. Contains alkalifeldspars, nejjheline, sodalite, augite, some segirine, hornblende, biotite, 

sphene, apatite, and magnetite. Sp. gr. 2.68, 23°.

J. Nepheline-basalt, Appie Ellen shaft. Much altered. Rich in olivine, augite, and magnetite. Also contains nepheline, feldspars in 

small amount, and biotite. Sp. gr. 2.99, 23°.

K. Altered nepheline-basalt, Anna Lee mine. Analysis hitherto 

unpublished and not discussed.

L. Local facies of a phonolitic mass, Bull Cliff. Contains abundant 

.augite, plagioclase, alkali-feldspar, magnetite, and a little red-brown 

biotite, with a colorless isotropic base in the darker spots. Analysis 

hitherto unpublished.

Si02 ...........

Ti02

Zr02 . ..........

A12O3 .. .........

Cr2O3 ..........

Fe2 0s ..........

FeO...... ......

MnO. ..........

CaO ...........

SrO ............

BaO ...........

MgO ...........

K,0...... ......

Na.2O.... .......

Li.O ............

H2 0 at 110° .... 

H2O above 110°. 

P2 0B ...........

S03 ............

Cl .............

F ..............

CO2 ...... ......

FeS2 ...........

G.

59.38

.58

.10

19.47

1.60

1.19

.15

1.96

.03

.13

.36

5.83

7.80

.11 

.69 

.08

.37

.22

100. 05

H.

'56.74

.58

.07

20". 30

1.06

None.

.57

Trace.

.19

.23

13.36

.62

Trace.

.33 

1.15 

.25

Undet.

4.65

100. 10

I.

54.34

1.09

.07

19.23

3.19

2.11

.08

4.53

.16

.24

1.28

5.14

6,38

Trace.

.14 

1.17

.27

.07

.28

Undet.

99.77

J.

35.03

2.20

9.80

5.55

4.98

.06

15.09

.17

.14

9.78

2.16

2.04

Trace.

.41 

2.05 

1.99

Undet.

7.83

.38

99.66

K.

48. 61

3.57

20.74

4.29

.22

None.

.25

None.

None.

2.11

.77

1 ir } - 16

12.10 

7.07 

.29

.63

100. 81

L.

49.84

1.43

.03

17.78

5.86

2.62

.21

7.35

.18

.22

3.02

3.04

5.20

.34 

2.02 

.76

Undet.

.52

100. 42
CLAEKE AND") 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 163

Third, miscellaneous rocks in the Pikes Peak .district. Analyses, 

hitherto unpublished, by W. E. Hillebrand, record Nos. 1448,1453, and 

1669. Petrographic data supplied by Whitman Cross. Names marked 

with a query are provisional designations only.

A. Trachyte? Near Bobbins' ranch. Has scattered phenocrysts of 

alkali-feldspar, oligoclase, and biotite in a predominant trachytic 

groundinass of alkali-feldspar, tridymite, particles of residual glass, and 

ferritic flakes and grains.

B. Trachyte? Wicher Mountain. Shows biotite and a few glassy 

feldspars in a groundmass resembling that of A.

C. Audesite? Bare Hills. Composed mainly of plagioclase and 

alkali-feldspar, with small augites and much ferritic matter. Minute 

prisms of a yellowish-brown arnphibole (?) and scales of tridymite are 

also visible.

D. Pyroxene-audesite? Wicher Mountain. Contains phenocrysts of 

plagioclase, a few of augite, minute specks of iddingsite, and flakes of 

limonite. In the groundmass are plagioclase, orthoclase (?), augite, 

iddingsite, and hypersthene. In the pores tridymite appears.

B. Plagioclase-basalt? Mesa east of Mac Gulch. Contains plagioclase, augite, olivine, iddingsite, magnetite, biotite, and apatite.

F. Plagioclase-basalt, Saddle Mountain. * Phenocrysts of augite and 

oliviue in a groundmass of plagioclase, orthoclase, augite, magnetite, 

biotite, and apatite. Yery fresh.

SiOa.... ........

Ti02 ...........

Zr02 ...........

A12 03 ... ........

re.2 o3 ..........

FeO.... ........

MnO.... .......

CaO... .........

SrO .......... ~

BaO... .........

MgO ...........

K2 0... .........

NasO... ........

H3OatlOO° .... 

HjO above 100°. 

P305 ...........

SO:, ............

COa... - ........

A.

69.52

.23

.05

15.44

1.90

.09

.08

1.70

.04

.19

.17

5.04

4.54

.33 

.27 

.14

.17

99.90

B.

66.12

.29

.06

17.21

2.43

.08

2.11

.05

.25

.35

5.57

4.70

.14 

.71 

.11

100. 18

C.

62.64

.59

.08

17.82

3.91

.31

.04

3.22

.07

.28

.47

4.99

4 47

.58 

.65 .

.25

100. 37

D.

57.48

 i.oo

.04

18.04

5.73 '

.73

5.03

.12

.20

1.17

4.15

4.28

.62 

.55 

.66

.16

99.96

E.

52.97

1.04

.05

18.31

1.86

6.73

.09

6.51

.14

.18

3.04

3.35

3.74

.44 

.31 

.81

99.57

P.

48.76

1.65

15.89

6.04

4.56

.13

8.15

.06

.17

5 OS

o qq

3.43

 .40 

1.48 

.60

100. 23
164 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

G. Analcite-basalt from the Basin. Contains phenocrysts of augite, 

olivine, and analcite. Also' magnetite, with subordinate amounts of 

alkali-feldspars, biotite, and apatite.

H. Portion of the analcite-basalt soluble in hydrochloric acid.

I. Augite separated from G.

J. Analcite separated from G. After deduction of 4;22 per cent of 

substance insoluble in boiling, dilute hydrochloric acid, and la.ter 

removal of liberated silica with weak potash solution. Sixty-two one 

hundredths per cent of the water goes off over sulphuric acid. A 

trace of lithia was found.

SiO2 .............

Ti02 .............

ZrOa ..........

A1ZO3 . ............

Fe2 03 ............

FeO.. ............

MnO .............

CaO. .............

SrO .......... ....

BaO...... ........

MgO. ............

K2O.... ..........

Na.,0. ............

H2OatlOO°.......

H,0 above 100°... 

PaOs ... ...........

Cl.... ............

G.

45. 59

1.32

.03

12,98

4.97

4.70

.14

11.09

.12

.13

8.36

1.04

4.53

.51

3.40 

.91

.05

99.87

H.

44.44

"20. 11

1 7.50

J 

3.94

.16

?

5.81

1.13

8.17

| 7.91

.10

99.27

I.

49.26

1.53

6.01

3.31

4.23

Undet.

21. 79

.06

?

12.40

.41

.79

Undet.

Undet.

99.79

J.

51.24

24.00

-i 1.20

1.62

.06

.33

1.25

11.61

| 9.09

100. 40

* Includes PA-
CLARKE AND"] 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

3. SILVER CLIFF AND ROSITA.

165

Eocks described by Cross, mostly in 17th Ann., Part II, p. 263. Also, 

partly, in Proc. Colorado Scientific Soc., vol. 2, p. 228. Analyses by 

L. G. Eakius. Those with record numbers attached were made in the 

Washington laboratory j all others in the laboratory at Denver.

A. Peridotite, Cotton wood Gulch. Contains hornblende, biotite, 

hypersthene, olivine, a little plagioclase, apatite, pyrrhotite, and sillimanite (*?).

B. Augite-diorite, Mount Fairview, Eosita Hills. Contains augite, 

biotite, labradorite, and accessory orthoclase, olivine, magnetite, and 

apatite. Sp. gr. 2.870, 32°. Olivine a subordinate constituent.

O. The same as B, but with orthoclase in much larger amount. Sp. 

gr. 2.768, 34°. Eecord No. 1091.

D. Trachyte, Game Eidge. Contains sanidine, plagioclase, a little 

biotite, magnetite, apatite, and zircon, in a groundraass of orthoclase 

with a little quartz. Sp. gr. 2.592, 29°.

B. Trachyte from a dark-colored dike. Contains more magnetite 

than "D, but otherwise the two are practically identical. Sp. gr. 

2.621, 240.

Si(V ...........

Ti02 ...........

AU>3 . ..........

Fe203 ..........

FeO...... ......

MnO...........

CaO ...........

MgO. ..........

KaO ............

NasO. ..........

H3O.. ..........

P206 ...........

C09 .... ........

ci .............

A.

46.03

Q O7

2.72

9.94

.40

3.53

25.04

.87

1.48

.64

.17

100. 09

B.

50. 47

.51

18.73

4.19

4.92

.11

8.82

3.48

3.56

4.62

.58

.10

Trace.

100. 09

C.

53.80

.43

20.13

3.57

2.63

.29

5.60

2.26

4.49

5.20

.90

.56

99.86

D.

66.03

18.49

2.18

.22

Trace.

.96

.39

5.86

5.22

.85

.04

Trace.

100.24

E.

65.41

18.78

.94

.72

Trace.

1.58

.16

5.41

5.91

1.38

100. 29
166 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Andesite, Pringle Hill. Contains plagioclase, orthoclase, quartz, 

biotite, augite, magnetite, and apatite, with sometimes a little hornblende. Sp. gr. 2.651, 170.8. Eecord No. 1124.

Or. Pringle anclesite dike. Like F, but often contains sphene. Sp. 

gr. 2.690, 28°.

H. The Bunker andesite. Contains plagioclase, orthoclase, augite, 

biotite, hornblende, quartz, magnetite, and apatite. Sp. gr. 2.699, 34°. 

Eecord No. 1091. From Lookout Mountain.

I. Altered Bunker andesite from Eobinson Plateau. Biotite gone, 

magnetite altered to limonite, feldspars not much attacked. Eecord 

No. 1124. Sp. gr. 2.580,19°.7.

J. Much decomposed Bunker andesite from ridge near Knickerbocker 

Hill. Augite, hornblende, and biotite all replaced by decomposition 

products, plagioclase much muscovitized. Eecord No. 1124.

SiOB ... .........

Ti02 ...........

AlsOa. ..........

Fe2O3 ..........

FeO...... ......

MnO ...........

CaO. ...........

MgO ...........

K8O.. ..........

Na.2O. ..........

HaO.. ..........

P20ft ...........

CO8 ... .........

F.

58.94

.27

17.19

2.63

1.98

.10

4,45

1.52

3.90

4.20

4.53

.23

99.94

a.

63.49

18.40

2.44

1 OQ

 .16

2.30

.66

4.62

5.70

1.04

Trace.

Trace.

99.90

H.

57.01

.27

18.41

q fiQ

9 3ft

.21

4.29

2.34

3.72

4- Q1!

2.29

.42

99.96

I.

63.88

19.96

2.21

K7

2.03

.58

3.88

4,19

2.63

99.93

J.

67.13

30

18.41

.45

.07

.44

5.28

4.17

2.98

Trace.

99. 78
CLARK E AND") 

HILLEBRAND.J IGNEOUS AND CEYSTALLINE JtOCKS. 167

K. Dacite, Bald Mountain, near Eosita. Contains plagioclase, biotite, hornblende, sometimes augite, magnetite, and quartz. Sp. gr. 

2.574, 24°. Record No. 1068.

L. Mica-dacite. Contains plagioclase, sauidine, biotite, and quartz. 

Sp. gr. 2.563, 24°. Record No. 1068.

M. Rhyolite, Pennsylvania Hill. Sp. gr. 2.470, 26°. Record No. 1079.

N. Rhyolite, Round Mountain. Contains sanidine, quartz, some 

glass, and accessory garnet.

O. Rhyolite, Silver Cliff. Sp. gr. 2.56Q, 15°. Record No. 1125.

SiOa.. ..........

Ti02 ...........

A12 03 .. .........

Fe3 0:) ..........

FeO.. ..........

MnO. ..........

CaO...... .......

MgO. ..........

K3 0 ............

Na3 0. ..........

HoO...... ......

P205 . ..........

K.

66.46

17.91

2.42

.35

2.89

.49

3.74

4.79

1.01

100.06

L.

fi7 4.Q

17.76

2.54

.08

1.67

.35

4.40

5.03

.52

99.84

M.

70 87

15.18

2.18

.12

1.58

.60

5.04

3.47

1.08

100. 12

N.

7e on

12.96

.37

.27

.03

9Q

.12

8.38

2.02

.58

100. 22

0.

7X on

TflPA

13.65

.38

.18

.14

.51

.15

6.81

1.84

1.13

100. 18
168 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

P. Ehyolitic tuff. A lake-bed deposit, east of the Blue Mountains. 

Mainly composed of glassy rhyolite dust.

Q. Devitrifted pitchstone, the gangue of ptilolite. Shows feldspar, 

quartz, and barite. Described by Cross and Eakins in Amer. Journ. 

Sci., 3d series, vol. 44, p. 96. From 3 miles southeast of Silver Cliff. 

Eecord No. 1342.

E. Pitchstone, Eosita. Eecord No. 1033.

S. Pitchstone, Fleetwood Tunnel, Silver Cliff.

T. Alteration product of S. Consists mainly of silica and kaolin. 

Eecord No. of S and T, 1034.

SiOs ...........

A12O3 ..........

Fe2O3 ..........

FeO... .........

MnO. ..........

CaO ...........

BaO ...........

MgO. ..........

KaO. ...........

Na2O. ..........

H2O.. ..........

P»06 . ..........

SO3 ............

p.

71.02

14.27

1.22

1.38

Trace.

3.97

2.28

6.12

100. 26

Q.

65.67

13.48

1.51

Trace.

2.41

.32

.31

2.42

1.52

12.27

Trace.

.28

100.19

E.

73.11

13.16

.62

00

.14

.54

19

5.10

2.85

4.05 

99. 99

S.

71.56

13.10

.66

.28

.16

.74

.14

4.06

3.77

5.52

99.99

T.

71.71

12.36

1.10

.17

1.11

1.21

.36

.17

n Q7

100. 16
CLARKK AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 169

U. Syenite, Silver Cliff. Contains orthoclase and plagioclase in 

nearly equal amounts, colored by ferric hydroxide, with amphibole, a 

little biotite, and secondary epidote, calcite, and chlorite. Sp. gr. 

2.689, 2Qo.

Y. Quartz-alunite rock, Democrat Hill. About two-thirds quartz 

and one-third alunite. Eecord No. 1126.

"W. The same, Mount Eobinson. About one-fourth alunite. Eecord 

No. 1248.

X. Quartz-diaspore rock, Mount Eobinson. About 18 per cent 

diaspore, the rest quartz. Eecord No. 1167.

Eocks Y, W, and X are also described in Amer. Journ. Sci., 3d 

series, vol. 41, p. 471. These three rocks are decomposition products 

of rhyolite.

Si02 ....... .......

TiOa .............

A12O3 ....... ......

FesOs ............

FeO. .............

MnO. ............

CoO.. ............

BaO...... ........

MgO. ............

K20...... ........

NtoO. ............

H20. .............

P205 - ............

S03 . ....... ......

COs...... ........

IT.

59.78

16.86

3.08

3.72

.14

2.96

.69

5.01

c qq

1.58

.75

99.96

V.

65.94

12.95

qq

.07

Tra PA

.10

Trace.

.05

2.32

1 1Q

4.47

12.47

99.89

"W.

69.67

13.72

.07

T^Tn f*A

2.44

.34

4.73

9 97

100. 24

X.

76.22

.11

19.45

rPvo PA

rPf»0 f*{\

rPf**J f»fi

3.82

.13

.29

100. 02
170 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

The following analyses, all by L. G. Eakins, do not appear in the 

published memoir just cited. A and B w~ere made in the Denver laboratory. The petrographic details have been supplied by Whitman 

Cross.

A. Spherulite in rhyolite, ridge west of Mount Tyndall. Mainly 

composed of quartz and feldspar needles, with some ferritic coloring 

due to decomposition of trichites.

B. Ehyolitic residual glass, same locality as A.

C. Interspherulitic mass, Rosita. Eecord No. 1285.

D. Spherulite, Eosita. Eecord No. 1286.

E, F, G. Spherulites, Silver Cliff. Eecord Nos. 1285, 1286.

These Spherulites, C, D, E, F, G, are made up of orthoclase needles, 

with free silica in fibers or grains, or rarely as tridymite.

The "soluble silica" is that which is dissolved by sodium carbonate 

solution.

SiO2 ...........

A13 03 . ..........

Fe»O3 ...........

FeO. ...........

MnO.. .........

CaO ...........

MgO. ..........

KaO. ...........

^a^O. ..........

H2O.. ..........

P

f\

Soluble SiO2 ....

A.

71.27

16.02

1.41

. .17

Trace.

35

4,08

5.76

1.14

Trace.

100.20

B.

85.50

7.42

1.23

.34

.08

.37

.82

2.64

.74

1.22

None.

100.36

C.

74.47

13.87

.51

Trace.

7.46

2.10

1.88

100.29 

12.72

D.

80.61

10.94

.26

.09

3.02

2.90

2.20

100.02 

11.12

E.

83.91

9.54

.19

Trace.

5.06

.62

.69

100.01 

1.06

F.

79.21

12.24

.43

.11

5.26

2.58

.66

100.49 

1.27

G.

78.77

12.46

.34

.09

5 84

2.12

.70

100. 32 

. 1.25
CLARKE AND") 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

4. THE BUFFALO PEAKS.

171

Hypersthene-andesite, described by Cross in Bull. 1. Contains hyperstheue, augite, plagioclase, magnetite, and apatite. Sp. gr. 2.742, 

16°. Analyses made by W. F, Hillebrand in the Denver laboratory.

A. Hyperstheue-andesite.

B, C, D. Hypersthene separated from the rock. Sp. gr. of D, 

3.307, 23°. In B and C alkalies were not tested for. In C and D all 

the iron is given as FeO.

SiOa . ............ ..

A12 03 .-.--. .......

Fe2O3 ............

FeO..............

MnO .......;.....

CaO. .............

SrO ..............

BaO. .............

MgO .............

K2 0... ...........

NasO. ............

H8 0. -...-. ........

P2 0fl .............

01. ......... ......

A.

56. 19

16.12

4.92

4.43

Trace.

7.00

Trace.

4.60

2.37

2.96

1.03

.27

.02

99.91

B.

51. 70

1.72

.30

18.00

.36

2.87

25.09

100.04

C.

51.16

2.15

18.36

.36

3.81

24.25

100. 10

D.

50.04

2.91

17.81

.12

6.70

21 74

.27

99.59
172 ANALYSES OP EOCKS AND ANALYTICAL METHODS. [BULL. 148.

5. THE LEADVILLE REGION.

Rocks described by Cross in Mon. XII, Appendix A. Analyses made 

in the Denver laboratory.

A. Porphyry, Mount Zion. Contains orthoclase, plagioclase, quartz, 

biotite, apatite, magnetite, and zircon. Analysis by L. G. Eakins.

B. White, or Leadville porphyry. Contains orthoclase, plagioclase, 

quartz, muscovite, magnetite, apatite, and zircon, with crystals which 

appear to be rutile and anatase. Sp. gr. 2.680, 16°. Analysis by 

W. F. Hillebrand. 

C. Porphyry, summit of Mount Lincoln. Contains quartz, orthoclase, plagioclase, biotite, apatite, sphene, magnetite, zircon, and allanite. The sample analyzed showed some muscovite. chlorite, and calcite. 

Sp. gr. 2,670,16°. Analysis by W. F. Hillebrand.

Si02 . .......................

Ti02 . .......................

A12 03 ... ....................

Fe2O3 .- ....... ..............

PeO. ....... .....'.. .........

MnO .......................

CaO. .......................

SrO ........................

BaO.... .....................

MgO. ......................

K20.... ....................

NasO. ......................

Li2O. .......................

H2 0.. ......................

P2 05 .... ....................

COs ...... ..................

Cl.... ......................

A.

73.50

14. 87

.95

.42

.03

2.14

.29

3.56

3.46

.90

100. 12 < 

B.

70.74

14.68

.69

.58

.06

4.12

Trace.

.03

.28

2.59

2.29

2.09

2.14

100. 29

C.

66.45

.10

15.84

2.59

1.43

.09

2.90

.07

' 1.21

2.89

3.92

.84

.36

1.35

.05

100. 09
CLABKE AND! ' 

HILLEBHAND.J IGNEOUS AND CRYSTALLINE ROCKS. 173

D. Gray porphyry, Johnson Gulch, near Leadville. Slightly altered. 

Contains orthoclase, plagioclase, biotite, and quartz, with decomposition 

products probably derived from original hornblende. Sp. gr. 2.736, 

16°. Analysis by Hillebrand.

E. Pink orthoclase'crystals from D. Analysis by Hillebrand.

F. Hornblendic porphyrite, lower Buckskin Gulch. Contains plagioclase, orthoclase, quartz, hornblende, biotite, magnetite, apatite, and 

zircon, with a little secondary calcite and chlorite. Sp. gr. 2.768, 16°. 

Analysis by Hillebraud.

G. Biotite-porphyrite, from a. dike in gneiss in the North Mosquito 

amphitheater. Composition like F, but with no hornblende, much biotite, and some pyrite. Sp. gr. 2.0740, 16°. Analysis by Hillebrand.

Si02 .... ......

TiO2 .........

AL03 - .....

Fe,03 ........

FeO. .........

MnO'.........

CaO.... ......

SrO. .........

MgO.. .......

KaO.. ........

Na,0.........

H2 0.... ......

P2 05 .........

C0a .. ........

Cl ...........

FeS*... ......

D.

68.10

.07

14.97

2.78

1.10

.09

3.04

.08

1.10

2.93

3.46

1.28

.16

.92

.03

100. li

E.

62.22

20.33

2.95

8.31

3.45

1.90

99.16

F.

56.62

16.74

4 <U

3.27

.15

7.39

4.08

1.97

3.50

.92

Trace.

1.15

100. 73

G.

-64.81

.08

15.73

1 fifc

2.91

OK

4.22

2.82

1.43

3.98

.62

.23

1.08

.04

.90

100. 61
174 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

H. Bhyolite (nevadite), from Chalk Mountain. Mainly quartz and 

feldspar, the latter being sanidine and plagioclase. A little biotite, 

magnetite, apatite, and zircon are present. Analysis by Hillebrand.

I. Sanidine from H. Analysis by Hillebrand.

Si0.2 ... ....'..-........................

AlaO.,...-... ..........................

Fe,03 .................... ......T......

FeO.... ..............................

MnO... ..............................

CaO.... ..............................

MgO.................................

K2O.... ...............................

Nas-O.. ................... ............

Li2 0 .................................

HsO... ...............................

P205 .................................

H.

74.45

14.72

.56

.28

83

.37

4.53

3.97

.66

.01

100.38

I.

65.04

20.40

70

9.74

j 4.11

.29

100. 37
CLARKE AND"! 

H1LLKBHAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

6. THE TEN MILE DISTRICT.

175

Bocks described by Cross in 14th Ann., p. 165. Analyses made in the 

Denver laboratory, A and C by W. F. Hillebrand, B by L. G. Bakins.

A. Qnartz-hornblende-mica-porphyrite, Gold Hill. Contains plagioclase, hornblende, biotite, and quartz, in a groundinass of quartz, orthoclase, and a little plagioclase.

B. Quartz-porphyrite, Sugar Loaf. Contains plagioclase, biotite, and 

quartz, in a groundmass of quartz and orthoclase.

C. Quartz-porphyrite, Chicago Mountain. Contains plagioclase, orthoclase, biotite/ and quartz.

Si02 .. ......................

Ti0.2 . ......................

A12O3 . ...... ................

Fe.203 ......................

FeO... .....................

MnO. ......................

CaO.... ....................

SrO ........................

BaO.. ......................

MgO.... ...................

KsO .....................

Na3 0. ......................

Li2O .......................

H2OatllO°. ................

H20 above 110°. ............

PB 06 . ......................

coa ........................

A.

63.66

TTndet

17. 05

1.97

2.62

.14

3.89

.08

1.99

3.09

4.13

None.

} I- 19

.27

100.08

B.

67.29

None.

15.78

1.86

1.97

.21

2.36

None.

.72

3.55

3.77

Trace.

| 2.10

.28

.27

100. 16

C.

68.30

Undet.

16.24

1.60

1.63

.12

2.79

.04

Trace.

1.05

3.52

3.90

Trace.

\ :«

.13

100. 03
176 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

The following rocks were also analyzed in the Denver laboratory, but 

the analyses are hitherto unpublished. Petrographic data furnished 

by Whitman Cross.

A. Granite-porphyry, McNulty Gulch. Contains phenocrysts of 

orthoclase, oligoclase, andesine, quartz, biotite, and altered hornblende, 

in a groundmass of quartz, orthoclase, and magnetite. Accessory 

sphene, allanite, apatite, and zircon, and a little secondary chlorite are 

also present. Analysis by W. F. Hillebrand.

B. Granite-porphyry, Jefferson Tunnel. Contains orthoclase, oligoclase, quartz, and biotite, in a groundmass of mainly quartz and' orthoclase; also accessory magnetite, apatite, zircon, and allanite. Chlorite appears as a decomposition product of biotite, and calcite and 

magnetite are present in small amounts. Analysis by Hillebrand.

C. Same as B. Analysis by L. G. Eakins. -

D. Diorite-porphyry, Copper Mountain. Contains oligoclase, hornblende, and biotite, in a groundmass of quartz, orthoclase, plagioclase, 

and magnetite; also accessory zircon, sphene, and apatite, and a little 

secondary chlorite and epidote. Analysis by Eakins.

E. Diorite-porphyry, McNulty type. Contains oligoclase, andesine, 

hornblende, biotite, and magnetite, in a groundmass of orthoclase, plagioclase. quartz, magnetite, apatite, allanite, and sphene ^also secondary chlorite, epidote, and calcite. Analysis by Eakins.

SiO*.... ........

A12 03 ... ........

Fe.2 03 .........."

FeO. ...........

MnO. ..........

CaO. ...........

SrO,. ..........

BaO...... ......

MgO ...........

K2 0. ...........

Na^O. ..........

H2O. ...........

PS 0B . ..........

C02 ... .........

01. .............

S ..............

FeS2 ...........

A.

68.60

16.21

1.67

1.57

.09

2.61

1.05

3.88

3.29

.92

.21

1Q

.03

100.32 

2. 640, 27°

B.

65.94

16.00

.60

.1.74

.14

2.87

1.02

4.56

3.85

1.13

.23

1 KK

.03

.60

100. 26 

2. 672, 21°

C.

65.51

17.01

2.79

3.16

.90

4.67

3.82

1.78

.13

Trace.

.38

100. 15 

2. 666, 26°

' D.

67.01

18.03

.66

.72

0°

Q 00

.10

.84

3.53

4.42

.91

.10

100.40

E.

63.02

17.61

1.78

2.76

3.30

i

.08

1.63

3.23

4.72

2.03

.16

100. 32 

2.689, 16°5
CtAUKE AND"! 

H1LLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

7. THE ELK MOUNTAINS.

177

Analyses made by L. G. Eakins in the Denver laboratory, and hitherto unpublished. Petrographic data supplied by Whitman Cross.

A. Bhyolite, East Mountain, Crested Butte district. Phenocrysts of 

orthoclase, oligoclase, quartz, and biotite, in a inicrospherulitic and 

cryptocrystalline groundmass.

B. Ehyolite, Bound Mountain, Crested Butte district. Small phenocrysts of quartz, sanidine, biotite, and oligoclase, in a groundmass of 

quartz and orthoclase.

C. Diorite, Brush Creek, Gunnison County. Contains several varieties of plagioclase, with orthoclase, quartz, hornblende, biotite, augite, 

sphene, apatite, and magnetite.

Si08 . .............. ...

AljOa.. ...............

Fe.2 03 ................

FeO. .................

MnO .................

CaO.. ................

MgO... ...............

K2O...... ............

NaaO. ................

H2O. .................

PsOs .................

A.

74.84

14.05

.17

.31

1.57

3.14

3.66 '

2.33

100. 07 

2. 38, 17°

B.

71.56

14.91

1.47

1.04

1.98

.08

4.94

3.78

.44

100. 20 

2.59,18"

C.

62.71

17.06

3.79

2.74

Trace.

5.51

1.78

2.96

3.54

.24

100. 33 

2. 791, 30°

Bull. 148 12
178 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

8. THE WEST ELK MOUNTAINS.

Rocks described by Cross in 14th Ann., p. 165.

A. Hornblende-mica-porphyrite, Cliff Creek. Contains plagioclase, 

hornblende, and biotite, in a grouudmass of quartz, feldspar, and mica. 

Analysis by W. F. Eillebrand, record No. 1429.

B. Porphyrite, Storm Ridge. Contains plagioclase, biotite, hypersthene, hornblende, and augite, in a groundmass of quartz and orthoclase. Analysis by L. G. Bakius, record ]So. 1238.

C. Porphyrite - diorite, Mount Marcellina. Contains plagioclase, 

hornblende, and a little biotite, in a groundmass of quartz and orthoclase. Analysis by T. M. Chatard, record No. 1238.

D. Quartz-porphyrite, Mount Carbon. Contains plagioclase. orthoel ase, biotite, hornblende, augite, and quartz. Analysis by Chatard, 

record No. 1238.

E. Quartz-porphyrite, Crested Butte. Contains plagioclase, orthoclase, hornblende, biotite, quartz, and a little augite. Analysis made 

by Eakins in the Denver laboratory.

SiOa... .........

Ti02 ...........

AlaOa. ..........

FeaOu ..........

FeO.... ........

MnO. ..........

CaO. ...........

SrO.... ........

BaO.... ........

MgO. ..........

K2 0.. ..........

Na.3 0. ..........

Li2O ...........

H2OatlOO°..... 

H2 0 above 100°. 

P2 05 ...........

COB'...... ......

A.

63.05

.60

15.58

2.92

2.11

.12

4.15

. .07

.13

1.70

3.66

3.77

.55 

1.38 

.27

100. 06

' B.

61.42

' .37

17. 69

4.24

1.74

.19

5.29

OQ

1.81

3.19

3.14

| .97 

.14

100. 28

0.

» 

62.85

.41

- 16. 21

3.08

1.46

.15

4.72

.11

1.47

3.10

3.49

.29 

2.03 

.48

99.85

D.

65.36

.52

15.48

3.09

1.21

.19

4.14

.08

1.53

3.41

3.58

.82 

.70

.25

100. 36

E.

65. 71

Undet.

18.30

1.19

1.53

.02

2.17

.98

3.95

5.00

| 1.39

100. 24
CLARKE AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

9. MISCELLANEOUS BOCKS.

179

A. Ehyolite, east bank of Arkansas Eiver, Nathrop. Described by 

Cross in Proc. Colorado Sci. Soc., vol. 2, p. 69. Contains quartz and 

sanidine in a groundmass mainly of quartz and alkali-feldspar. This 

rock carries topaz and spessartite in its lithophysae. Analysis made by 

L. Or. Eakiiis in the Denver laboratory.

B. EhyolitiC'Vitrophyre, near Del Norte, Eio Grande County. Eeported by Cross as containing phenocrysts of oligoclase, quartz, biotite, and augite in a dark, fresh, glassy grouudmass, the latter being 

predominant. Analysis made by Eakins in the Denver laboratory.

C. Ehyolite, Summit district, Eio Grande County. Description furnished by Cross. Large phenocrysts of sauidine, with smaller ones of 

oligoclase and biotite, in a groundmass of orthoclase, quartz, oligoclase, biotite, and magnetite. Analysis by Eakins, made in the Denver 

laboratory. . D. Granite, Platte Canyon. Described by E. B. Matthews for the 

Educational Series. Contains microcliue, quartz, biotite, oligoclase, 

and fluorite. Apatite, zircon, magnetite, hematite, limonite, epidote, 

and rutile (?) are sometimes present. Analysis by H. N. Stokes, 

record No. 1314.

Si02 ...........

A12 03 ..........

Fe,03 ..........

FeO.... ...:....

MnO... ........

CaO... .........

MgO. ...........

K2O.. ..........

NasO. ..........

Li2 0 ...........

H.2O.... ........

PaO«. ..........

Sp. gr. .........

A.

69.89

17.94

.39

.52

.23

.14

4.38

4.21

2.07

99.77 

2. 602, 29°

B.

68. 61

16.43

.73

1.52

1 70

.05

4.65

2.82

3.35

99.95 

2. 423, 14°

C.

68.85

17.01

1.78

.65

1.62

5.11

3.44

1.79

100. 25 

2. 489, 14°

D.

77.02

11.63

.32

1 09

1.24

.14

5.21

2.85

.35

99.85
180 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

E. Hornblende-porphyrite, Hermano Peak, Sierra El Late. Described 

by Gross in 14th Ann., p. 165. Contains plagioclase, hornblende, rare 

quartz, and a little biotite. Analysis by W. F. Hillebrand, record No. 

1429.

F. Hornblende-porphyrite, Ute Peak, Sierra El Late. Described by 

Cross in 14th Ann., p. 165. Contains plagioclase, hornblende, and very 

little augite, in <a groundmass of quartz, orthoclase, and plagioclase. 

Analysis by Hillebrand, JSTo. 1429.

G. Porphyritic augite-diorite, Lone Cone, San Miguel Mountains. 

Described by Cross in 14th Ann., p. 165. Contains plagioclase, augite, 

hornblende, and biotite, in a groundmass of quartz, orthoclase, and 

plagioclase. Inclusions of magnetite and apatite in the augite. Analysis by Hillebrand, No. 1429.

H. Augite-diorite, Sultan Mountain, San Juan County. Description 

furnished by Whitman Cross* Contains plagioclase, orthoclase, quartz, 

augite, biotite, magnetite, and apatite. Some chlorite and epidote as 

alteration products. Analysis by L. G. Eakins in the Denver laboratory. Sp. gr. 2.751,14°.

I. Augite-diorite, Stony Mountain, Ouray County. Analysis by 

Eakins in the Denver laboratory. Sp. gr. 2.891,13°.5.

SiO3 .. ..........

TiO, ...........

A13 03 ...........

Fe.,b3 ..........

FeO... .........

MnO ...........

CaO ...........

SrO ...... '......

BaO...... ......

MgO. .......- -. O

KaO. ...........

Na,0.... .......

Li3 0 ...........

H2OatlOO° ....

H2 0 above 100°. 

P2 05 ...........

GOa ...:.. ......

E.

62.65

.42

16.68

2.35

2.63'

.16

4.96

.11

.13

1.43

2.75

4.45

.27

.66 

.28

99.93

F.

59.42

.68

16.79

3.23

' 3.29

.13

5.57

.07

.14

2.24

2.82

4.15

.27

.79 

.35

. .44

100. 38

Gr.

59.19

.58

18.00

3.07

2.32

.19

6.55

.13

.18

1.41

2.74

4.01

.46

1.06 

.29

100. 18 ,

H.

63.91

17.07

4.39

1.51

4.47

.81

3.74

3.48

.33 

.21

99.92 .

I.

52.05

17.96

4. OQ

6.33

.43

8.64

5.03

1. 61 .

2.99

.97 

.31

100. 41
CI.ARKE AND"1 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 181

J. Diorite, La Plata Mountains. Data supplied by Whitman Gross. 

Contains augite, hornblende, plagioclase, and orthoclase in large 

amount, with biotite, quartz, sphene, apatite, and magnetite as subordinate constituents. Also secondary chlorite, muscovite, and calcite. 

Analysis by W. F. Hillebraud, record No. 1640. Sp. gr. 2.79, 21°.

K. Diorite-porphyry, La Plata Mountains. Data supplied by Cross. 

Contains phenocrysts of hornblende, plagioclase, occasional quartz, 

sphene, apatite, and magnetite, in a groundinass of orthoclase, plagioclase, and quartz. Also secondary epidote, chlorite, and calcite. 

Analysis by Hillebrand, record No. 1636. Sp. gr. 2.677, 24°. A trace 

of sulphur is present.

Si08 .... ..............................

Ti02 .................................

Alj03 ...... ...........................

FejOs ................................

FeO.... ..............................

(NiCo)O.... ..........................

MuO ...................'..............

CaO .................................

SrO...... ...................... ......

BaO.. ................................

MgO .................................

K20...... ............................

Na2O...... ............................

Li.,0 .................................

H2O at 110° ..........................

H20 above 110° .......................

'P,0S .................................

cos ...... ..................:.........

FeS8 .................................

3.

55.53

.95

16.80

4.06

3.35

Trace.

.16

6.96

.11

.13

3.00

3.57

4.31

Trace.

.09

.55

.47

.09

.04

100. 17

K.

60. 44

.60

16. 67

2.31

3.09

.13

4. 22

.11

.12

2.18

2.71

' 5.18

Trace.

.36

1.07

.29

.48

99.96
182 ANALYSES OF BOOKS AND ANALYTICAL METHODS. [BULL. 148.

L. Tinguaite'? From Two Buttes. Collected by G* K.Gilbert; petrographic data supplied by Whitman Cross. Consists chiefly of palegreen augite, hornblende, apatite, magnetite, and occasional crystals of 

alkali-feldspar, in an obscure, largely isotropic grouudmass. Sp. gr., 

2.79, 25°.

M. Pyroxene from L. Sp. gr., 3.43, 28°.

N. Portion of Insoluble in -fa nitric acid.

O. Syenitic lamprophyre? Two Buttes. Collected by Gilbert; 

description by Cross. Chief constituents, diopside, alkali-feldspar, 

considerable biotite, magnetite, and olivine. The ferromagnesian minerals predominate. Sp. gr., 2.88, 29°.

P. Pyroxene from O. Sp. gr., 3.45, 25°.

Q. Portion of O soluble in -fa nitric acid. .

Analyses L to Q by W. P. Hillebrand, record Eo. 1604.

Si02 ..... .......

Ti02 ...........

Zr03 . ..........

A12 03 . ..........

Cr2O3 ..........

Fe3 03 ..........

FeO. ...........

NiO. ...........

MnO. ..........

CaO ...........

SrO...... ......

BaO ...........

MgO. ..........

K,O. ...........

Na3O. ..........

Li2O ...........

H2OatllO° .... 

H2 0 above 110°.

P2 0r, ......'.....

so,, ............

s ..............

Cl .............

F ..............

L.

47.61

1.38

.18

14.26

Trace?

A Oft

4.07

.30

8.71

.36

.41 .

2.62

4.08

6.70

HPTft ftn

.26 

l.,89 

1.38 ~

1.17

.03

.37

'"P'rn f*A

100. 68

\

M.

47.54

3.00

4.14

Trace?

5.64

6.42

.36

21.57

None.

None.

10.05

.12

1.38

T^-pQ p*l

None. 

Undet.

,

100.21

]sr.

13.27

9^40

Trace.

Trace.

1.70

.11

None.

Trace.

.66

5.41

?

Uudet. 

Undet. 

1.34

.77

.03

.37

33.06

0.

50.41

1.47

None.

12.30

5.71

3.06

.04

.15

7.08

.06

.23

8.69

7.53

.97

.46 

1.80 

.46

Trace?

100. 42

P.

51.27

.70

3.05

3.08

4.34

.03

.28

22.58

None.

None.

14.21

.06

.67

None. 

Undet.

100. 27

Q.

1.58

1.00

.87

Trace.

.68

?

None.

1.22

Undet.

Uudet.

None. 

Undet. 

.46

Trace.

5.81
CI.ARKE AND"! 

HILLEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 183

UTAH.

Bocks from the Henry Mountains.

A. Porphyry. Not hitherto published. Eeported by J. S. Diller as 

containing prominent plagioclase with some augite and hornblende in 

a crystalline groundmass of quartz and orthoclase. Analysis by B. B. 

Biggs, record No. 728.

B. Augite-porphyrite dike, north spur of Mount Pennell. Contains 

hornblende, augite, and plagioclase iu a feldspathic groundmass.

0. Hornblende-porphyrite, Mount Hillers. Contains plagioclase, 

hornblende, quartz, and-onagnetite.

Analyses B and C by W. F. Hillebrand, record No. 1428. Bocks 

described by Cross in 14th Ann., p. 105.

SiOa ... ................. ...--

TiOs ...... .................

' Al,03 ... ....................

Fej03 ......:...............

FeO.... ....................

MnO ........... ............

CaO.. ......................

SrO.. ......................

BaO ........................

MgO .......................

KaO...... ...... I... ......:.

NaaO. ......................

Li20 .......................

I-IoOatlOO0 ................

HnO above 100° .............

P2 06 - .......... ...:........ ..

C08 .. ......................

SO3 ........................

A.

63.16

.21

17. 21

2.43

2.30

Trace.

6.27

Trace?

.09

1.27

1.84

4.70

.69

.12

100. 29

B.

60.98

.36

1Q OQ

1.76

1.15

.15

3.67

.28

.43

RK

3.53

6.70

.48

.44

-.10

.52

100. 29

C.

62.88

.51

17 13

1.86

2.58

.16

5.39

.12

.16

1.48

2.25

4.50

.16

.42

.26

99.86
184 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Khyolite from the Thomas Eange. Analysis made by L. G. Eakins 

in the Denver laboratory. Published by Cross in Proc. Colorado Sci. 

Soc., vol. 2, p. 69. Contains phenocrysts of quartz and sanidine in a 

groundmass mainly made up of quartz and alkali-feldspar.

Si02 ...........

AloO.3... ........

Fe2 03 ..........

FeO............

MuO ...........

CaO............

MgO...........

74.49

14.51

.57

.32

Trace.

1.03

K-0'..-... .......

Na3O... ........

Li2O ...........

HSO.... ........

4.64

3 7Q

" .64

 99.99

NEW MEXICO. 

1. BASALTS FROM RIO GRANDE CANYON.

Described by Iddings, Bull. 66; also in Amer. Journ. Sci., 3d series, 

vol. 36, p. 220. , Contain plagioclase, augite, olivine, and magnetite. 

A, B, and C contain quartz also; D is quartzless. Analyses by L. G. 

Eakins, record Nos. 847, 850.

A. Light gray, dense.

B. Greenish black, dense.

C. Dark red, vesicular.

D. Gray, dense.

SiO2 .........

Ti03 ;.....:..

A12O3 .. --....'.

Fe2 03 ........

FeO... .......

MnO .........

CaO.. ........

BaO .........

MgO.. .......

K2O. .I.......

NaaO.........

H2 0.... ......

Co2 ..........

Cl ...........

P206 .........

. A.

52.27

1 4P

17.68

2.51

5.00,

.23

8.39

.06

6.05

1.58

4.19

.82

T^Tfl f*A

100. 27

B.

52.37

1.60

17.01

1.44

5.89

.32 -

7.59

.06

6.86

1.59

3.51

1.'29

07

99.90

C.

K1 K7

1.43

17.72

6.24

1.78

.45

8. 82

.16

4.91

1.99

3.59

fid

..58

99.88

D.

52.38

1 99

18.79

2.88

4.90

.18

7.70

,11

4.91

1.76

3.99

.53

.56

99.91
CLARKE AND"! 

HILLEBBAND.J IGNEOUS AND CEYSTALLINE ROCKS. 

2. THE MOUNT TAYLOR REGION.

185

Eocks received from J. S. Diller; Analyses by T. M. Chatard, record Nos. 219, 227, 228, 235, 271, 268, and 269. Not hitherto published. 

Petrographic details furnished by Diller.

A. Lava, from canyon on east side of San Mateo Mountain.

B. Phonolitic andesite, from canyon on east side of San Mateo Mountain. Contains feldspar and corroded augite, with sometimes olivine, 

in a groundinass of feldspar and a green ferromaguesiau silicate.

C. Mica-andesite, from canyon on east side of San Mateo Mountain. 

Shows prominent plagioclase, with augite and biotite.

D. Mica-andesite, from 6 miles northeast of Grant's. Principally 

plagioclase and biotite, with less epidote, quartz, sphene, and carbonates.

E. Basalt, from 6 miles northeast of Grant's. Contains chiefly 

plagioclase, augite, and olivine, with much magnetite.

E. Augite from E.

G. Feldspar, from E. Analysis on three-fourths gram of material.

SiO,.. ........

Ti02 .........

A12 03 ... ......

Cr203 .....*...

Fe303 ........

FeO.. ........

MnO.. .......

(CoNi)O......

CaO. .........

BaO. .........

MgO.........

K3O... .......

NaaO.. .......

iW.. ........

Po06 .........

C02 . .........

A.-

68.40

17.99

2.66

1.63

.21

.67

..49

3.54

4.54

.52

100. 65

B.

65.51

.92

16.89

1.41

2.52

.31

1.19

.39

' 5.02

6.42

.16

.07

100. 81

C.

65. 78

.27

17. 32

3.68

.46

.32

1.66

.47

4.64

5.23

.14

.13

100. 10

D.

M 80

2.67

15.33

7.44

.30

7.19

6.61

4.36

2.71

1.38

.73

2.56

101. 08

E.

47.54

2.76

16.73

6.69

6.67

1Q

'8.74

.03

6.38

1.10

2.81

.36

.51

. (?)

100. 51

F.

47.06

1.82

7.77

1.30

8.15

.20

19.33

13.52

.11

.33

.20

.06

99.85

G.

52. 54

Undet.

31.26

12.34

Trace ?

.28

.42

3.55

.26

100. 65
186 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

3. MISCELLANEOUS.

A. Obsidian, from Obsidian Hill camp, Tewan Mountains. Described 

by Iddiugs, Ann. 7, p. 292. A rhyolitic obsidian, containing grains of 

iron oxide and a few microscopic feldspars. Eesembles that from 

Obsidian Cliff in the Yellowstone National Park. Analysis by L. G. 

Eakins, record No. 851. Sp. gr., 2.352, 23°.5.

B. Trachyte (?), from Los Cerillos. Described by Diller, Bull. 42, p. 

39. Analysis by F. W. Clarke, record No. 346. Eock composed chiefly 

of orthoclase, with a considerable amount of biotite, epidote, pyrite, 

and limonite, and some amorphous substance. It is the matrix or 

gangue rock of the Los Cerillos turquois.

SiO....... ............................

TiO, .................................

AlsO3 . ................................

Fe2 0s ................................

FeO. .................................

FeSi .................................

MiiO.... .............................

CaO.... ..............................

MgO .......................... J......

K2 o. ............;....................

Na,0.... .............................

^HaO... ............... ................

P2 0r, .................................

CuO.... ..............................

A.

76.20

13.17

.34

..73

.10

.42

19

4.46

4.31

qq

100. 25

B.

56.68

.22

16.62

6 OS

2.21

1.02

.59

^

'

11. 18

1 03

'-t oa

.73

100..63
CLARKE AND"! 

H1LLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

ARIZONA.

187

A, B, 0, D. Mica-basalt, Santa Maria Basin. See Iddings, Bull. Phil. 

Soc. Washington, vol. 12, p . 212. Not fully described. Analyses by 

W. F. Hillebrand, record No. 1261.

E. Hornblende-porphyrite, Sierra Carrizo. Described by Cross, 14th 

Ann., p. 165. Contains plagioclase and hornblende, in a groundmass 

of quartz and orthoclase. Analysis by Hillebrand, No. 1429.

SiO....... ......

TiO.. ...........

A1.--0,. ..........

Fe,0:i ..........

FeO.. ..........

MnO ...... .....

NiO,CoO. ......

CaO.. ..........

SrO. ...........

BaO ...........

MgO ........... O

KoO. ...........

Na2 0. ..........

LisO ...........

H2 0 at 100° .... 

H2 0 above 100°. 

PS 0B ...........

A.

49.36

.98

16.35

2.93

8.55

.19

.05

10.08

None.

, .04

7.06

.82

2.67

.22 

.65 

.30

100. 25

B.

55. 35

.87

12.91

4.67

2.06

.08

.05

5.77

Trace.

.19

6.29

4.86

2.65

Trace.

2.67 

1.18 

.58

99. 98 '

C.

57.04

.94

13. 66

4.96

1.77

.17

.07

6.23

.22

4.43

4.95

3.08

Trace?

1.11 

1.10 

.63

100. 36

D.

57.48

.94

14. 09

5.21

1.35

.09

.08

6. 05

Trace.

.23

3.49

4.69

3.00

None.

1.20 

1.37 

.65

99.92

E.

63. 18

.60

16. 47

2.36

2.28

.15

4.77

!09

.15

1.33

2.93

4.40

Trace.

.27 

.60 

.28

99.86
188 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Typical hypersthene-andesite, San Francisco Mountains. Not 

described. Analysis by T. M. Ohatard, record No. 270.

G. Becent lava, 2 miles south of Mount Trumbull. Not described. 

Analysis by L. G. Eakins, record No. 1024.

SiO, .........................

Ti0.2 .........................

Ali03 .. .......................

Fe2 03 ........................

FeO...... ....................

MnO...... ...................

CaO...... ....................

MgO .........................

K2 0... .......................

Na,0...... ...................

H2 0...... ....................

P2 06 .........................

P.

64.82

.56

18.27

3.48

.56

.20

2.89

.85

2.67

5.05

.20

.23

99. 78,

G.

45.30

2.66

14.95

1.98

9.32

Trace.

8.87

8.29

1.27

4.27

.85

2.23

99. 99

NEVADA. 

1. ROCKS FROM WASHOE.

Described by Hague and Iddings, in Bull. 17. Analyses by F. A. 

Gooch, record Nos. 119,129. FeO not separately determined. " A. Bhyolite. South-southeast of McClellan Peak. Contains feldspars, orthoclase predominating over plagioclase, quartz, mica, and 

hornblende.

B. Dacite. Spur northeast of McOlellau Peak. More plagioclase 

than orthoclase, much mica, less hornblende, little quartz.

SiO, ...... ................. ..........

AU>3 ...... ...........................

Fe3 0;i .. ..............................

CaO .................................

MgO.................................

K2 0.... ..............................

Na2O ................................

Ignition .... ..........................

A.

73.07

11. 78

2.30

2.02

.39

6.84

1.19

2.24

99.83

B.

69.96

15.79

2.50

1.73

.64

4.12

3.80

1.53

100. 07
'CLARKE AND"] 

HILLEBKANB.J IGNEOUS AND CRYSTALLINE ROCKS. 

2. ROCKS FROM EUREKA.

189

Described by Hague and Iddings, in Mon. XX.

A. Basalt, summit of Eichmond Mountain. Bed, porous. Contains 

augite, less hypersthene, feldspars, and magnetite, in ~a glassy base, 

with accessory olivine and quartz. Analysis by J. E. Whitfield, record 

No. 424.

B. Andesitic pearlite, south of Carbon Eidge. Contains plagioclase, 

hornblende, biotite, quartz, hypersthene, augite, magnetite, apatite, aud 

zircon, with a glassy base. Analysis by W. H. Melville, record No. 1240.

SiO2 .................................

TiOs.. ...............................

AlaOs- ...............................

FftjOa .........'.-....-................

FeO.. ................................

NiO.. ................................

MnO...- .............................

CaO.... ..............................

MgO. ................................

K2 0.... ..............................

NagO.... .............................

Li2O .................................

H2 0atl05° ..........................

H2 0 above 105°. ......................

P2 06 .................................

80s ..................................

A.

50.38

19.83

6.05

2.00

.38

10.03

5.36

1.76

2.15

j 1.37

.83

100. 14

B.

65.13

.58

15.73

2.24

1.86

.07

'Pro/* A

3.62

1 4.Q

3.96

2.93

.52

1 Q1

00

100". 27
190 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

CALIFORNIA. 

1. MOUNT SHASTA.

Description of rocks furnished by J. S. Diller.

A. Hornblende-andesite, Black Butte, west base of Shasta. Contains 

plagioclase and hornblende in a niicrolitic gToundmass. The latter 

carries hypersthene, magnetite, and amorphous matter. Analysis by 

W. H. Melville, record No. 1346.

B. Hypersthene-audesite, older flow, west base of Shasta. Contains 

plagioclase, hypersthene, magnetite, and glass. Analysis by Melville, 

No. 1346.

C. Hyperstheue-andesite, like B, same locality, later flow. Analysis 

by Melville, No. 1346.

D. Hornblende-audesite, late flow, eastern side of Shasta. ' Contains 

small crystals of plagioclase and hornblende in a dark groundmass. 

Thin section not examined. Analysis by H. N. Stokes, record No. 1532.

E. Ophitic basalt from near the McCloud River, south of Mount 

Shasta. A gray cellular rock. Thin section not examined. Analysis 

by Stokes, No. 1532.

F. Andesite basalt, Delta, Shasta County. Much plagioclase and a 

few hypersthene crystals in a groundmass chiefly of feldspar, pyroxene, 

magnetite, and a trace of olivine. Analysis by Melville, No. 1346.

Si02 ...........

Ti0.2 ...........

A1203 . ..........

Fe3 03 ..........

FeO ...........

MnO. ...... ....

CaO ...........

SrO... .........

BaO .......... .

MgO ...........

K,0. ...........

Na2 0. ..........

Li20 ...........

H2 0 at 110° . . . . 

H2 0 above 110°. 

P3 05 . ..........

A.

64.48

Unclet.

19.28

1.40

1.78

5.06

1.64

1.12

4.41

1 .06

99.23

B. '

64.52

Unclet.

18.31

.90

2.51

5.11

2.35

1.25

4.64

| .20

99.79

C.

' 63. 03

Unclet.

17.72

2.27

1.92

5.97

3.63

1.06

3.92

| .44

99.96

D.

61.58

.49

16.96

1.75

2.85

6.28

.03

3.67

1.28

3.94

" .24 

1.06 

.22

100. 35

E.

47.94

.57

18.90

2.21

8.59

9.86

8.21

.29

2.81

.39 

.74 

.15

100. 66

F.

55.08

Trace.

18.93

2.02

5.56

8.40

5.17

.74

4.23

| .29

100. 42
CLARKE AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 191

The following rocks are from Shasta County, but not within either 

the Mount Shasta or the Lassen Peak areas. Collected by J. S. Diller, 

who furnishes the petrographic data.

A. Dacite-porphyry, east fork of Clear Creek, 9 miles above French 

Gulch. Contains conspicuous phenocrysts of plagioclase, a few of 

quartz, and smaller ones of biotite and pyroxene, in a groundmass of 

quartz and feldspar. Analysis by J. E. Whifcfield, record No. 970.

B. Dacite porphyry, Smiths Gulch, G miles up Clear Creek from 

French Gulch. Contains phenocrysts of plagioclase, quartz, biotite, 

and hornblende, in a groundmass chiefly of quartz and feldspar. Analysis by Whitfield, No. 971.

0. Diorite, from Ono. Not described. Analysis by T. M. Chatard, 

record No. 1107.

SiOa.... ....................

TiOB .......................

Alo03 ....... ................

Fe2 03 ......................

FV>O

MnO... ....................

CaO.'... ....................

BcaO .......................

MgO. ......................

K,O.. .:....:...............

JSatO. ................... ;..

H2 0.... ....................

P,,0S .......................

S03 ~.. ....................

n

A.

66. 30

Trace.

17.55

2 19

' .55

3.12

.97

2.45

5.15

1.25

.15

.28

99. 96

B.

64. 24

.76

18.67

1. 40

1.96

4,11

1.48

1.71

4. 14

1.18

.08

22

.25

100. 20 

.05

100. 15

C.

68.10

.35

15.18'

1. 34

1.70

.20

4.66

.06

2.06

1.48

3.71

.18

99. 57

2. THE LASSEN PEAK REGION..

Kocks collected by J. S. Diller, who has furnished the petrographic 

data. Nearly all are from the area covered by the Lassen Peak map 

sheet of the U. S. Geological Survey. The quartz basalts have been 

described by Diller in Bull. 79, and partly in Amer. Journ. Sci., 3d 

series, vol. 33, p. 49. The analyses are so numerous that it seems best 

to divide them into subordinate groups.
192 ANALYSES OF ROCKS AND ANALYTICAL METHODS.

1st. KHYOLITES.

A. Ehyolite, a short distance northwest of Willow Lake, near the 

Geyser, Pluinas County. A light-gray rock with occasional phenocrysts of quartz and feldspar in a granular groundmass of the same 

materials. Analysis by W. F. Hillebrand, record No. 414.

B. Ehyolite, 2 miles northwest of Deer Creek Meadows, Tehama 

County. Shows many small crystals of quartz, feldspar, and biotite in 

a spherulitic groundmass. Analysis by Hillebrand, No. 415.

C. Ehyolite, Slate Creek, west of Deer Creek Meadows. Composed 

wholly of spherulites, some of which include crystals of feldspar or biotite. Analysis by Hillebrand, No. 416.

D. Ehyolite, summit of Mt. Stover, Plumas County. Composed 

almost wholly of spherulites, with a few crystals of feldspar and hornblende. Analysis by Hillebrand, No. 417.

B. Ehyolite, from nea^ Slate Creek, west of Deer Creek Meadows. 

A pearlite, composed chiefly of little glass balls, with a few spherulites, 

and crystals of feldspar and biotite. Analysis by Hillebrand, No. 418.

F. Ehyolite, 1£ miles northeast of Clipper Mills, on tramway to Eock 

Creek, Shasta County. A spherulitic rock containing a few microscopic particles of feldspar aud hornblende. Analysis by Hillebrand, 

No. 678.

G. Ehyolite-tuff, from the divide between the west fork of Willard's 

Creek and the stage road, in Lassen County. Elevation, 5,800 feet. 

Composed almost wholly of fine angular particles of clear glass. 

Analysis by George Steiger, record No. 1427.

Materials for A to F dried at 110° previous to analysis.

,

Si02 ............

Ti02 ............

A12O3 .... ........

Fe2 03 ...........

FeO...... .......

Mn'O. ...........

CaO.... .........

SrO. ............

BaO.. ...........

MgO ............

KsO. ............

NazO.... ........

Li,0 ............

HoOatlOO0 .....

H2 0 above 100°.. 

P2O5 ............

S03 .............

A.

74.24

,20

14.50

1.27

.67

.06

.11

.18

. .25

3.66

3.00

2.04 

.07

.03

100. 28

B.

74.65

.21

14.11

1.08

.29

.11

.80

.08

.20

4.59

2.81

' 1.40

100. 33

C.. .

73.62

.21

14.24

.93

.67

.08

1.07

.io

 .33

4.28

3.25

1.29 

.02

100. 09

D.

72.40

.18

14.81

.81

.88

.07

1.94

.04

.10

.47

3.90

3.91

.59 

.03

100. 13

"E."

73.64

.11

13.44

.60

.74

.06

1.26

.02

.11

.26

4.50

3.51

Trace.

1.99 

.06

100. 30

F.

74.60

.16

13. 41

1.28

.30

.06

1.08

.11

.26

4.50

3.38

Trace.

.85 

.03

100. 02

G.

70.01

12.61

1.47

.50

1 OR

.72

5.12

1.94

2.37

4.68 

.04

100. 52
CLABKE AND"] 

HILLEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 193

2ND. DACITKS AND ANDE8ITKS.

A. Gray dacite, Lassen Peak. Contains hornblende, biotite, plagioclase, quartz, scarce pyroxene, magnetite, apatite, and a glassy base. 

Analysis by T. M. Chatard, record No. 111.

- B. Secretion in dacite, Lassen Peak. Composed chiefly of plagioclase 

and hornblende. Analysis by Chatard, No. 110.

C. Beddish dacite, Lassen Peak. Essentially like A. Analysis by 

Chatard, No. 110.

D. Dacite from near the timber line, west base of Lassen Peak. Small 

phenocrysts of plagioclase and hornblende, with, a few of quartz, in a 

reddish-gray groundmass containing much amorphous matter. Analysis by W. F. Hillebrand, record No. 668.

E. Secretion in D. Composed essentially of plagioclase and hornblende. Analysis by Hillebrand, No. 669.

SiO2 ...........

TiOa ...........

A1303 . ...... ....

FeaOs ..........

FeO.. ..........

MnO ...........

CaO ...........

SrO.. ..........

BaO ...........

MgO ...........

KaO... .........

NaaO ...........

Li2 0 ...........

HsO.. ..........

P2 05 ...........

A.

69.51

15.75

3.34

1.71

2.09

3.34

3.89

.56

100. 19

B.

58.97

18.60

5 94

2.84

6.89

2.24

3.05

1 OK

Undet.

99.88

C.

68.20

16.98

3

7c

4.33

2.07

1 f»9

2.98

.44

100. 27

D.

co qo

01

15.26

I

CC

1.26

04

q oc .

.07

1.32-

2

Q-I

4.27

1 07

.12

100. 07

E.

55.14

.52

19.10

6.16

54

.11

8

OC

.07

rPT*n PA

4.23

1.04

q 71

TVano

93

1 Q

100. 07

Bull. 148 13
194 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Dacite, east end of Chaos, northwest base of Lassen Peak. The 

youngest dacite of the region. Contains quartz, feldspar, biotite, and 

hornblende, embedded in a clear pumiceous glass. Analysis by W. F. 

Hillebrand, record No. 670.

Gr. Secretion in F. Consists chiefly of plagioclase and hornblende, 

with some olivine and clear glass. Analysis by Hillebrand, No. 671.

H. Dacite (?), west side of old crater rim near the Thumb, at the 

head of Mill Creek, Shasta County. Shows phenocrysts of hornblende, 

plagioclase, and pyroxene, and apparently of quartz, in a gray, microlitic grouudmass. Analysis by Hillebrand, No. 674.

I. Streaked dacite, Falls of South Fork of Bear Creek, Shasta 

County. Contains plagioclase with a little sanidine, hornblende, quartz, 

magnetite, some pyroxene inclusions, and glass base. Analysis by 

E. B. Eiggs, record No. 524.

J. Dacite-tuff, Eice's Quarry, 6 miles southeast of Paskenta, Tehama 

County. Clear glass, with fragments of quartz, feldspar, and hornblende. Analysis by George Steiger, record No. 1427.

Si02 .... ........

TiOB ...........

AlsOs... ........

Fe2 03 .'.........

FeO.... ........

MnO...........

CaO. ...........

SrO. ...........

BaO ...........

MgO ...........

KnO. ...........

Na,O. ..........

Li20 ...........

H3OatlOO°.....

H3O above 100°. 

P206 ...........

. F.

68.72

Q1

15.15

1.16

1.76

.11

3.30

.03

.07

1.28

2.78

4.26

.74 

.09

99.76

G.

53.35

.56

19.22

3.28

4.48

.15

9.76

.03

Trace ?

4.86

.99

2.89

.77 

.10

100. 44

H.

63.81

.38

17.07

2.11

2.15

.09

4.97

.03

.04

 2.28

1.96

4.08

Trace.

1.03 

.10

100. 10

I.

68.10

.15

15. 50

3.20

3.02

Trace.

.06

.10

3.13

4.20

None.

2.72 

.03

100. 21

J.

65.78

14.87

1.27

1.00

Trace.

2.41

1 80

2.71

2.58

2.87

4.32 

.08

99.78
CLARICE AND"! 

HILLED RAND. J

IGNEOUS AND CRYSTALLINE ROCKS. 195

K. Pyroxene-andesite, west end of Butte Mountain, Plumas County. 

Prominent phenocrysts of pyroxene and minute ones of plagioclase, in 

a dark groundmass containing much globulitic matter. Analysis by 

W. F. Hillebrand, record No. 411.

L. Pyroxene-andesite,' south base of Burney Butte, Shasta County. 

Numerous small phenocrysts of plagioclase and a few of pyroxene, in a 

gray groundmass containing much amorphous matter. Analysis by 

E. B. Eiggs, record No. 684.

M. Hornblende-andesite, Tuscan Buttes, 7 miles east of Eed Bluff. 

A few small phenocrysts or fragments of hornblende, in a groundmass 

consisting mainly of plagioclase and gray inicrolitic matter. Analysis 

by Hillebrand, No. 412.

N. Hornblende-andesite, near Buntingville, Lassen County. A few 

phenocrysts of hornblende, in a groundmass consisting mainly of small 

feldspars. Analysis by T. M. Chatard, record No. 413.

O. Hornblende-andesite, northwest summit, head of Burney Creek, 

Shasta County. Inconspicuous plagioclase and rarely olivine, in a 

groundmass of plagioclase and pyroxene. Numerous dark spots are 

due to altered hornblende. Analysis by Eiggs, No. 683.

Eocks in this group dried at 105° before analysis.

Si02 ...........

Ti02 ...........

A1263 ........ ..

Fe,O3 ..........

FeO.... ........

MnO.... .......

CaO ...........

SrO ............

BaO ...........

MgO ...........

K20. ...........

Na2O.... .......

Li2O ...........

H2O. ...........

P2O5 ...........

S03 ............

K.

55.53

.56

17.63

2.81

3.59

08

8.74

.06

.02

5.85

.92

3.09

1 9d

.21

*

100. 33

L.

62. 44

.31

16.39

4.66

1.00

6.22

Trace.

.03

2.65

2.25

3.16

Trace.

1.02

.05

Trace.

100. 18

M.

60.93

.61

18.56

2.68

2.19

.10

6.63

.12

.02

2.37

1.33

3.79

.90

.18

100. 41

N.

67.89

.21

17.29

2.39

.21

.12

3.01

.04

.03

.66

1.69

5.11

1 34

.12

100. 11

0.

60.04

4.Q

. 17.43

5.39

.53

.08

- 6.65

?

.04

3.51

1.24

4.15

on

.04

Trace.

100. 49
196 ANALYSES OF ROCKS AND ANALYTICAL METHODS. ,[B0LL.U8.

P. Hypersthene-andesite, 1 mile west of summit on Bidwell's Eoad, 

Butte County. Eich in small phenocrysts of plagioclase and pyroxene, 

mostly hypersthene, in a groutfdmass of the same minerals, with magnetite, and probably some amorphous matter. Analysis by W. F. Hillebrand, record No. 410.

Q. Hypersthene-andesite-, old crater at head of Mill Creek. Contains 

small phenocrysts of plagioclase and hypersthene, in a groundmass of 

plagioclase, pyroxene, magnetite, etc. Some greenish pseudornorphs 

suggest former olivine. Analysis by T. M. Chatard, record No. 409,

E. Hypersthene-andesite, 2 miles south of Suppan's Mountain, 

Teh ama. County. Abundant plagioclase and hypersthene, with traces 

of hornblende, in a microlitic groundmass. Analysis by Hillebrand, 

No. 672.

S. Secretion in E. Composed chiefly of plagioclase and hypersthene, 

with some quartz and amorphous matter.. Analysis by Hillebrand, 

No. 673.

T. Hypersthene-andesite, west base of Suppan's Mountain, near Lassen Peak, Tehama County. Contains numerous microscopic crystals of 

plagioclase and hypersthene, in a microlitic groundmass. Analysis by 

Hillebrand, No. 676.

Eocks dried at 100° to 110° before analysis.

SiO2 ...........

Ti02 ...........

AlaO3 .. - ....-

Fe2O3 ..........

FeO. ...........

MnO... ........

CaO. ...........

SrO. ...........

BaO ...........

MgO ........... O

'' K2 0. ...........

Na20. ..........

Li2O ...........

H3O... .........

P205 ...........

P.

55.20

.92

18.68

3.14

4.42

.14

8.02 -

.02

.03

4.59

1.01

3.66

.51

..24

100. 58

Q.

57.11

.95

17.78

3.54

2.74

.33

.7.21

Trace?

.03

3.41

1.86

~3.81

.98

.26

100. 01

R.

63.47

.37

16.75

2.15

2.75

.09

5.72

.04

.04

3.04

1.62

3.94

.55

.13

100. 66

s.

77 04.

.47

19.11

4. 37

2.48

.12

7.34

.02

Trace?

3.94

1.16

3. 48

1.09

.08

100. 70

T.

58.08

.44

18.37

2.92

3.38

.13

7.05

.02

.03

3.35

1.33

3.66

1.09

.16

100. 01
CLABKE AND"! 

HLLLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 197

TJ. Hypersthene-andesite, 1 mile southwest of Thumb, head of 

Bailey Creek, near Lassen Peak. Abundant but inconspicuous plagioclase and hypersthene, in a microlitic groundmass containing many 

small crystals of plagioclase. Analysis by W. F. Hillebrand, record 

No. 675.

V. Hyper sthene-andesite, west summit of Crater Peak, Shasta 

County. Microphenocrysts of feldspar and hypersfcheue in a groundmass consisting largely of the same minerals, with some amorphous 

matter. Analysis by Hillebrand, 'No. 679.

W. Hypersthene-andesite, north slope of Crater Peak. Phenocrysts 

of plagioclase and hypersthene in a groundmass containing much dark 

amorphous matter. Analysis by Hillebrand, No. 680.

X. Secretion in W. Composed chiefly of plagioclase, hypersthene, 

and a globulitic base. Analysis by Hillebrand, No. 681.

Y. Andesitic tuff, Stillwater Creek, 8 miles northeast of Redding. 

Contains plagioclase, hornblende, rare hypersthene, magnetite, and 

glass. Fragments of andesite are inclosed. Analysis by W. H. Melville, record No. 1346.

Eocks dried at 100° to 110° before analysis.

SiO3 ...........

Ti02 ...........

A1203 . ..........

Cr203 ..........

Fe.2O3 ..........

FeO...... ......

MnO. ..........

CaO ...........

SrO ............

BaO ...........

MgO. ..........

K2O.. ..........

Na2 0.... .......

Li2 0 .... .......

HzO. ...........

P806 ...........

IT.

59.84

.57

16.81

Trace?

1.88

3.60

.14

6.30

.02

.07

3.85

2.13

3.63

1.04

.19

100.07

V.

68.12

.25

16.24

1.26

2.08

.10

3.80

.02

.09

1.35

2.54

3.89

.40

.14

100. 28

W.

61.17

.45

17.74

1.78

3.51

.12

5.90

.04

.06

2.76

1.71

3.79

Trace.

.83

.14

100. 00

X.

53.85

.50

18.53

T^Tn^A

1 PR

5.30

.12

9.66

.04

.03

5.88

.74

. 2.98

.45

.05

100. 09

T.

69.51

15.61

.56

1.27

2.80

.61

2.81

3.43

3.63^

100. 23
198 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. Id..;

3RD. BASALTS.

The quartz-basalts are described by Diller in Bull. 79. That from 

Mitylene was analyzed for comparison with the Cinder Cone series.

A. Quartz-basalt, from Cinder Cone, 10 miles northeast of Lassen 

Peak. Contains plagioclase, pyroxene (mostly hypersthene), olivine, 

quartz, and much unindividualized base; the latter about 25 per cent. 

Magnetite is also present; augite occurs sparingly. Analysis by W. F. 

Hillebrand, record No. 407.

B. Volcanic bomb from quartz-basalt of Cinder Cone. Analysis by 

Hillebrand, No. 665.

C. Lapilli from quartz-basalt of Cinder Cone. Analysis by Hillebrand, No. 667.

D. Volcanic sand, one-half mile northeast of Cinder Cone. Analysis 

by Hillebraud, No. 663,

E. White pumiceous inclosure from quartz-basalt of Cinder Cone. 

Analysis by Hillebrand, No. 664. Mainly glass.

Eocks dried at 100° to 110° before analysis.

SiO2 . ............

Ti02 .. .........

A1203 ..........

Cr.2 03 ..........

Fe203 ..........

FeO..:... ......

MnO ............

CaO ...........

SrO ............

BaO ...........

MgO ...........

K2 0. ...........

Na2O... .........

Li2 0 ............

H2O.. ..........

P206 ...........

A.

57.25

.60

16.45

1.67

4.72

.10

7.65

.03

6.74

1.57

3.00

.40

.20

100.38

B.

56.70

.65

15.75

1.29

5.32

.19

7.67

Trace.

.03

7.16

1.56

3.36

Trace.

.30

.20

100. 18

c.

56.53

.54

17.50

1.35

5.03

.12

8.07

Trace?

Trace.

5.94

1.55

3.51

Trace.

.27

.15

100.56

D.

55.93 

Undet.

17.34

1.50

5.20

Undet.

8 (U

?

?

7.29

1.35

3.32 '?

.26

Undet.

100. 23

E.

79.49

Undet.

11.60

.33

.49

None.

1 RA

?

? .

09

1.52

4.04

f

68

Undet.

99.88
CLARKE AND") 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 199

F. Quartz-basalt, one-half mile south of Cinder Cone, on border of 

lava field. Analysis by Hillebrand, No. 666.

G. Quartz-basalt, west end of Lake Bidwell, on border of Cinder 

Cone lava field. Contains a few grains of quartz, much olivine and 

plagioclase, less pyroxene, and a globulitic base. Analysis by Hillebrand, No. 661.

H. Quartz-basalt, Silver Lake, near Lassen Peak. Contains occasional grains of quartz, much feldspar and olivine, less pyroxene, and 

a brownish base. Analysis by Hillebrand, No. 662.

I. Quartz-basalt, resting on dacite, near west base of Lassen Peak. 

Analysis by Hillebrand, No. 677.

J. Quartz-basalt from the island of Mitylene, coast of Asia Minor. 

Analysis for comparison with the Cinder Cone series, by T. M. Chatard, 

record No. 845.

Eocks F to I dried at 100° to 110° before analysis.

SiOs ...........

Ti02 ...........

Ala03 .~. .......

Cr20;! ..........

Fea03 ..........

FeO...... ......

MnO ............

CaO. ...........

SrO. ...........

BaO ...........

MgO ...........

KaO... .........

NajO. ..........

Li2 0 ...........

H20atl05°...-.

H20 above 105°. 

P205 ...........

COa.. ..........

F.

54.56

.53

16.04

Trace.

.95

6.07

.17

8.89

.03

8.71

1.18

3.05

.28 

.18

100.64

G.

56.18

Undet.

16.59

1.51

5.51

Uudet.

7.64

?

?

7.26

1.47

3.58

?

.42 

Undet.

100. 16

H.

57.59

Undet.

16.49

1.22

4.89

Undet.

7.40

?

?

7.72

.99

3.62

?

.86 

Undet.

100. 78

I.

56.51

.48

18.10

4.26

2.68

.11

8.15

.04

.04

4.52

1.15

3.23

.69 

.14

100. 10

J.

56.58

.77

14.88

Trace?

2.31

3.04

.16

8.69

.07

3.76

2.18

- 3.36

.69

1.43

.15

2.32

100. 39
200 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

K. Eecent basalt, Pit Eiver. Rich in feldspar and augite; poor in 

olivine. Partial analysis by F. W. Clarke, record No. 109.

L. Basalt, 1 mile southeast of Paine's Creek, on the road from Eed 

Bluff to Lassen Peak. A normal basalt, rather rich in olivine. Analysis by T. M. Chatard, record No. 405.

M. Basalt, summit of Inskip Crater j 25 miles east of Eed Bluff. 

Mainly feldspar and augite, with a few phenocrysts of olivine. Analysis by Hillebrand and Chatard, record No. 406.

N. Basalt from the cone at south base of Burney Butte, Shasta 

County. Composed of plagioclase and augite, with some olivine and a 

globulitic base. Analysis by E. B. Eiggs, record No. 685.

O. Basalt, near eastern end of rim of Crater Peak, Shasta County. 

Contains plagioclase and pyroxene, some of the latter being hypersthene with a trace of olivine. Analysis by E. B. Eiggs, record No. 682.

P. Hornblende-basalt, Kosk Creek, near its mouth, by the great bend 

of Pit Eiver, Shasta County. Contains abundant phenocrysts of hornblende, with a few of plagioclase, pyroxene and olivine, in a groundmass of plagioclase, augite, and magnetite. The hornblendes are 

deeply corroded, and some have disappeared, leaving groups of magnetite grains to mark their former presence. Analysis by L. G. Eakins, 

record No. 1022. Described by Diller in Arner. Geologist, vol. 19, p. 

253.

Eocks dried at 105° to 110° before analysis, except in the case of the 

rock marked L.

SiOa --.......

Ti02 .........

AlaOa. ........

 FeA ........

FeO.. ........

MnO .........

CaO .........

SrO... .......

BaO .........

MgO. ........

K2 0.... ......

NajO. ........

Li.2O .........

HsO. .........

pao6 . ...... ..

 COa.. ........

SO3 ..........

K.

51.92

19.76

1 . 11. 21

9.30

3.38

.60'

2.16

1.54

99.87

L.

47.93

.73

18.51

2.07

7.25

.20

11.14

9.03

.24

2.28

.76

.11

100. 25

M.

50.89

.79

16.76

3.86

4.69

. 13

11. 72

Trace.

8.49

.32

2.61

' .41

OQ

100. 76

N.

52.63

.07

17.62

6.49

3,10

8.62

Trfl>C6

.04

5.64

1.73

3.38

79

.47

100.58

0.

52. 95

.66

18. 25

4.36

4.19

.12

8.73

Trace.

.01

4.93

.77

3.57

?

1.47

Trace.

T^Tfl Pft

100. 01

p.

44.77

.53

17.82

5.05

6.95

10.36

8.22

.92

2.13

2.64

.72

100. 11
OI.ARKE AND"! 

HILLEBKAND.J IGNEOUS AND CRYSTALLINE ROCKS. 201.

3. PLUMAS COUNTY.

Other rocks from this county are described nnder the heading of the 

Lassen Peak area. The following rocks, with two exceptions, were 

collected by H. W. Turner, who supplies the descriptions:

A. Granite, dike in serpentine, south slope of Grizzly Hill. Described by Turner in Amer. Geologist, vol. 17, p. 375. Contains quartz? 

albite, and inuscovite. Analysis by H. N. Stokes, record No; 1562.

B. Quartz-porphyry, near Tower Rock, Grizzly Mountains. Described by Turner in 14th Ann., p. 441. Contains porphyritic quartz, 

feldspar, and pyrite, in a fine groundmass. Analysis by W. F. Hillebrand, record No. 1273.

C. Quartz-porphyry, near Greenville. Collected by Diller, who finds 

phenocrysts of quartz in a gronndmass chiefly of quartz and feldspar. 

Analysis by Hillebrand, record No. 1458.

D. Granodiorite, southwest base of Mount Ingalls. Description supplied by Turner. Contains plagioclase, quartz, orthoclase, brown mica,

green hornblende, iron oxide, and a little apatite, sphene, and epidote. 

Analysis by Hillebrand, record No. 1456.

E. Granodiorite, Spanish Peak. Description supplied by Turner. 

Contains plagioclase, quartz, orthoclase, biotite, hornblende, iron ore, 

and apatite; also abundant secondary epidote and chlorite. Analysis 

by Stokes, record No. 1562.

Si02 ...........

Ti02 ...........

Al,03 ...... ....

FesOs. .........

FeO...... .....

MnO. ..........

CaO. ...... ....

SrO. ...........

BaO..... ......

MgO. ..........

 KaO.. ..........

Na3 0. ..........

Li2 0 ...........

H2OatlOO° .... 

H2 0 above 100°. 

P2 0fi . ..........

COs.. ':..... ....

so3 .~ .........

Cl .............

F ..............

FeS-2 ...........

A.

76.00

.04

14.88

.65

.10

Trace.

.19

 Trace.

.06

2.77

' 3. 52

.20 

1.42 

.11

99.94

B.

73.25

13.25

1.74

2.23

Trace?

.28

3.79

2.69

.07 

1.03

1 OK

.58

99.96

C.

72.77

.22

13.00.

1.28

2.65

.08

. 2.47

.67

.34

' 4.95

 .07 

1.16 

.04

.47

100. 17

D.

.67.33..

. .. ...36

15. 93

1.90.

. . 1. 59

. .09

4.09

Trace.

.... .08,.

1.63

2.46

3.76

Trace.

.19 

.66 

.11

'

100. 18

E.

59. 68

.65

17.09

2.85

2.75

6.62

.04

3.54

1.31

3.87

Trace.

.15 

1.00 

.25

.20

.03

100. 03
202 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BVLL.US.

F. Ehyolite, 3£ miles southwest of Grizzly Peak. Description furnished by Turner. Contains sanidine, witb less quartz and biotite, in 

a glassy groundmass. Analysis by Hillebrand, record No. 1461.

Gr. Hornblende-audesite, 4 miles from Pilot Peak. Described by 

Turner in 14th Ann., p. 441. Contains plagioclase and hornblende in 

a groundmass carrying grains of magnetite. Analysis by Hillebrand, 

record No. 1432.

H. Hornblende-pyroxene-andesite, southwest base of Mount Ingalls. 

Description supplied by Turner. Contains plagioclase, rhombic pyroxene, augite, brown hornblende, and magnetite, with much glass in the 

groundmass. Analysis by Hillebrand, No. 1456.

I. Hypersthene-andesite, Franklin Hill. Description supplied by 

Turner. Contains plagioclase, rhombic pyroxene, augite, and magnetite. Probably no glass. Analysis by Hillebraud, No. 1548.

SiOa.... ..........

Ti02 .............

AlsOa...... .......

Fe2O3 ............

PeO.... ..........

MnO .............

CaO... ...........

SrO ..............

BaO.... ..........

MgO .............

K20.... ..........

Na.2O. ............

Li2O .............

H2OatlOO° ......

H20 above 100°... 

P306 .............

F.

71.39

.17

14. 13

.63

.37

1.01

.09

.08

5.69

2.89

.42

3.32 

.03

100. 22

G.

60.20

.57

17.21

3.12

2:69

.12

6.04

.11

3.18

1.44

3.35

1.12

1. 18 

.17

100.50

H.

58.47

.51

18.80

3.34

2.64

.13

6.60

.05

.09

2.69

2.01

3.58

Trace.

.14

.92 

.22

100. 19

I.

56.88

- .45

18.25

2.35

4.45

.18

7.53

.04

.11

4.07

1.42

3.29

.24

.50 

.30

100.06
CLARKE Alibi 

H1LLEBBAND.J IGNEOUS AKD CRYSTALLINE ROCKS. 203

J. Dolerite, Mount Ingalls. Described by Turner in 14th Ann., p. 

441. Contains plagioclase, augite, hypersthene, magnetite, and a few 

olivines. Analysis by W. F. Hillebrand, record No. 1273.

K. Dolerite, Mount Ingalls. Also in 14th Ann., p. 441. Like J, but 

with scarcely any olivine. Analysis by Hillebrand, record No. 1432.

L. Basalt, 4 miles southeast of Mount Ingalls. Also in 14th 

Ann., p. 441. Contains plagioclase, olivine, augite, and magnetite. 

Analysis by Hillebrand, record No. 1273.

M. Oli vine-basalt, 1£ miles from Franklin Hill. Contains plagioclase, 

augite, partly altered olivine, magnetite, and probably some glass. 

Description supplied by Turner. Analysis by George Steiger, record 

No. 1596.

N. Serpentine, Greenville. Collected by J. S. Diller, who supplies 

the description. Besides serpentine, the rock contains some magnetite and less chromite, with remnants of the pyroxene from which 

the serpentine was in great part derived. Analysis by W. H. Melville, 

record No. 1346.

SiOa.. ..........

Ti02 ...........

A1303 . ..........

Fe2O3 ..........

FeO..-. ........

'MHO...........

CaO ...........

SrO.... ........

BaO ...........

MgO.. .........

KsO. .-i. ...... .

Na,2O.. .........

Li3 0 ...........

H2OatlOO°..... 

H20 above 100°. 

P2 0B ...........

J.

53.91

- .52

17.95

2.21

4.80

.10

10.40

.05

5.52

1 Si

2.90

.20 

.20 

.21

100. 31

K.

52.81

84

16.60

2.66

6.13

Undet.

10.14

Trace.

.03

6.12

1.05

2.79

.38 

.54 

.23

100. 32

L.

50.56

1.71

14. 71

3.54

8.90

.13

7.58

Trace?

.25

4.07

2.10

2.94

Trace?

1.06 

1.12 

1.14

99.81

M.

51.21

.31

17.59

4.71

4.42

10.36

. 7. 12

.91

2.49.

.58 

1.07 

.09

100.86

N.

39.14

2.08

4.27

2.04

Trace.

39.84

| 12.70

.11

100. 18
204: ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

4. BTJTTE COUNTY.

Rocks from this county are also to be found under the heading of the 

Lassen Peak area. The following rocks were collected by H. W. Turner, to whom the petrographic data are due. Analyses, with one 

exception, by W. F. Hillebrand, record Nos. 1432, 1456,1461, and 1548. 

Analysis F is by H. N. Stokes, record No. 1562.

A. Granodiorite, north side of south fork of Feather River, opposite 

Enterprise. Described in 14th Ann., p. 441. Contains plagioclase, 

potash-feldspar, quartz, hornblende, brown mica, and accessory minerals. The ferromagnesian minerals are largely altered to chlorite.

B. Granodiorite, 2 miles east of Bangor. Composition like A. The 

mica is largely altered to chlorite. See 14th Ann., p. 441.

C. Diorite, South Husent Creek. Description supplied by Turner. 

Contains feldspar, probably all plagioclase, brown hornblende, and a 

little chlorite.

D; Quartz-diorite, dike in Bidwell Bar quadrangle. Described in 

17th Ann., Part I, p. 521. Contains hornblende, feldspar, quartz, and a 

little secondary chlorite.

SiQa... ...........

Ti02 .............

A12 03 .. ...........

Fe2O3 ............

FeO... ............

NiO. ...... .......

MnO .............

.CaO. ...... .......

SrO ..............

BaO. .............

MgO .............

KaO.. ............

Na2O. ............

Li2O .............

H2 0 at 100° ......

.H2 0 above 100°...

PaOfi .............

A.

70.36

.20

15.47

.98

1.17

3.18

Trace.

.06

.87

1.71

4.91

Trace.

.06

1.00 . 

.11

100. 08

B.

63.43

.73

14.20

1.54

4.56

.03

5.51

Trace.

.06

. 2.35

2.19

3.49

None.

.15

1.50. 

.11

99.85

C.

57. 87

.53

16.30

1.71

3.86

.08

5.53

Trace.

.05

5.50

.75

5.01

Trace.

.26

2.40 

.27

100. 12

D.

K4. fii

.61

12.09

1.81

5.03

.05

.13

7.74

Trace.

.05

11.86

1.01 .

2.35

Trace.

.12

2.44 

.08

100. 01
CI/ARKE AND"] 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS.

E. Diabase-tuff. Described in 14th Ann., p. 441. Contains plagioclase, augite, epidote, chlorite, and secondary hornblende.

F. Uralite-diorite, 1 mile southeast of Forbestowu. Described in 

17th Ann., Part I, p. 521. Contains plagioclase, hornblende, and 

magnetite. 

GK Basalt, Oroville Table Mountain. Described in 14th Ann., p. 441. 

Contains plagioclase, olivine, augite, and magnetite.

H. Altered peridotite, 5 miles northeast of Strawberry Yalley. 

Largely serpentine, with olivine, hornblende, magnetite, and calcite or 

dolomite.

SiOs.... ..........

Ti02 .............

A12 03 .. ...........

Cr2O3 ............

Fe203 ............

FeO...... ........

MnO .............

MO..............

CaO... ...........

SrO... ...........

BaO.... ..........

MgO. ............ D

K20. .............

Na20...... .......

Li2O .............

H2OatlOO° ......

H2O above 100°... 

P2Ofl .............

C02 ..............

Cl...... ..........

F ................

S03 ..............

FeS2 .............

E.

54.66

.67

15.85

1.82

5.12

18

Trace?

8.75

T*!*!! PA

.04

5.64

.47

3.46

.25

2.48 

.15

.39

09

100. 02

F.

51.07

1.65

U Q3

6.44

5.98

.22

7 8Q

4. 84.

.16

5.04

.24

1.73 

iq

100. 38

G.

50.66

2.39

13.97

2.55

10.20

oq

8.-08-

.22-

4.45

1 Q^

3.32

.27

.43 

1.01

.02

99." 81 "

H.

44.81

1 1.88

.29

1.98

4.52

.13

.09

6.58

30.91

.15

.15

 6.88 

.02

1 -7Q

ioo. is
206 ANALYSES OF BOOKS AND ANALYTICAL METHODS. [BOLL. 148.

5. SIERKA COUNTY.

Bocks collected and described by H*. W. Turner. See paper in 17th 

Ann., Part I, p. 521. Additional details, supplied by Turner, are given 

here. Analyses A to H by W. F. Hillebrand, record Nos. 1456 and 

1548. Analysis I by H. N. Stokes, record No. 1514.

A. Granulite (aplite), Yuba Gap, road east of Sierra Buttes. Contains orthoclase, microcline, quartz, plagioclase, some shreds of green-- 

ish mica, and a little iron ore, chlorite, and apatite. .

B. Granulite (aplite), dike east of Milton. Contains orthoclase, 

quartz, plagioclase, a little microcline, brown mica, and iron ore.

C. Biotite-granite, Indian Valley. Contains plagioclase, orthoclase. 

quartz, brown mica, apatite, and iron ore.

D. Quartz-diorite-porphyry, dike in Indian Valley granite. Contains 

plagioclase, hornblende, biotite, and quartz.

E. Quartz-mica-diorite, large area east of Milton. Contains plagioclase, a tarbid feldspar which is apparently not orthoclase, quartz, 

green hornblende, brown mica, iron ore, and apatite.

SiOa ...........

TiO2 . ..........

Al20a-. .........

Fe2O3 . .........

FeO...... ......

MnO. ..........

CaO. ...........

SrO ............

BaO. ...........

MgO. ..........

K,O...... ......

NasO. ..........

LizO ...........

H20atl009.....

H20 above 100°. 

Pr\

A.

76. 03

.07

13.39

4.8

.31

1.28

04.

.05

5.18

2.98

 15 

 34 

.03

100. 33

B.

7K 07

no

13.07

.61

.39

1.49

.03

.14

.14

5.62

2.51

.14 

.24

100.44

C.

68.65

.28

16.34

.93

1.48

.08

3.07

.07

.09

1.29

1.85

4.85

Trace.

.24 

.62 

.15

99.99

D.

66.65

qq

17.61

Q3

1.67

.07

I 4.44

.12

1.26

1.70

4,59

.03 

.41 

.18

99.99

E.

57.26

.53

16.51

3.27

5.19

.18

6.69

.06

.10

3.41

2.93

2.65

.20 

.95 

.30

100. 23
CLARKE AND"] 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 207

F. Diabase-porphyry, dike east of Milton. Contains labradorite and 

other plagioclase, augite, and hornblende, the last mineral being perhaps secondary.

G-. Hypersthene-andesite, point northeast of Groodyears Bar. Contains plagioclase and rhombic pyroxene, a little augite, and scales 

which seem to represent former biotite, now replaced by magnetite.

H. Hornblende-pyroxene-andesite, dike southeast of Poker Flat. 

Contains .plagioclase, augite, hornblende, magnetite, some glass, and 

occasional quartz.

I. Quartz-bearing andesite, northwest of Dowuieville. Contains 

plagioclase, augite, enstatite, magnetite, occasional quartz, and probably glass.

Si02 .............

TiO2 .............

AlaOs- ............

Cr3O3 ............

Fe3 03 ............

TVO

NiO...... ........

MriO...... .......

CaO .............

SrO. .............

BaO .............

MgO... ..........

K2O.. ............

Na,2 0.. ...........

Li2 0 .............

H2OatlOO° ......

H3 0 above 100°... 

P2 06 .............

S03 ...... ........

F.

51. 27

.60

12.14

2.51

6.71

.04

.21

10.32

Trace?

.07

10.88

1.63

2.00

Trace.

.17

1.16 

.21

99.92

G.

66.94

.30

16.49

1.41

1.87 ->

.13

4.77

.05

.07

1.98

1.65

3.88

Trace.

.35

.22

 .12

100. 23

H.

59.34

.32

17.61

3.63

2.28

.12

6.45

.04

.11

3.50

1.94

3.40

Trace.

.64

.74 

.25

100. 37

I.

60.02

.42

16.07

 2.17

3.46

.10

7.01

.08

4.57

1.59

3.55

.24

.45 

.17

.06

99.96
208 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

6. NEVADA CITY AND GRASS VALLEY.

Bocks of a mining district in Nevada County, described by Lindgren 

in 17th Ann., Part II, p. 1.

A. Granodiorite, 1 mile southeast of Nevada City. Contains hornblende, biotite, quartz, plagioclase, orthoclase, magnetite, apatite, 

sphene, and pyrite. Analysis by W. F. Hillebrand, record No. 1478.

B. Granodiorite, Kate Hayes Hill, Grass Valley. Contains plagioclase, orthoclase, quartz, hornblende, pyrite, magnetite, apatite, sphene, 

and zircon. Analysis by Hillebrand, No. 1478.

C. Hornblende-porphyrite, Nevada City. Contains feldspar,. hornblende, quartz, epidote, sericite, and biotite. Analysis by H. N. Stokes, 

record No. 1531.

D. Quartz-porphyrite, New Ophir claim, Grass Valley. Contains 

plagioclase, quartz, uralite, epidote, and augite, and hornblende altered 

into chlorite. Analysis by Stokes, No. 1531.

E. Diabase, near Maryland mine, Grass Valley. Contains feldspar, 

augite, hornblende, ilmenite, pyrrhqtite, pyrite, and some chlorite. 

Analysis by Stokes, No. 1522.

F. Diabase, Grass Valley. Contains feldspar, pyroxene, hornblende, 

ilmenite, pyrrhotite, pyrite, and chlorite, and probably a little quartz. 

Analysis by Stokes, No. 1522.

SiO2 ...........

Ti03 ..........:

AlaOs.-. .......

Cr,03 ..........

Fe.2 0a ..........

FeO.... ........

MnO.. .........

CaO ...........

SrO...... ......

BaO ...........

MgO. ..........

K2 0.. ..........

NaaO. ..........

Li2 0 ...........

H20 at 110° ....

H2 0 above 110°. 

Pr\

SO3 . ...........

FeSi ...........

CuS (?)r. ........

A.

66.65

.38

16.15

1.52

2.36

. .10

453

Trace.

.07

1.74

2.65.

3.40

.18 

.72 

.10

.02

100. 57

B.

63. 85

.58

15.84

1.91

2.75

.07

4.76.

Trace.

.06

2.07

3.08

3.29

.28 

1.65 

.13

.04

100. 36

C.

62.09

.32

16.69

1.45

3.76

6.08

.10

1.93

1.84

3.36

.19 

1.47 

.39

110

99.77

D.

63.39 ".44

16.58

1.41 3.08~'

4.76

.11

2.15

2.79

3.47

.22 

1.87 

.14

100. 41

E.

51.01

.98

11.89

.04

1.57

6.08

Trace.

10.36

None.

8.87

.15

4.17

.24 

2.09 

.17

1.73

99.35

F.

53.19

1.34

17.12

4 35

5.16

 9.39

Trace.

3.98

.28

2.79

.17 

1.21 

.13

.94

100. 05
CLABKE AND 

fllLLtHRAND

.ND1 

<'D.J IGNEOUS AND CRYSTALLINE ROCKS. 209

GL Wall rock, Federal Loan mine. A siliceous argillite, of sedimentary origin. Contains quartz, feldspar, biotite, pyrrbotite, and a little 

calcite. Analysis by Hillebrand, No. 1478.

H. Altered wall rock, Providence mine. Derived from granodiorite. 

Analysis by Hillebrand, No. 1478.

I. Altered wall rock, Providence mine, back vein. Derived from 

grauodiorite and schist. Analysis by Hillebraiid, No. 1478.

J. Altered wall rock, North Star mine. Derived from uralite-diabase. Contains quartz, sericite, calcite, pyrite, and spheiie. Analysis 

by Hillebrand, No. 1478.

K. Altered country rock, Idaho mine. Derived from serpentine. 

Analysis by Hillebrand, No. 1478.

[

SiOa ...........

TiOa ...........

AlsOs ..........

Fe,03 ..........

FeO.... ........

MnO. ..........

NiO.. ...........

CaO ...........

SrO...^.. .......

BaO ...........

MgO... ........ O

KsO.. ..........

NasO. ..........

Li2 0 ...........

H20 at 110° ....

H2O above 110°: 

Pf\

COa.- ..........

FeSa ...........

Fe7S»-. .........

1 

G.

73.63 .

.52

10.54

| 1.87

Trace?

2.47

 .12

1 84

1.89

1.81

.11 

1.07 

.13

.62

3.16

.59

100. 37

H.

60.26

.46

15.73

1.25

2.68

.04

5.44

.07

1.82

3.71

1.92

. .33 

2.54 

.12

3.99

.08

100. 40

I.

59.76

.46

14.45

1.04

3.52

09

6.09

Trace?

.05

2.26

3.73

1.12

Trace.

.26 

2.58 

.16

4.47

.24

100. 28

J.

45.74

.36

5.29

.13

2.06

.26

23.85

.94

1.29

.11

Trace,

.22 

1.07 

.07

18.91 

.49

100.79

K.

36.19

.16

4.93

91

C Of>

19

.10

4.60

Trftco

22.94

.'06

.16

rP-pn rtf\

.18 

2.87

OT

21.82

.22

99.97

Bull. 148 14
210 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148..

L; Bleached country rock, next to vein, Osborne Hill mine. Derived 

from sandstone. Analysis by George Steiger, record No. 1541.

M. Altered wall rock, Empire mine. Derived from granodiorite. 

Analysis by Steiger, No. 1541.

N. Altered wall rock, Ebaugh tunnel. Derived from granodiorite. 

Mainly quartz and sericite, with pyrite, apatite, sphene, and carbonates. 

Analysis by Steiger, No. 1541.

O. Altered wall rock, Federal Loan mine. Derived from siliceous 

argillite. Analysis by Steiger, No. 1541.

SiO2 .............

Ti02 .............

A1203 ............

Fe2 03 ............

FeO.... ..........

MnO.... .........

CaO .............

BaO .............

MgO... .......... O

K2O. .............

Na^.... .........

H2O at 100° ......

H20 above 100°... 

P2 05 .............

 S03 ...............

CO2 .. ............

FeS2 .............

L.

71.97

.88

15.75

.77

4.^

.80

.80

4.88

.33

.30

2.16 

.15

.38

.56

100. 18

M.

58.43

17.40

.77

, 2.19

None.

5.25 '

1.50

4.03

1.76

.30.

2.61 

.13

4.04

1.59

100. 00

N.

56. 25

.25

17.65

.76

9, fid

4.46

.03

1.69

6.01

.30

.30

.2. 36 

.21

4.82

2.87

100. 60.

0.

34.91

1.65

15.55

.17

4.96

11.10

4.58

4.28

10

.30

1.86

:82

IK K7

4.20

100. 14
CLARKE ANDT 

H1LLEBBAND.J IGNEOUS AND CRYSTALLINE EOCKS. 211

7. PLACER COUNTY.

First, a series of rocks from the Ophir mining district, described by 

Lindgren in 14th Ann., p. 249. Analyses by W. F. Hillebrand, record 

Nos. 1419,1433,1434.

A. Granodiorite, from quarries at Lincoln, 8 miles west of Ophir. 

Contains feldspars, quartz, biotite, and hornblende.

JB. Pyritiferous amphibolite, Conrad tunnel. Partly altered. Contains pyrite, hornblende, magnetite, feldspars, quartz, epidote, chlorite, 

a few scales of mica, rutile, and, carbonates.

C. Dike rock, near camptonite, Casey's tunnel, Flat Ledge, Duncan Hill. Contains hornblende, feldspars, pyrite, and apatite, with 

secondary epidote and quartz.

D. Altered wall rockj Mina Eica vein.

E. Altered wall rock, Plantz vein. These rocks, D and E, contain 

quartz, muscovite, a little chlorite, pyrite, and sphene, with carbonates 

of calcium, magnesium, and iron.

Si02 :......-...

Ti02 ...........

A1203 ..........

Fe2O3 ..........

FeO. ... -....-...

MnO... ........

Ni,Zn.... ......

CaO ...........

SrO. ...........

BaO ...........

MgO.. ......... O

KaO.-.. ........

NaaO. ..........

Li2 0 ...........

. H20 at 100° .... 

H20 above 100°. 

P20fi ...........

S03 . ...........

COa.... ........

FeS2 ..'.........

Cu2S(?)........

- A.

65.54

.39

16.52

1.40

2.49

.06

4.88

Trace.

2.52

1.95

4.09

.12 

.59 

.18

100. 73

B.

45.56

1.11

14.15

1.20

9.83

.25

2.30

Trace.

Trace.

. 6.76

1.18

1.57

.23 

4.84 

.14

.03

3.04

7.86

.10

100. 15

C.

. 60.09

.63

16.43

2.28

3.01

.12

5.76

Trace.

4.37

.70

4.52

.20 

1.16 

.12

.07

3d

99.80

D.

37. 01

.85

12.99

.43

3.57

 '.24 '

Traces.

9. 78

Trace.

5.49

4. 02

.13

.13 

1. 92 

.06

.04

15.04

7 9Q

99.69

E.

46.13

.67

*15. 82

.89

2.27

.09

Traces.

10.68

Trace.

Trace.

2.13

5. 30

.17

Trace.

.12 

2.42 

.10

.04

11.24

1.61

99.68
212 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Second, rocks from other localities in Placer County. Studied also 

by Lindgren, who furnishes the petrographic data. Analysis A by W. 

H. Melville, record No. 1346; B, C, D, E, by W. F. Hillebrand, record 

No. 1419.

A. Granite from Eocklin. Collected for the Educational Series. A 

normal granite, containing quartz, orthoclase, plagioclase, biotite, muscovite, magnetite, apatite, and zircon, with some secondary chlorite and 

epidote derived from the biotite.

B. Graiiodiorite, Donner Pass. Contains plagioclase, orthoclase, 

quartz, hornblende, biotite, and spheneV

0. Gabbro,2 miles south of Emigrant Gap, on road to Onion Valley, 

Contains biotite, hypersthene, diallage, plagioclase, and orthoclase.

D. Gabbro, same locality as the last. Contains hypersthene, diallage, 

plagioclase, and orthoclase.

E. Augite-granite, southeast spur of English Mountain. Contains 

"basic" plagioclase, augite, and quartz.

SiOs- ..........

TiO2 ...........

A1203 - ..........

Fe2 03 ...I......

FeO. ...........

MnO.. .........

CaO ...........

SrO.... ........

BaO ...........

MgO ...........

K20.... ........

Na20. ..........

Li2O. ..........

H3OatlOOG .... 

H2O above 100°. 

P205 ...........

' A.

73.00

16.38

'.99

2.42

48

1.87

4.53

} .52

100. 19

B.

59.48

.93

17.25

2.15

4.06

.11

6.50

.09

2.67

2.27

3.53

.09 

.71 

.33

100. 17

C.

55.40

.60

15.32

2.70

5.49

.11

9.90

.07

5.75

1.52

' 2.89

Trace.

.03 

.38 

.22

iOG. 38

D.

55.87

.56

13.52

2.70

 5.89

.10

8.87

.02

6.51

1.72

 2.42

Trace.

.09 

1.56 

.25

100. 08

E.

64.67 i 

.51

16.62

.51

.76

9.50 '

.02

2.26

.34

4.10

Trace.

.08 

.37 

.12

99.86
CLARKE AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

8. ELDORADO COUNTY.

213

A. Granitite, Placerville Canal, one-third mile north of Ditch Camp 

No. 7. Collected by W. Lindgren, who reports it as containing biotite, 

orthoclase, plagioclase, and quartz. Analysis by George Steiger, record 

No. 1591.

B. Granodiorite, 2 miles south of Silver Lake Hotel. Collected by 

Lmdgren, who reports it as containing hornblende, biotite, plagioclase, 

and quartz. Analysis by Steiger, No. 1591. Analyses A and B are 

published by Lmdgren in Amer. Journ. Sci., 4th ser., vol. 3, p. 306.

C. Porphyrite, 1 mile southwest of Latrobe. Published by Turner 

in 17th Ann., Part I, p. 521. Contains abundant plagioclase, less 

augite, calcite or dolomite, iron disulphide, a little chlorite, and secondary greenish mica. Analysis by W. F. Hillebrand, record No. 1432.

Si02 . ....... ................

TiOa ........................

AliOs- ------- ,.-----. ......

Fe2 03 .....'.................

FeO... .....................

MnO. ................ ......

CaO. ........ ...............

SrO...... ..................

BaO... .....................

MgO .......................

K2 0.... ....................

Na»O. ...... ........ .:......

H2OatlOO° ................

H2 0 above 100°. ............

p r>

C09 .... ....................

FeS2 .......................

A.

77.68

 .14

11.81

.72

.51'

.72

.18

5.00

2.96

.04

.27

.10

100. 13

B.

67.45

.58

15.51

1.76 '

2.21

3.60

1.10

3.66

3.47

.14

.63

.12

100. 23

C.

68. 58

.57

'13. 04

.26

3.40

.15

3.22

Trace.

.10

1.01

1.90

4.94

.16

1.00

.20

1.31

.15

. 99. 99
214 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

9. AMADOR COUNTY.

Bocks collected by H. W. Turner, and analyses published in 14th 

Ann., p. 441, and 17th Ann., Part 1, p. 521. Additional data supplied 

by Turner. Analyses by W. F. Hillebrand, record Nos. 1432, 1456, and 

1597.

A. Ehyolite, south point of Buena Vista Peak. Contains sanidine, 

quartz, and biotite in a glassy groundinass.

B. Biotite-granite, north fork of Tuolumne Eiver. Contains plagioclase, microclirie, quartz, abundant biotite, iron ore, sphene, apatite, 

and perhaps rutile. 

C. Biotite-granite, north fork of the Tuoluinne Eiver. Like B.

D. Quartz-porphyrite-schist, 2£ miles southeast of Bueua Vista Peak. 

Contains porphyritic quartz and hornblende; also calcite and other 

carbonates. See 14th Ann.

E. Quartz-diorite-gneiss, north fork of Tuolumne Eiver. Contains 

plagioclase, hornblende, quartz, brown mica, accessory biotite, and iron 

oxide. ...

F. Diorite-porphyry, north fork of Tuolumne Eiver. Contains plagioclase, brown hornblende, epidote, and a little sulphide of iron and 

chlorite. ' ... ,

'.SiO, ...........

TiO.2 . ..........

A12 03 ..........

Fe3 03 ..........

FeO... .........

MO......'......

MnO.. .........

CaO ...........

SrO ............

BaO ...........

MgO ...........

KaO. ...........

Na2 0. ..........

Li2 o :.... .....

H2O at 100° .... 

H2O above 100°. 

PS06 ...........

CO2 ...... ......

FeS2 ..........

A.

73. 23

.09

12.73

.99

.16

Trace.

.61

.02

.22

5.17

1.91

Trace.

.53 

4.51 

.02

100. 19

B.

70.75

.42

15.13

OS

1.43

None.

Trace.

3.09

.04

.12

.73

3.62

3.05

.10 

.51 

.10

.06

100. 13

c.-

70.43

. 24

15.51

1.28

?

2.76

.05

.20

.37

5.14

2.75

.08 

.40 

.11

Trace.

100. 28

D.

70. 29

.29

11.83

1.30

 2. 08

.12

2.30

Trace?

.07

1.24

3.05

2 68

.10 

1.35 

.07

3.25

100. 02

E.

57.41

1 04.

17.71

2.16

K 01

.02

. .15

6.73

. .04

.09

3.38

1.82

3.12

.20 

1.14 

.24

100.-26

' F.

'55. 18

.83

17.35

2.77

3.90

.03

is

7.98

.06

04

4.80

1.42

3.42

T^vn f*f*

.16 

1.52

on

98

100. 09
CLARKE AND"! 

HILLEBBAND.J IGNEOUS AND CRYSTALLINE KOCKS. .215

G. Diorite; nortli fork of Tuolumue River. Contains quartz, feldspar, 

biotite, sphene. epidote, and secondary chlorite.

H. Diorite, north fork of Tuoluinne River. Contains plagioclase, 

quartz, hornblende, biotite, apatite, iron ore, epidote, and chlorite.

I. Plagioclase-gneiss, north fork of Tuolumne River. Contains 

plagioclase, hornblende, biotite, and apatite.

J. Plagioclase-gneiss, north fork of Tuolumne River. Contains 

plagioclase, hornblende, brown mica, apatite, epidote, and grains of 

iron ore.

K. Wollastonite-gneiss, north fork of Tuolumne River. Mainly 

wollastonite, but garnet, quartz, and sphene are also present.

L. Melaphyr-tuff, altered basalt, west of Jackson. Contains augite 

and plagioclase, with secondary quartz, chlorite, and chrysotile. 

Originally glassy in part, but devitrified. See 14th Ann.

SiO, ...........

Ti03 ...........

AliOs- ..........

Fe,0:) ..........

FeO.. ..........

MO............

MnO ...........

CaO...... ......

SrO ............

BaO. ..--...:...

MgO ...........

KaO.. ..........

Na,0 ...........

Li.,0 ...........

H,OatllO° .... 

H.2 0 above 110°. 

P,0fi ...........

CDs.... ........

Fes* ...........

G.

69. 66

.21

17.57

.21

1.04

Trace.

4.54

.05

.03

.58

.71

4.91

.05 

.50 

.03

Trace?

100. 09

H.

55. 86

1.20

19.30

.91

4.78

.16

7.31

.04

,.13

2.94

1.52

3.52

.19 

1.23 

.38

.39

99.86

I.

52.21

1.16

18. 79

2.71

5.30.

.06

-, 8.01

.08

x 5.11

1.60

3.31

.12 

1.35 

.36

.06

100. 23

J.

46. 63

1.82

19.49

3.26 '

6.63

.02 .

.21

9.15

..06

.14

5.37

1.55

3.19

.10 

1.61 

.66

.19

100. 08

K.

50.67

.20

6.37

. .31

' .50

40. 34

. .58

.22

.14

.08 

.31

.52

.100.24

L.

49.24

.96

14.79

1.36

-8.00

.18

10.74

Trace.

.04

6.89

.88

2.76

Trace.

. .20 

2.97 

.17

.90

100.08
216 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

10. CALAVERAS COUNTY.

Eocks collected by H. W. Turner, and described in 14th Ann., p. 441. 

Additional data supplied by Turner relative to analysis B. . Analyses 

by W. F. Hillebrand, record No. 1432.

A. Granitoid quartz-porphyrite, If miles southeast of Milton. Contains quartz, feldspar, and hornblende.

B. Quartz-porphyrite, 1£ miles northeast of Milton. Contains feldspar, quartz, epidote, chlorite, and iron ore, in a groundmass made up 

probably of feldspar and quartz.

C. Porphyrite, 1£ miles northward from Jenny Lind. Contains 

quartz, plagioclase, epidote, and chlorite derived from augite.

SiO2 ...... ..................

Ti02 . ......................

A12 03 . ......................

Fe2 03 ......................

FeO...... ..................

MuO. ..._ .......... .......

CaO...:.. ..................

SrO.... ....................

BaO.... ....................

MgO. ......................

K2 0...... ..................

Na20 ......................

H2Oat 100° ................

H2O above 100°. ............

P205 .......................

C0a . ..........:............

i .

A.

72.24

. .41

13.84

1.45

1.86

.12

3.40

-Trace.

.08

1.10

..39

4.43

.17

.69

.10

100. 28

B.

71.19

.35

13.81

1.45

1.68

.07

2.87

Trace.

.16

 .74

1.82

4. 24 

.15

.92

.08

' .82

100. 35

C.

61.37

.60

15. 41 -

3.15

3.89

.47

4.42

Trace.

.08

3.48

.34

3.76

.'29

2.70

.08

100. 04
CLAUKE AND"! 

H1LLKURAND.J IGNEOUS AND CRYSTALLINE ROCKS. 

11. TUOLUMNE COUNTY.

217

Eocks collected by H. W. Turner, aud partly described in his papers 

in the 14th and 17th Annuals. Additional data supplied by Turner.

A. Soda-syenite-porphyry, dike east of Moccasin Creek. Consists 

mainly of albite, with a greenish mineral which is probably aegirite. 

Analysis by H. 1ST. Stokes, record No. 1563.

B. Augite-syenite dike, Turnback Creek, about 1 mile north of Carter Post-office. Hitherto unpublished. Contains orthoclase and augite, 

with less plagioclase and quartz. Analysis by Stokes, No. 1642.

C. Trachyte-audesite-tuff, If miles southwest of Clover. Meadow. 

Described in 17th Ann., Part I, p. 521. Contains glaSvS, plagioclase, 

probably some sanidine, and biotite. Analysis by W. F. Hillebrand, 

record No. 1597.

D. Trachyte-audesite, from about 14 miles northeast of the Big Trees 

Hotel, near Clover Meadow. Hitherto unpublished. Examined petrographically by F. L. Eatisome. Contains plagioclase, in part labraclorite, augite, iron ore, some olivine, apatite, and brown glass. The 

potassium is probably in the glass, as no potash mineral was observed. 

Analysis by H. N. Stokes, record No. 1645.

Si02 .. ............

Ti02 .............

Zr02 .............

A12 03 . ............

Fe2 03 ............

FeO.. ............

MnO. ;...........

CaO...... ........

SrO ...............

BaO...... ........

MgO .............

KoO. .........'....

NasO. ............

Li2 0 .............

H2O at 110° ......

H2 0 above 110°... 

P2 05 .............

so:! ..............

F ................

Cl...... ..........

C ................

FeS3 .............

A.

67. 53

.07

18. 57

1.13

.08

.55

.24

.10

11.50

.15

.31 

.11

Trace.

100. 34

B.

61.28

.41

14.71

1.21

2.85

5.61

.04

.72

1.69

7.70

2.99

.28

.43 

.16

.08

100. 16

C.

62.33

1.05

.04

17.31

3.00

1.63

.08

3.23

.05

.24

1.05'

4.46

4.21

.44

.75 

.29

.11

.06

100. 33

D.

59.43

1.38

.08

16.68

2.54

3.48

4.09

.14

1.84

5.04

3.72

.27

.72

.58

.05

100.04
218 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

B. Diorite, dike 1£ miles southeasterly from Sonora. Contains feld 

spar largely altered to hornblende. A few black grains are probably 

iron ore. Analysis by W. F. Hillebrand, record No. 1548.

F. Quartz-pyroxeue-diorite, large area east of Sonora. Contains 

plagioclase, quartz, biotite, augite, rhombic pyroxene, and a trace of 

iron ore. Analysis by Hillebrand, No. 1548.

G. Diorite, dike about 1£ miles southeasterly from Sonora. Contains 

altered plagioclase and hornblende, with epidote, chlorite, and iron 

disulphide as secondary products. Analysis by Hillebrand, No. 1548.

H. Basalt, Table Mountain. See 14th Ann. Contains plagioclase, 

olivine, augite, and magnetite. Analysis by Hillebraud, record No. 1273.

SiOs .............

Ti02 .............

A1.2 03 ............

Fe.203 ............

FeO.... ..........

. MnO. .:..........

NiO.. .............

CaO.... ..........

SrO ......'.. .......

BaO .............

MgO... ..........

KsO. ....."........

Na2O.. ...........

Li.2 0 .............

H2 0 at 110° ......

H20 above 110°... 

P2 0fi .............

CO.2 ...... ........

FeSa .............

E.

58. 05

.72

15.46

1.69

5.09

.14

6.94

Trace.

.07

4.84

2.14

2.86

Trace.

.10

2.02 

.16

100.28

 F.

57.80

.70'

16.43

1.62

6.51

.18

.03

7.21

Trace?

.09

4.14

" 2.29

2.35

Trace.

.11

 .38 

.19

100: 03

G.

53. 46

.70

14.81

2.60

5.15

.18

.05

8.44

Trace.

.05

' 7.27

.1.30

2.64

Trace.

.12

2.13 

.16

.44'

.26

99.76

H.

56.19

.69

16.76

3.05

4.18

.10

6.53

Trace.

.19

3.79

4.46

2.53

Trace.

.34

.66

KK

100. 02
CLARKE AND~1 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE EOCKS. 

12. MARIPOSA COUNTY.

219

Eocks collected by H. W. Turner, and partly described in his papers 

in the 14th and 17th Annuals; Additional data supplied by Turner.

A. Soda-granulite or aplite, about 4 miles west of Mariposa. See 

17th Ann., Part I, p. 721. Contains plagioclase (albite *?) and micropegmatite, with less epidote, quartz, sphene, and apatite. Analyses 

by W. F. Hillebrand, record No. 1461.

B. Micropeginatite, Agua Fria Creek. See 17th Ann., Part I, p. 691. 

Contains quartz, plagioclase, brown mica, epidote, and a little iron ore. 

Analysis by Hillebrand, No. 1461.

C. Soda-granite-porphyry, Merced River, below the mouth of the 

north fork. Published in 17th Ann. Contains feldspar, largely albite, 

hornblende, inuscovite, abundant epidote, apatite, and a little iron ore. 

Analysis by George Steiger, record No. 1573.

D. Granite-porphyry, about one-fourth of a mile north of Lake Tenaya, Yosemite National Park. See 14th and 17th Anns. Contains 

orthoclase, quartz, plagioclase, and biotite, with a little iron ore and 

sphene. Analysis by Hillebrand, record No. 1432.

E. Granite, west of Lake Teuaya, Yosemite National Park. See 14th 

and 17th Anns. Contains quartz, orthoclase, plagioclase, and biotite, 

with some hornblende, iron ore, sphene, and apatite. Analysis by 

Hillebrand, No. 1432.

Si6.2 ...........

TiO, ...........

AloO:, ..........

Fe2 0r... .......

FeO.. ..........

MnO ...........

CaO ...........

SrO...... ......

BaO ...........

MgO.. .........

K2 0. ...........

Na3 0. ..........

LiaO ...........

H2OatllO° .... 

H2 0 above 110°. 

'P2 06 ...........

CO.............

A.

74.21

.30

14.47

.35

.50

None.

1.71

Trace.

None.

.28

.10

7.62

.15 

.23 

.07

99.99

B.

73.18

.25

13.66

.21

2.24

.07

2.10

.10

.93

2.72

3.70

.10 

.57 

.09

.17

' 100.09

C.

.71. 88

.17

15.57

1.07

.30

None.

2.03

.08

.02

.68

1.80

5.81

.11 

.68

.08

100. 28

D.

72.48

.28

14.06

.89

1.05

Trace.

2.17

Trace.

.08

.62

4.75

3.30

.16

' .35 

.09

100. 28

E.

66.28

.54 '

*16. 03

1.80

1.88

.05

3.75

Trace.

.08

1.12

3.49

4.10

.10 

.39 

.30

99.91
220 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Quartz-mica diorite, Chowchilla Eiver. See 17th Ann., Part I, p. 

691. Contains plagioclase, quartz, a little orthoclase (?), brown mica, 

hornblende, rather abundant apatite, a little iron ore, and one zirconlike.crystal was noted. Analysis by W. F. Hillebrand, record No. 1461.

Gr. Quartz mica-diorite, Yaqui Creek. For the Educational Series 

of Rocks. Contains plagioclase, quartz, biotite, hornblende, a little 

pyroxene, iron ore, and apatite. Analysis by George Steiger, record 

No. 1643.

H. Diabase, dike 1£ miles northeast of Hornitos. See 17th Ann., 

Part I, p. 694. Contains plagioclase, partly labradorite. augite, brown 

hornblende, and iron ore. Analysis by Hillebrand, No. 1461.

I. Igneous rock, near Cathay Hill. See 17th Ann., Part I, p. 694. 

Contains two minerals unidentified. Neither is olivine. Analysis by 

Hillebrand, No. 1461.

Si08 .............

TiO, .............

A12O.) ............

Cr203 .............

Fe2O3 ............

FeO.... ..........

NiO... ...........

MnO... ..........

CaO .I...........

SrO.. ............

BaO .\. ..........

MgO .............

K2 0 .............

Na./).... .........

Li,0 .............

H2OatllO°......

H2O above 110°... 

P2 0fi ............

CO9 .... ..........

S03 .... ..........

01.. .............

F ...:............

C ................

F.

62.62

.55

17.51

.49

4.06

.05.

5.49

Trace.

Trace.

2.84

1.76

3.49

Trace.

.22

.92 

.12

100.12

G.

58.09

.95

17.46

1.12

. 5.08

None.

6.24

.04

.07

4.06

2.02

2.94

.29

1.45 

.17

.21

.05

..02

.11

100. 37

H.

51.32

1.23

15.28

.47

8.59

.16

11.58

Trace.

None.

7.25

.22

2.92

Trace.

.06

.95

.25

100. 28

I.

 47.75

.37

10. 56

.24

.74

8.34

.07

.10

9.62

Trace.

None.

19.09

.'12

1.32

. .05

2.06 

.03

100. 46
CLARKE AND"! 

H1LLEBBAND.J IGNEOUS AND CRYSTALLINE ROCKS. 221

J. Feldspathic mica-schist, Chowchilla Eiver. See 17th Ann., Part 

I, p. 691. Contains quartz, feldspar, biotite, muscovite, apatite, and 

specular iron. Analysis by W. F. Hillebrancl, record No. 1461.

K. Andalusite-hornfels, Yaqui;Gulch. For the Educational Series of 

Kocks. Principally quartz, andalusite, brown and white mica, black 

graphite-like grains, a little iron ore, and probably feldspar. Analysis 

by George Steiger, record No. 1643.

L. Andalusite-schist, Chowchilla Eiver. See 17th Ann., Part I, p. 

691. Contains quartz, biotite, andalusite, sericite, a little muscovite, 

probably graphite, iron ore, a few garnets and apparently chlorite. 

Analysis by Hillebrand, No. 1461.

M. Chiastolite-schist, Yaqui Gulch. Contains chiastolite, sillimanite, brown mica, sericite(?), probably graphite, and clear grains which 

appear to be quartz and feldspar. Analysis by Steiger, No. 1643.

N. Hornfels, Agua Fria Creek. See 17th Ann., Part I, p. 691. Contains quartz, brown mica, iron ore and plagioclase. Analysis by 

Hillebrand, No. 1461.

SiOa ...........

Ti02 ...........

A13 03 ..........

' Fe*03 ..........

FeO ...........

MnO. ..........

CaO ...........

SrO. ...........

BaO ...........

MgO. ..........

K2 0 ...........

Na2 0. ......:...

Li2O ...........

H2OatllO° .... 

H2O above 110°. 

P2 05 ...........

SO3 ............

PI

F ..............

C ..............

T lAnn O i

J.

70.40

.51

14.70

.65

2.57

.08

1.63

Trace.

.09

1.47

3.46

3.17

Trace.

.19 

.91 

.05

.15

100. 03

K.

65.10

.72

17.77

1.95

3.29

None.

1.38

None.

None.

1.43

2.45

2.25

None.

.47 

2.49

;14

.03

.12

1.21

100. 80 

.06

100.74

L.

64.28

.65

17.28

1.10

5. .34

.09

1.19

Trace.

.10

2.57

2.93

.91

 Trace.

.20 

2.72 

.27

.43

100. 06

M.

62.15

.80

19.34

4.23

2.25

1.50

None.

.04

1.88

3.07

1.60

None.

.19 

1.79 

.15

.13

.22

1.12

100.55 

.10

100. 45

N.

68.27

.57

14, 03

.46

4.68

.04

3.89

Trace.

.08

2.23

3.35

2.29

Trace.

.08 

.98 

.21

100. 16
222 ANALYSES OF EOCKS AND ANALYTICAL METHODS. [BULL. 148.

13. THE QUICKSILVER REGION.

Bocks described by Becker in Mon. 13. Analyses made by W. H. 

Melville in the San Francisco laboratory. With one exception, the 

serpentine from New. Idria, all the rocks are from the districts north of 

San Francisco.

A. Pseudo-diabase from near Mount St. Helena. Contains augite, 

hornblende, oligoclase, albite, zoisite, ilmenite, leucoxene, and a little 

chlorite.

B. Pseudo-diabase from Sulphur Bank. Contains oligoclase, a little 

quartz, pyroxene, hornblende, ilmenite, sphene, serpentine, and chlorite.

C. Pseudo-diorite from Knoxville. Mainly actinolite, with a little 

white mica, chlorite, serpentine, sphene, rutile, and zircon.

D. Glaucophane-schist, Sulphur Bank. Mainly glaucophane and 

zoisite. Quartz, albite, muscovite, and sphene are also present.

Si02 .............

Ti02 .............

A12 03 - ............

Cr2 03 ............

Fe2O3 ............

FeO... ...........

MnO. ............

NiO. .............

CaO .............

MgO .............

K2O. .............

NagO. ............

H2OatlOO° ......

H20 above 100°... 

P306 .............

A.

49.08

1.72

14! 68

1.95

9.63

.15

10.09

6.69

.20

4.60

.27

1.18 

..23

100.47

B.

51. 28

1.33

15.05

2.42

8.01

.25

.10

7.08

6.07

.12

4.43

.39

2.96 

.13

99.62

C.

50.44

8.18

.48

1.06

6.29

.21

11,55

17.63

.50

2.98

.07

.92

100.31

D.

49.68

1.31

13.60

1.86

8.61

.04

10.97

6.26

.12

3.09

. 3.84 

.21

99.59
CLARKE AND"! 

H1LLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 223

E. Andesitic obsidian, Clear Lake. Shows grains of plagioclase, 

augite, and hypersthene. Sp. gr. 2.391.

F. Audesite (asperite). Clear Lake. Contains pyroxene, plagioclase, 

magnetite, and sometimes biotite. Pyroxene mostly rhombic. Sp. gr. 

2.664.

Gr. Obsidian, from south of Borax Lake. Sp. gr. 2.390.

H. Basalt, south of Burns Valley. Eich in oliviue, with a microlitic 

groundmass of plagioclase and augite. Sp. gr. 2.380.

I. Ordinary basalt from Knoxville.

Si02 .. .....'.....

Ti09 ...........

AleOs ..........

Cr2 03 ..........

Fe.2Q3 ..........

 FeO.. ..........

MnO. ..........

NiO.... ........

CaO ...........

MgO. ..........

K20...... ......

NasO. ..........

H20 at 100° ....

H20 above 100°. 

P205 ...........

Cl .............

E.

74.01

.24

12.95

1.42

.99

.48

4.65

5.34

.29 

.01

.07

100. 45

F.

65.43

1 .83

17.10

2.39

1.19

.70

.2

3.88

1.48

2.83

3.66

.20

.36 

Trace.

100. 25

G.

75.40

7.72

1.41

.12

1.55

1.26

4.52

8.09

} .«

.12

100. 62

H.

57.37 '

.60

15. 66'

2.06

4.46

.27

.41

4.94

8.84

1.51

3.05

.61

.12 

.02

99.92

I.

51.66

11.22

.25

1 7.62

.12

7 79

13.61

SO

5.98

} 1.06

100. 13

J. Light-green, inarmolitic serpentine, New Idria.

K. Black serpentine, Sulphur Bank.

L. Light-green serpentine, Sulphur Bank.

SiO2 .......................

A13O3 - ......................

Cr3O3 ......................

Vaf)

MnO ............ -:.3?......

NiO........................

MgO .......................

H20. .......................

 ' J.

41.54

2.48

1 37

.04

40.42

14.18

100. 03

K.

39.64

1 30

on

7

TC

.12

00

q7 iq

13.81

100. 38

L.

41.86

an

.24

4.15

90

38.63

14.16

99.93
224 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

14. ROCKS OF MOUNT DIABLO.

Described by Turner and Melville in Bull. Geol. Soc. Amer., vol. 2, 

pp. 383-414. Analyses by W. H. Melville. Those with record numbers 

were made in the Washington laboratory ; the others were made in the 

laboratory at San Francisco.

A. Diabase, Mitchell Canyon. Composed of augite, plagioclase, and 

ilmenite, with nralite and chlorite secondary.

B. The same rock, partly altered and partly uralitic. Called " diabase-diorite" by Turner.

C. Pyroxenite. Composed of bronzite and diallage. Equivalent to 

the websterite of North Carolina. From near Bagley Creek.

P. Glaucophane-schist, containing numerous cinnamon garnets. 

From Pine Canyon. <

A, B, 0 have the record No. 1247.

Si02 .............

TiOa .............

 AlsO3 . ............

Cr2O3 ....:.......

Fe203 ............

FeO....... .......

NiO.... ..........

MnO. .............

CaO .............

Mgo ...........:.

KsO.... ..........

NazO. ............

H20atl05°.......

H2O above 105°... 

P2O6 ... ...........

A.

52.06

.47

14.34

2.11

7.74

8.05

9.26

.73

1.74

.59

2. 90 

.13

100. 12

B.

51.58

1.05

14.99

2.04

8.36

8.59

6.51

.31

3.08

.34

2. 67 

.24

99.76

C.

53.25

2.80

.54

.69

5.93

.07

.09

16.22

. 19. 91

Trace.

 .19

.05

' . 24

99.98

D.

4-7 84

16. 88

4.99

5. 56

.56

11.15

7.89

.46

3.20

 - .17

LSI 

.14

100. 65
CLABKE AND"! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 225

E. Crystalline gabbro from Bagley Creek. Contains plagioclase and 

diallage. No. 1166.

F. Shaly gabbro. Friable, containing carbonates and sulphates. 

Somewhat resembles serpentine.

G. Shaly gabbro, like F, much resembling a true serpentine.

According to Turner, F and G are merely weathered layers of the 

gabbro.

Si02 .......................

A12O3 ...... .................

Fez03 .......... ..!.. .......

FeO.... ....................

NiO ........................

Mn0....i. .................

CaO .......................

MgO...... ................. O

K2O...... ..................

NazO.... ...................

H2Oatl05° ............ ....

H2O above 105°. ............

P205 .......................

C0a ...... ..................

S03 ........................

Organic matter ..............

E.

47.49

15. 81

1.07

4.50

.06

.41

15.53

10.39

1.16

1.20

1.83

99.45

F.

45.43

12. 55

6.50

.21

12.39

13.41

.11

1.71

2.41

2.74

Od

2.35

.24

100. 09

G.

45.69

13.30

1.85

4.72

.24

13.50

13.06

1.36

2.29

2.47

.06

1 RQ

.43

100. 86

Bull. 148 15
ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL.HS.

The following analyses are of serpentines, derived from a peridotitepyroxenite dike:

H. Almost black. Possibly derived from adjacent shale.

I. Almost black. Derived from pyroxenite.

J. Bastite. Derived from pyroxenite. No. 1166.

K. Friable serpentine.

L. Serpentine.

M. Talc like, yellowish-green serpentine.

F. Weathered serpentine. . O. Olive colored, probably serpentine.

Samples H, I, J are from near Bagley Creek. 

Arroyo del Cerro. O from Ferguson ravine, 

erable chromite.

K, L, M, N from near 

M and O carry considSiOa ... ...........

AlsOa-..-.-- ......

Cr3 03 .. ...........

Fe2 03 ............

FeO. .............

NiO ..............

MnO ........:....

CaO..... .........

MgO. ........'....

K2O.... ..........

Na2 0. ............

H2 0at 100° ......

H2O above 100° .. 

PS 06 .............

H;

38.53

14.55

2.65

4.01

.32

 3.13

21.79

 - .88

.07

4.51

9.56 

Trace.

100. 00

I.

40.50

.78

.41

4.01

2.04

.11

.13

.39

37. 43

. 16-

.28

2.81

10.94

99.99

J.

36.57-

.95--

.33

7.29

.37

 . .31

.10

.14

40.27

.31

.94

12.43

100. 01

K.

--36.96

.39

.78

5.00

2.34

- .09

3.81

33.84

.14

.34

2.16

14.02 

.02

99.89
CLARKE AND1 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS 227

Accidental organic matter was deducted from Analyses H and I, with 

subsequent recalculation of the data to 100 per cent.

.SiOs .. ............

A1303 - ............

Cr,03 ............

Fe2O3 ............

FeO.... ..........

NiO. .............

MnO .............

CaO. .............

MgO. ............

K2 0.. ...... ......

NasO. ............

H2O at 100° ......

H2 0 above 100°...

PaO, .............

SOs ..............

L34.84

.42

.68

6.08

1.85

.01

7.02

30.74

.07

.42

1.67

15.72 

.04

99.56

M.

32.27

11.45

^ 19

5.05

.19

.41

33.30

.44

12.40 

Trace.

100. 70

N.

41.52

1.57

3.50

1.07

.29

.44

36.84

3.32

12.51

101. 06

0.

30.98

1.04

34

4 88

2.01

.42

.22

38.44

.16

.40

3Q

20. 43 

Trace.

.44

100. 15
228 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

15. MISCELLANEOUS BOCKS.

A. Khyolitic obsidian, Medicine Lake, Modoc County. Collected by 

J. S. Diller, who reports it to be a banded obsidian, containing a few 

minute feldspar crystals. The banding is due to a multitude of trichites. Analysis by L. G. Eakins, record No. 1072.

B. Tuff from Hyampom, south fork of Trinity Eiver, Trinity County. 

Almost wholly made up of particles of clear glass. Collected and 

described by Diller. Analysis by George Steiger, record No. 1427.

C. Diabase-porphyrite, one-half mile west of Browns Valley, Yuba 

County. Collected and described by W. Lindgren. Contains augite, 

plagioclase, magnetite, chlorite, and epidote. Analysis by W. F. Hillebrand, record No. 1419.

D. Amphibolitic schist, 1 mile northeast of Browns Valley, Yuba 

County. Collected and described by W. Lindgren. From metamorphosis of C. Contains chiefly green hornblende and feldspar. Analysis by Hillebrand, No. 1419.

SiO2 . .............

TiO2 .............

A1203 - ............

Fe.2O3 ............

FeO.... ..........

MnO...... .......

CaO...... ........

SrO ..............

BaO.. ............

MgO ...... .......

K2 0. .............

Na2O.. ...........

Li2 0 .............

H2OatlOO° ......

H2 0 above 100°... 

P206 .............

CDs ..............

A.

73.51

14.42

.46

1.49

1.26

.33

4.29

4.03

} .40 

.04

100. 23

B.

70.40

13.50

1.31

1.61

Trace.

.56

.37

9 °,Q

2.11

1.05

7.41 

.08

100.79'

C.

48.26

C1

14.83

3.27

5 Q7

.15

11.38

Trace.

OK

8.77

1.13

1.57

.10

3.37 

.25

1.24

100. 85

D.

54.13

.46

14.53

1.50

5.25

.15

4.91

.02

10.93

00

3.53

None.

.20

4.01 

no

100. 03
CLARKE AND"! 

HILLEBBAND J

IGNEOUS AND CRYSTALLINE KOCKS. 229

E. Scoriaceous rhyolite, Mono Craters, south ofMono Lake. Described 

by Russell in 8th Ann., Part I, p. 380. Analysis by T. M. Chatard, 

record No. 36.

F. Obsidian, Mono Lake. Collected for the Educational Series of 

Eocks. Analysis by W. H. Melville, record No. 1346.

GL Pumice, Mono Lake. Educational Series. Analysis by Melville, 

No. 1346.

H. Yolcanic ash, east shore of Owens Lake. Collected and analyzed 

by Chatard, record No. 783.

SiO, .............

Ti02 .............

AlaOs.. ...........

Fe.203 ............

FeO.... ..........

MnO .............

CaO .............

MgO.. ...........

K20.. ............

NajO.... .........

H3OatllO° ......

H20 above 110° .. 

'P80B .............

CaC03 ...........

Na2S04 , soluble...

NajCOa, soluble ..

E.

74.05

13.85

.90

.07

4.31

4.60

1 2.20

99.98 .

F.

75.78

12.39

99

1.25

.81

.31

4.64

4.00

I '"

99.81

G.

67.39

15.99

.56

1.99

1.63

.77

4.80

4.74

| 2.06

99.93

H.

55.81

.80

10.07

3.43

.67

.23

1.05

2.22

2.98

.75

.65

2.50 

.27

14.44

1.45

.80

2.09

100. 21
230 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

OREGON. 

1. BASALT, MOUNT THIELSON.

Partly described by Diller in Am. Jouru. Sci., 3d series, vol. 28, p. 

257. A hyperstliene-basalt containing hypersthene, olivine, feldspar, 

and magnetite. In the printed paper only the analyses of the groundmass and the fulgurite formed in it are given.

A. Hypersthene-basalt.

B. Pyroxene.

0, D. Feldspars.

E. Groundmass.

F. A fulgurite, or lightning'tube.

Analyses A, F, by F. W. Clarke, record Nos. 108, 105. B, C, D, E, 

by T. M. Chatard, record Eos. 135,133,134,128. These analyses were 

made early in the history of the laboratory and are by no means 

complete.

SiO2 ...........

TiOs ...........

A1203 ...- .......

Fe2 03 ..........

FeO... .........

CaO.-.. .........

MgO ...........

K,0... .........

NasO. .........-

HS0... .........

P20B ...........

A.

55.68

18.93

I 8.73

7.99

4.86

.48

2.12

.60

99.39

B.

53.31

5.99

J 13. 43

3.69

21.69

98. 11

C.

55. 48

.39

26.91

1 2.32

8.11

2.27

.72

3.14

.66

100.00

D.

51.95

28.84

 » 2.24

11. 42

1.34

.59 "

3.22

.40

100.00

E.

55. 85

22.95

v 4.59

8.41

3.08

2.67

2.16

.52

Trace.

100. 23

F.

55.04

28.99

7.86

5.85

1.11

98.85

Iron oxides not separated. Analyses B, C, D, F made on very small 

quantities of material. 0 and D were analyzed by the hydrofluoric-acid 

method, and the silica was determined by difference.
CLARKE AND"! 

H1LLEBBAND.J IGNEOUS AND CRYSTALLINE BOCKS. 231

2. PERIDOTITE FEOM DOUGLAS COUNTY.

The matrix of the nickel silicate at Eiddle. Described by Diller and 

Clarke in Bull. 60, p. 21.

The rock, which may be classed as saxonite, consists essentially of 

oliviue and enstatite, with a little chromite and magnetite. Olivine 

predominates, and the eustatite forms less than one third of the mass. 

Quartz, serpentine, and genthite are present as alteration products. 

Analyses by F. W. Clarke, record Nos. 811,814, 792.

A. The fresh rock.

B. Separated olivine.

0. The genthite found in the altered rock. Probably derived from 

olivine. .

SiO8 ... .....................

Cr2 03 .............. ........

Al,0a ... ....................

FejOs ----- ........-'-...--:

FeO..... ....... ............

MnO .......................

NiO.... ....................

CaO... .....................

MgO .......................

H20 at 110° ................

A.

41.43

.76

.04

2.52

6.25

.10

.55

43.74

4.41 .

99. 80

E.

42.81

.79

2.61

7.20

.26

None.

45.12

.57

99.36

C.

44.73

} 1.18

27.57

10.56

8.87

6.99 

99. 90

3. BASALT, NEAR CRATER LAKE.

Collected by J. S. Diller, 1 mile east of the summit of-the Cascade 

Bange, on the road from Fort Klamath to Crater Lake.- A typical 

basalt, containing a considerable amount of hypersthene. Analysis by 

W. F. Hillebrand, record No. 408.

Si02 ............................ 57.47

Ti02 ....:....................... . .75

AloOs ............................ 18.86

Fe..O3 ........................... 2.21

FeO ............................. 4.08

MnO............................ .10

CaO ............................ 7.42

Sio....:::.................::..: .11

BaO

MgO.

K2O.

Na20.

H20..

.03 

4.27

.73 

3.85'

.22

.24

100. 34
232 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

ALASKA.

Eocks A to H inclusive, collected by Gr. F. Becker, who furnishes the 

petrographic data. Analyses by W. F. Hillebrand, record No. 1585.

A. Augite-brouzite-andesite, Delarof Harbor, Unga Island. Greenish black. Contains plagioclase, near labradorite, with much smaller 

proportion of augite and brouzite, in a groundmass of plagioclase, with 

a little glass and much light-green indeterminate material.

B. Augite-bronzite-andesite, St. Augustine Volcano, Cooks Inlet. 

Purplish gray. Contains labradorite, augite, and bronzite, in a groundmass of plagioclase and magnetite.

C. Quartz-porphyry, bed of Bear Creek, 4 miles from its mouth, 

Turnagain arm of Cooks Inlet. Resembles D, with more feldspar and 

less quartz.

D. Quartz-porphyry, east of mouth of Indian River, Sitka, Baranof 

Island. Contains plagioclase, quartz, a little pyroxene, and some carbonaceous matter, with secondary quartz, calcite, and muscovite.

E. Diorite, head of Captains Bay, Unalaska Island. Contains 

plagioclase, biotite, hornblende, chlorite, magnetite, and sometimes 

tourmaline.

Si02 ...........

Ti02 ...........

A12 03 ..... ......

Fe2 03 ..........

FeO... .........

NiO...... ......

MnO. ..........

CaO ...........

SrO...... ......

BaO ...........

MgO. ..........

KaO... .........

Na2O ..........

LijO. ..........

H2OatllO° .... 

H2 0 above 110°. 

P2 0fl ............

COS ... .........

C...... ........

FeSa ...........

A.

56.63

.67

16.85

3.62

3.44

Trace?

.23

7 t&

.09

4.23

2.24

3.08

Trace.

.80 

.51 

.16

None.

.06

100. 14

B.

60.40

.61

16.89

1.88

3.72

.02

.12

7 9%

.06

3.82

.77

3.80

Trace.

.09 

.20 

.16

None.

.08

99.87

C.

62.92

.84

14.29

.84

4.66

Trace.

.15

2.72

.10

3.14

1.39

4.30

Trace.

.22 

2.84 

.13

1.24

.32

100. 10

D.

65. 94

.80

13.74

.49

5.21

Trace?

.11

2.87

Trace?

.12

2.33

1.63

2.80

Trace.

.21 

2.59 

.21

.59

.20

.41

100. 25

E.

58.63

.74

16.23

1.91

4.20

.02

.11

6.59

.06

4.28

2.09

3.51

Trace.

.15 

1.17

.20

None.

.04

99.93
CLARKB AND! 

HILLEBRAND.J IGNEOUS AND CRYSTALLINE ROCKS. 233

F. Diorite, Karluk Cliffs, Kadiak Island. Contains labradorite and 

hornblende, with subordinate quartz, biotite, and magnetite.

G. Diorite, Lane and Hayward mine, Silver Bow Basin. Contains 

plagioclase, biotite, hornblende, and scattering grains of quartz, with 

secondary chlorite, epidote, and muscovite.

H. Diorite, Treadwell mine, Douglas Island. Contains plagioclase, 

mostly albite, with secondary quartz, calcite, and pyrite; the latter 

apparently replacing ferromagnesian silicates.

I. Hornblende-andesite, Boguslof Island. Described by Merrill in 

Proc. U. S. National Museum, vol. 8, p. 31. Contains hornblende, 

augite, plagioclase, tridymite, grains of iron ore, a little apatite, and 

probably sanidine.

J. Like I, but darker colored. Contains more hornblende, no glass, 

and little or no tridymite. Same locality, also described by Merrill. 

Analyses I and J, by T. M. Chatard, record Nos. 209, 210.

Si<>8 .. ..........

Ti02 ...........

AlgOs.. ..--..-'..

FeaOs ..........

FeO...... ......

NiO...... ......

MnO. ..........

CaO...... ......

SrO... .........

BaO.. ..........

MgO. ..........

KsO ......... ....

NagO. ..........

Li20 ...........

H20 at 110° .... 

H20 above 110°.

Pa08 . ..........

COa ............

FeSa ...........

F.

61.58

.63

15.89

2.19

5.50

Trace?

.20

6.49

Trace?

.06

2.69

.51

3.04

Trace.

.16 

1.26 

.12

.06

100. 38

G.

54.20

1.35

15.86

3.32

4.14

.02

.19

5.32

.04

.41

3.51

3.30

3.28

.55 

2.40 

.68

1.45

.26

100. 28

H.

63.01

.13

18.48

.06

.32

.06

2.66

.02

.06 '.39

10.01

None.

.05 

.27 

.06

2.01

2.10

99.69

I.

56.07

1.24

19.06

5.39

.92

.23

7.70

2.12

1.24

4.52

] .99 

.16

99.64

J.

51.54

.32

20.31

4.64

3.56

.32

9.55

3.16

2.47

4.29

} .«

.57

101. 07
234 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

STONY METEORITES.

1. ROCKWOOD, TENNESSEE.

From the Crab Orchard Mountains, Cumberland County, Tenn., 

about S£ miles west of Eockwood. Analyzed by J. E. Whith'eld, record 

No. 735, and described by him in Bull. 60, p. 103.

A. Analysis of the material as a whole.

B. Nickel iron separated. Forms not over 16 per cent of the mass.

C. Nodule from meteorite.

D. Portion "of nodule, 94 per cent, insoluble in hydrochloric acid. 

May be enstatite.

The stony part of the meteorite appears to be mainly pyroxene and 

auorthite. FezOs was not determined, and FeO represents the total 

iron oxide. , .

SiOa.. ............

A1203 . ............

FeO .............

CaO ..............

MgO.... .........

Fe ...............

Ni ...............

Co...............

Cu...... .........

P................

s ........ ........

Cl ...............

A.

41. 92

9.27

22.94

9.09

8.76

3.75

1.74

TV?i PA

Trace.

.65

1.58

.18

99.88

B.

87.59

12.09

Trace.

Trace.

99.68

C.

49.96

4.75

15.97

1.15

28.15

99.98

D.

51.85

4.52

13. -26

1.09

29.28

100. 00
CLARKE AND"! 

HILLEBBAND.J STONY METEORITES. 235

2. HAMBLEN COUNTY, TENNESSEE.

Mass of about half and half stone and iron found about 6 miles 

WSW. of Morristown. Analyzed by L. G. Eakins, and described in 

Bull. 113, p. 61.

A. The nickel iron. ,

B. The part of the stony portion soluble in hydrochloric acid; 37.63 

per cent, recalculated to 100, with sulphur deducted.

0. Insoluble part of the stony portion; 62.10 per cent, recalculated 

to 100.

A petrographic description of this meteorite is given by Merrill in 

Amer. Jourh. Sci., 4th series, vol. 2, p. 149,'together with an analysis 

of- the feldspar. He finds it to contain, in addition to the nickel iron, 

enstatite, diallage, anorthite, oliviue or monticellite, oldhamite or secondary gypsum derived from oldhamite, lawrenceite, troilite, and 

schreibersite.

"Fe. ...........

Ni ............

Co...........

Cu. ..........

p

S .....:......

'

A.

90.92

7.71,

.80

.19

.04

99.66

Si02 . .........

AlsO3 '.. .......

Cr2 03 ........

FeO.... ......

NiO... .......

MnO .........

CaO.. ........

MgO... ......

KaO.... ......

Na-jO .........

P205 .........

S ............

B.

45. 61

22.62

11.73

1.06

3.64

1.25

100. 00

C.

50.67

14, 89

1.32

10.55

.76

3.61

17.98

.03

.19

100. 00

3. WINNEBAGO COUNTY, IOWA.

Fell May 2, 1890. Sp. gr. 3.804, 28°.5. Analyzed by L. G. Eakius, 

record No. 1190, and described in Bull. 78, p. 95.

Composition of the mass.

Nickel iron ................................................................ 19.40

Troilite.................................................................... 6.19

Soluble silicates...........................................:................. 36.04

Insoluble silicates.......................................................... 38.37

100.00
236 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Separate analyses: 

A. The nickel-iron.

B. Silicate soluble in hydrochloric acid, calculated to 100 per cent. 

C. Insoluble silicate, recalculated to 100 per cent. The Cr2O3 probably represents chromite.

Fe ...........

Ni ...........

Co...........

P ............

S ............

A.

92. 65

6.11

65

99.41

Si02 .........

A12O3 ........

Cr203 ......:.

FeO... .......

NiO..........

MnO.........

CaO... .......

MgO ..........

KaO... .......

Na^O. ........

P2 05 .........

B.

39.74

18.42

.38

.69

40.77

100. 00

C.

55.51

5.43

.25

Q 4.K

3.00

24.09

.15

2.12

100. 00

4. TANEY COUNTY, MISSOURI.

Analysis by J. E. Whitfield, record No. 736. See Bull. 60, p. 106. 

Sp. gr. 4.484.

A. The separated nickel-iron.

B. The stony portion as a whole.

0. Silicates soluble in hydrochloric acid, recalculated to 100 per 

cent.

D. Insoluble silicates, recalculated to 100 per cent.

Fe...........

Ni ...........

Co ...........

P ............

A.

89. 41

10.41

.29

.16

100. 27

SiO2 ..........

AlsOs. ........

FeO..........

CaO..........

MgO.........

NiS ..........

FeS ..........

B.

45.88

7.89

1Q 7Q

6.02

17.96

1.67

.54

99.69

C.

26.95

17.69

35.98

15.98

3.40

100.00 '

D.

52.39

7.11

14.68

4- 4.Q

21.33

100. 00
CLAHKE AND"! 

HILLEBRAND.J STONY METEORITES. 237

5. WASHINGTON COUNTY, KANSAS.

Fell July 25, 1890. Analyzed by L. G. Eakins, record No. 1227, and 

described in Bull. 90, p. 45. 8p. gr. 3.49, 21°.6.

Composition of the mass.

........................................................... 7.7

.........................................-.......-..........' 5.0

Soluble silicates ............................................................ 46.0

Insoluble silicates .......................................................... 41. 5

Nickel-iron 

Troilite....

100.2

Separate analyses.

A. The nickel-iron.

B. Silicates soluble in hydrochloric acid, calculated to 100 j)er cent.

C. Insoluble silicates, calculated to 100 per cent.

Fe ...........

Ni ...........

Co...........

A.

86.76

12.18

.83

99.77

Si02 .........

A1203 .........

Cr2 03 ........

FeO.. ........

NiO.. ........

CoO .........

MnO.. .......

CaO .........

MgO.........

KaO. .........

Na2 0.........

B.

38.50

23.54

.69

.34

.12

36.81

100. 00

C.

53.80

4.32

1.41

11.98

4.08

22.37

.27

1.77

100. 00
238 ANALYSES OF ROCKS AND. ANALYTICAL METHODS. [BULL. 148. 

. 6. KIOWA COUNTY, KANSAS.

A pallasite found in Brenham Township. Analyzed by L. G. Eakius, 

record No. 1188, and described in. Bull. 78, p. 94. 

A. The nickel-iron. Sp. gr. 7.93, 23°.4. 

B. The pure oliviue. Sp. gr. 3.376, 23°.2. 

C. -Dark outer zone of olivine, containing troilite.

Pe'...........

Ni ...........

Co...........

Cu. ..........

P ............

S ............

^i... .........

C ............

A.

88.49

10.35

.57

.03

.14

.08

Trace?

99.66

Si02 .........

A13 03 .. .......

Fe2 03 ........

FeO... .......

NiO....'. ....

CoO .........

MnO. ........

MgO .........

S ............

LessO S...

B.

' 40. 70

Trace?

.18

10.79

.02

.14

48.02

99.85

C.

34.14

23.20

Trace.

.03

.09

40.19

5.42

103. 07 

'2.71

100. 36
n.ARKE AND"! 

HILLEltUAND.J STONY METEORITES. 239

7. TRAVIS COUNTY, TEXAS.

Analyzed by L. Or. Eakius, record No. 1097, and described in Bull. 

78, p. 91. Sp. gr. 3.543, 20°. According to Cross, the stony portion 

contains oliviue and eustatite, with a small amount of a colorless mineral, which is probably feldspar. Chromite is also present.

Approximate composition of the mass.

Nickel-iron 

Troilite....

............................................................ 2.23

............................................................ 5.03

Soluble silicates ............................................................ 39.84

Insoluble silicates .......................................................... 52.42

99.52

A. Total analysis.

B. Nickel-iron.

C. Silicates soluble, in hydrochloric acid, calculated to 100 per cent.

D. Insoluble silicates, calculated to 100 per cent.

Si02 ..... .......:.

A1.2 03 ... ..........

CrAi .........::.

CuO .............

FeO.... ..........

Fe ...............

NiO. .............

Ni ...............

Co...............

MnO. ............

CaO.... ..........

MgO .............

K2 0. ."............

Na,0.. ...........

P205 .............

S ................

H20. ......:......

LessO S .......

A.

44.75

 2.72

.52

Trace.

16.04

1.83

.52

.22--

.01

2.23

 '27:93'

.13

1.13

.41

1.83

.84

101. 11 

.92

100. 19

B.

88.74

10.68

.58

100. 00

C.

38.13

2.58

19. 76

1 1Q

1.02

37.32

Undet.

Undet.

100. 00

D.

56. 14

^ 73

1.00

9.15

q en

24.44

10

1.76

100. 00
240 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

8. BLUFF, FAYETTE COUNTY, TEXAS.

Analyzed by J. B. Whitfleld, record No. 824, and described in Bull. 

60, p. 107. Sp. gr. 3.510. Examined microscopically by G. P. Merrill, 

who reports, in addition to nickel-iron and pyrrhotite, olivine, enstatite, 

and what appears to be augite or an allied pyroxene. See Amer. Journ. 

Sci., 3d series, vol. 36, August, 1888.

A. Total analysis.

B. Mckel-iron (5.67 per cent of total). . C. Part soluble in hydrochloric acid, calculated to 100 per cent (60.62 

percent of total).

D. Insoluble part, calculated to 100 per cent (33.3 per cent of total).

SiOa... ...........

AlsOa-. ...........

FeO.. ............

Fe. ..............

NiO.. ............

Ni ...............

CoO.. ............

Co...............

MnO. ............

CaO.... ..........

MgO. ............

P2 0fi ..............

S ................

LessO S .......

A.

37. 70

2.17

23.82

4.41

1.59

.88

.16

.37

.45

2.20

25.94

.25

1.30

101. 24 

.65

100. 59

B.

82.42

15.44

2.14

100. 00

C.

33.59

1 <U

31.12

2.66

.27

.43

1.00

28.08

.42

 2.18

101. 09 

1.09

100. 00

D.

4.Q fiA

4.12

15.56

.54

A QQ

25.21

100. 00
CLARKE ANDT 

HH.LEBKAND.J STONY METEORITES. 241

This meteorite also contained a dark vein of sp. gr. 3.585, Avhich 

carried 2.30 per cent of metallic iron. Analyses, made on less than 0.4 

gram of material, gave as follows, recalculated to 100 per cent:

E. Soluble in hydrochloric acid, metal deducted.

F. Insoluble.

Si02 .................................

Al,0,. ................................

FeO.... ..................... ........

NiO + CoO ...........................

CaO.. ................................

MgO .................................

s ....................................

LessO S......... '...................

E.

27.63

2.41

34.31

3.27

32.12

.52

100. 26 

.26

100. 00

P.

56.52

1.51

12.35

4.09

Trace.

25.53

100. 00

E represents 51 and F 44 per cent of the vein.

9. SAN BERNARDINO COUNTY, CALIFORNIA.

Found in the San Emigdio Mountains. Analyzed by J. E. Whitfield, 

record Nos. 804 and 936, and described in Bull. 60, p. 114. In fragments, badly altered.

Approximate composition.

Nickel-iron ................................................................. 6.21

Soluble silicates, etc ........................................................ 51.26

Insoluble silicates........................................................... 42.23

99.70

The soluble part was probably olivine and pyrrhotite, with secondary 

iron oxide. The insoluble part was enstatite, essentially. 

A. The nickel-iron. 

B. The enstatite.

Fe. ..............

Ni ...............

Co...............

A.

88.25

11.27

.48

100. 00

SiO,... ...........

FeO..............

CaO--...... ..--.-

MgO.............

B.

KA A.O

14.03

2.46

, 29.11

100. 02

Bull. 148- -16
242 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

10. BEAVER CREEK, BRITISH COLUMBIA.

Fell May 26, 1893, near Beaver Creek, West Kootenai district. 

Described by Howell, Hillebrand, and Merrill in Amer. Journ. Sci., 3d 

series, vol. 47, p. 430.

Composition of the mass.

Nickel-iron ................................................ 17.13

Magnetite ................................................. .16

Troilite.......................... ..---...---...--.......... 5.05

Soluble silicates and phosphate ............................ 37.23

Insoluble silicates and chromite............................ 40.43

100.00

According to Merrill, the silicates visible are olivine, enstatite, probably a little plagioclase, and some glassy base.

Analyses by W. F. Hillebrand, record No. 1444.

A. Nickel-iron.

B. Nonmagnetic, stony portion.

C. Portion of B soluble in hydrochloric acid, calculated to 100 per 

cent.

D. Insoluble portion, calculated to 100 per cent. From 0 and D troilite and chromite are excluded. The chromite forms about 0.75 per 

cent of the stony matter.

Fe .....

Ni .....

Co .....

Cu.....

A.

90.68

8.80

.49

.03

100. 00

siOs .....:...

TiO2 .... .....

A12 03 ........

Cr2O3 ........

FeO... .......

Fe... ........

NiO. .........

MnO .........

CaO .........

MgO... ...... O

K2O... .......

Na,2 0. ........

H2 0.. ........

PsOfi .........

S ............

Cl ...........

Troilite ......

Chroruite.... .

B.

45.87

09

2.30

. .51

12.68

3.87

.07

.26

1.96

28.24

.15

.98

.34

.30

2.21

99.83

. Uo 

.75

C.

38.26

.56

19.52

.09

.27

1.03

38,74

.02

.13

.70 

.68

100. 00

D.

57. 75

.18

4.89

8.02

.35"

3.44

23.19

.25

1.87

.06

100. 00
CLAEKE AND") 

HILLBBRAND.J STONY METEORITES. 243

11. LLANO DEL INCA, CHILL

Analyzed by L. G. Eakins, record No. 1201, and described in Bull. 78, 

p. 97.

Approximate composition.

Nickel-iron .................................................. 25.8

Troitite......................'.:.............................. 10.6

Soluble silicates ............-............------.-.........--- 30.9

Insoluble silicates ...... ............ ................ i........ 32.6

99.9

Separate analyses.

A. The nickel-iron.

B. Silicates soluble in hydrochloric acid, calculated to 100 per cent.

C. Insoluble silicates, calculated to 100 per cent.

Is the P2O5 in B derived from schreibersite?

Fe ...........

Ni ...........

Co...........

A.

89 77

9.17

.61

99.55

 SiOs..........

A1203 ........

Cr.203 ........

FeO .........

NiO... .......

MnO. ........

CaO .........

MgO.........

P2 06 .........

B.

28.08

12.74

42.52

2.90

.20

9.33

1.98

2.25

100. 00

C.

53.11

2.32

.90

1 B CO

1.75

23.10

100. 00
244 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

METEORIC IRON.

A. The Mount..Joy meteorite. From near Two Taverns post-office, 

near Gettysburg, Pa. Analysis by L. Gr. Eakins, record No. 1318.

B. From Pulaski County, Va. Sp. gr. 7.95,23°. Analysis by Eakins, 

No. 1228. Described by EakiDS in Bull. 90, p. 45.

0. From Ellenboro, Eutherford County, N. C. Described and 

analyzed by Eakins, Bull. 78, p. 93. Eecord No. 1160.

D. From Linnville Mountain, North Carolina. Analyzed by J. E. 

Whitfield, record No. 822, and described in Bull. 60, p. 107. Sp. gr. 

7.778.

E. From Cherokee County, Ga. Analysis by H. N. Stokes, record 

No. 1527.

Fe .............

Ni .............

Co .............

Cu. ............

P ..............

s. ..............

Si

C ..............

A.

93.80

4.81

.51

.005

.19

.01

90. 325

B.

93.59

5.56

.53

Trace.

.27

.01

Trace.

99.96

C.

88.05

10.37.

.68

.04

.21

.08

.02

99.45

D.

84.56

14.95

.33

Trace.

.12

None.

99.96

E.

91.96

6.70

.50

.03

.11

.01

Trace.

Trace?

99.31
CLARKE AND"! 

 HILLEURAND.J METEORIC IRON. 245

F. From near Holland's Store, Cliattooga County, Ga. Analysis by 

J. E. Whitfield, record No. 765. See Bull. 60, p. 106. Sp. gr. 7.801.

G. From Hamilton County, Tex. Sp. gr. 7.95,27°. Analysis by L. G. 

Eakins, record No. 1189. See Bull. 78, p. 95.

H. From near Scottsville, Alien County, Ky. Analysis by Whitfield, 

record No. 509. See Bull. 55, p. 64.

I. Fell 6 miles east of Cabin Creek, Johnson County, Ark., March 

27,1886. Analysis by Whitfield, record No. 505. See Bull. 55, p. 63.

J. From near Grand Rapids, Mich. Sp. gr. 7.87. Analysis by E. B. 

Riggs, record No. 296. See Bull. 42, p. 94.

Fe. ............

Ni .............

Co.............

Cu. ............

Mg... ..........

Mn. ............

P ..............

S.... ...........

Si..............

C ..............

P.

94.60

4.97

'.21

.21

99.99

G.

86.54

12.77

.63

.02

.16

.03

.11

100. 26

H.

94.32

5.01

Trace.

.16

34

.12

99.95

I.

91.87

6.60

Trace.

.41

.05

.15

.34

99.42

J.

88.71

10.69

.07

.02

.26

.03

.13

99.91
246 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

K. The El Capitan iron, from near Bonito, N. Mex. Analysis by 

H. K. Stokes, record No. 1527.

L. From La Bella Eoca, Sierra de San Francisco, Mexico, State of 

Durahgo. Analysis by J. E. Whitfield, record No. 1037. Bull. 64, 

p. 28.

M. Troilite nodule from L, outer part, somewhat altered.

N. Troilite nodule M, inner part. Analyses L and M also by Whitfield, record No. 1037.

O. From Puquios, Chile. Sp. gr. 7.93, 25°.2. Analysis by L. G. 

Eakins, record No. 1181. See Bull. 78, p. 95.

P. The Abert iron, of unknown origin. Analysis by E. B. Eiggs, 

record No. 356. Sp. gr. 7.89. See Bull. 42, p. 94.

Fe .............

Ni ...... .......

Co.............

Cu...... .......

P ..............

S ..............

Si. .............

C ..............

NiS ............

FeS.. ..........

FesOs ..........

K.

90.51

8.40

.60

.05

.24

99.80

L.

91.48

7.92

.22

.21

.21

.06

100. 10

M.

2.07

37.51

' 37.80

19.85

- 97. 23

N.

9.37

2.13

85.27

96.77

0.

88.67

9.83

.71

.04

.17

.09

Trace?

.04

99.55

'P.

92. 07

7.01

.66

.08

.01

.05

99.88

The two following meteoric irons were analyzed by L. Gr. Eakins in 

the Denver laboratory.

A. Found near Albuquerque, N. Mex. Described by Eakins in Proc. 

Colorado Sci. Soc., vol. 2, p. 14.

B. From Wyoming. Partial analysis.

-

Fe ...................................

Ni ...................................

Co ...................................

Cu.... ...............................

Zn.... ...............................

Mn...................................

P ....................................

S ....................................

Si....................................

r<

A.

88.76

9.86

.51

.034

.03

Trace.

.182

.012

044.

Undet.

99. 432 .

B.

89.26

5.94

.78

.24

96.22
CLARKE ANDT 

HILLEBEAND.J SANDSTONES AND CHERTS. 247

SANDSTONES AND CHERTS. 

SANDSTONES FROM OHIO.

A. Blue sandstone from near Cleveland. Analysis by T. M. Chatard, 

record No. 214.

B. Sandstone from Berea. Analysis by L. G. Eakins, record No. 914.

0, D7 B. Three samples of the " Peebles-Henley sandstone," from 

Portsmouth. Analyses by H. K. Stokes, record No. 1239. Alkalies, 

etc., undetermined.

-

SiOa.. ..........

AlaOa. ..........

Fes03 ..........

FeO.. ...........

CaO... .........

MgO.... ....... O

KaO.... ........

NJteO. ..........

H2 0... .........

Insbl. iuHCl...

A.

91.67

6.92

.28

CM.

1.17

100. 38 

97.50

B.

92.91

3.78

91

.31

.61

'.34

1.19

100. 05

C.

t)0 4-0

5,15

.65

. .27

.28

.99

97. 74 

98.00

D.

89.32

5.52

.87

.35

.51

1 4.Q

98.06 

qfi QO

E.

87.12

5.96

.85

.85

.73

2.00

97.51 

95.52
248 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

, SANDSTONES FROM CALIFORNIA. 

1. SANDSTONES FKOM MOUNT DIABLO.

Described by Turner and Melville in Bull. Geol. Soc. Amer., vol. 2, 

pp. 383-414. Analyses made by W. H. Melville in the San Francisco 

laboratory.

A. Upper Cretaceous, Chico sandstone. Light brown, finely granular, carrying grains of mica and feldspar.

B. Lower Cretaceous, Eeocomian sandstone. Hard, granular, greenish. From headwaters of Bagley Creek.

C. Miocene sandstone. Granular, particles light brown and black, 

friable. From near Wall Point.

D. Chico sandstone. Greenish gray, compact, crystalline.

SiO3 .............

A1203 . ............

Fe2O3 ............

FeO... ...........

MnO. ............

CaO. ...... ......

MgO .............

o

K2 0...... ........

Na,0. ............

H.OatlOO0 ......

H.;0 above 100°... 

P2 0ft .............

CO-2-... ..........

A.

73.71

10.40

3.89

1.88

.17

.96

1.62

.99

3.48

1.06

2.60

100. 76

B.

56.84

11.37

1.46

4.95

.22

7.62

3.10

.86

3.26

1.45

3.34 

.10

5.10

99.67

C.

44.54

12.63

2.50

3.08

.44

14.65

5.55

1.37

- 3.35

1.43

2.25 

.29

7.76

99.84

D.

36.93

7.22

1.59

2.95

.57

29.34

2.34

.64

2.94

.57

3.45 

.16

* 11. 30

100. 00

* COz determined by difference.

Traces of organic matter are found in all four sandstones, but were 

not determined.
CLARKE AND! 

HILLKBRAND.J SANDSTONES AND CHERTS. 249

2. SANDSTONE DIKES IN SHASTA COUNTY.

Described by J. S. Diller, in Bull. Geol. Soc. Arner., vol. 1, p. 411. The 

rock is made up of quartz, feldspar, and biotite, with a calcite cement. 

Serpentine, spheiie, magnetite, and zircon also occur in it, but are less 

common.

A. From Salt Creek, one-half mile above McNett's.

B. One and one-fourth miles below Ono Bridge, North Fork of Cottonwood.

C, D. Three-fourths of a mile below John Alien's, Dry Creek.

E. From John Alien's, Dry Creek.

Analyses A, B, by T. M. Chatard, record No. 1106. C, D, E, by 

J. E. Whitfield, record Nos. 972,973.

Si03 ...........

TIG- ............

Al,03 -.-. .......

Fe,O3 ..........

FeO...... ......

MnO. ..........

CaO ...........

BaO ...........

MgO... ........

KaO ............

NaaO... ........

H.20 at 110° ....

H3 0 at red beat. 

C02 . ...........

PaOfi ...........

S03 ............

Cl .............

A.

48.13

.24

11.19

1.25

1.47

.29

16.39

.04

2.22

1.17

2.29

.78

1.78 

12.73

.14

100. 11

B.

48.10

.47

12.16

1.02

2.14

.26

15.88

Undet.

1.65

1.56

2.46

.46

3.27 

10.36

.13

99.92

C.

59. 10

.70

14.02

3.16

1.42

9.35

3.72

1.49

2.21

2.63 

4.65

100. 45

D.

61. 60

Trace.

12. 15

2.09

3.30

Trace.

6.92

2.33

1.41

2.16

3.10

5.05 .

.08

.27

100. 46

E.

54.55

Trace.

10.64

1.59

1.16

1.53

14.30

1.29

1.68

2.60

1.60 

9.05

.10

.10

.72

100. 31
250 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

The following bedded sandstones of the same region are also 

described:

F. From Middle Fork of Cottonwood, 1 mile above Miller's.

Gr. Top of cascade, 1£. miles up Byron Creek from North Fork of 

Cottonwood.

H. Two and one-half miles above John Alien's, Dry Creek.

Analyses F and Gr, by Chatard, record No.' 1106. H, by Whitfield, 

record No. 974.

SiOs ...... ..................

TiO3 ...........'...... .....

A1203 . ......................

Fe203 ......................

FeO.. ......................

MnO. ......................

CaO,.. .....................

BaO...... ..................

MgO. ......................

K80...~. ..................

NasO. ......................

H2O at 110°.... ............

COa...... ..................

P205 .......................

S03 ........................

CL... ......................

P.

55.85

.76

13.20

2.56

4.77

.24'

6.93

Undet.

1.90

1.89

2.60

1 1Q

2.99

4.97

.18

99.97

G67.62

.48 .

13.63

1.25

3.27

.15

2.80

.03

2.34

1.11

2.78

fi4

2/83

.72

.08

99.73

H.

60.74

.86

10.25

4.31

6.21

Trace.

4.97

3.69

.52

1.83

4.36

2.29

Trace.

.40

Trace.

100. 43

3. SANDSTONE FROM SULPHUR BANK.

Described by Becker in Mou. XIII, p. 92. Analysis made by Melville 

in the San Francisco laboratory. An altered sandstone, showing grains 

of quartz, plagioclase, and orthoclase.

SiOj.. ..........

TiO3 ...........

A1203 .. .........

Fe203 ..........

FeO............

MnO...........

CaO............

MgO...........

68.50

.60

12.82

1.29

3.37

.02

1.82

2.21

KaO. ...........

Na2O... ........

H2OatlOO° ....

H.2 0 above 100°.

P2 0«. ............

1.26

6.03

.28

2.11

.16

100.47
CLARKE AND"! 

HILLKBEAND.J SANDSTONES AND CHERTS. 251

MISCELLANEOUS SANDSTONES.

A. Triassic sandstone from the Jaittelle quarry, near Hancock, Md. 

Hard, compact, brown. Analysis by F. W. Clarke, record No. 613.

B. Brown sandstone, Hummelstown, Pa. Analysis by B. A. Schneider, record No. 1280.

C. Yellow sandstone from Stony Point, Mich. Analysis by F. W. 

Clarke, record No. 213.

D. Carboniferous sandstone adjoining the peridotite dike of Elliott 

County, Ky. See Diller, Amer. Jouru. Sci., 3d series, vol. 32, p. 125. 

Analysis by T. M. Chatard, record No. 354.

E. Yellow sandstone, Armejo quarry, Colorado. Analysis, partial, 

by T. M. Chatard, record No. 289.

SiOa... ..........

TIG* ...........

A1203 .. .........

 FesOa ..........

FeO...... ......

MnO...........

CaO...... ......

MgO ...........

KaO...... ......

Na20 .:.........

H2OatlOO°..... 

H20 above 100°. 

PaOB . ..........

coa ...... ......

Insol. in HC1...

A.

76.43

1 17.78

.84

.92

Undet.

Undet.

1 2.79

98.76 

88.68

B.

88.13

5.81

1.77

.31

.20

.53

2.63

.06

.23 

.26

99. 93

C.

84.57

5/90

6.48

.68

Undet.

Undet.

| 1.92

99.55 

91.87

D.

60.78

.03

10.54

3.27

.10

10. 16

1.59

2.36

1.41

.85 

2.32 

.09

6.29

99.78

E.

81.27

9.81

1.44

.44

.42

Undet.

Uudet.

| 1.19

94.57 

95.54
252 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Potsdam sandstone, Sauk County, Wis. Analysis by E. A. 

Sclmeider, record No. 1280.

Gr. Banded sandstone, Peoa, Utah. Analysis by Schneider, record 

No. 1280.

H. Brown sandstone, Flagstaff, Ariz. Analysis by T. M. Ohatard, 

record No. 1144.

I. Sandstone, Robinson mine, Summit County, Colo. Analysis by 

L. G. Eakins, made in the Denver laboratory, partial.

SiOa...... ........

AlaOs...... .......

Fe2 0:, ............

CaO .............

MgO.... .........

o

KsO. .............

NasO. ............

H2OatlOO° ...... 

H2O above 100° . . . 

COa...... ........

F.

99.42

\ - 81

} . u

99.91

G.

96.60

| 2.02

.04

.08

.11

.20

99.14

H.

*79. 19 '

1.30

2.45

7.76

. .23

.32 

2.94°

5.77

99.96

I.

56.33

.77

97

14.01

7 3ft

Undet.

Undet.

Undet. 

Undet. 

1 19 04

98.42

; Silica and insoluble matter. t Calculated for bases.

CHERT.

From the lead-zinc region of southwestern Missouri and its extension 

into Kansas.

Collected by W. P. Jenney.

A. Unaltered chert, East Hollow, Belleville, Jasper County, Mo. 

B. Partly altered, same locality. 

C. Altered to "cotton rock," same locality. 

D. From the Surprise mine, Joplin, Mo. 

Analyses by E. A. Schneider, record No. 1205.

SiOa.- - ........

A12O3. Fe3O3 .---..

CaO..............

MgO.............

A.

98.17

.83

.05

.01

.78

99.84

B.

98.92

.48

.03

.02

.42

99.87

C.

98.71

.43

.03

.02

.50

99.69

D.

99.46

.29

.04

Trace.

.34

100. 13
CLARKK AND"! 

HILLEHKAND.J SANDSTONES AND CHERTS.

E. Blue chert, unaltered, Bonanza shaft, Galena, Kans. 

F. Same locality. 

G. Altered, same locality. 

H. " Jasperite," Joplin, Mo. 

I. "Jasperite," Galena, Kans.

Analyses E, F, G, by E. A. Schneider, record No. 1205. H and I, by 

L. G. Eakius, record No. 1208.

SiOa ...........

AlaOa. Fe2 03 . 

CaO ...........

MgO.... .......

E.

99. 23

.22 

.02

.50

99.97

P.

98.60

.52 

.10

Trace.

.40

99.62

G.

99.13

.16

.01

.20

99.50

H.

95.77

1.84 

.54

.24

1.17

99.56

I.

97.33

1.89 

.11

.09

.77

100. 19
254 ANALYSES OP EOCKS AND ANALYTICAL METHODS. [BULL. 148.

THE CARBONATE ROCKS: LIMESTONE, DOLOMITE, SIDERITE, ETC.

VERMONT AND MASSACHUSETTS.

A. White marble, Eutland, Vt. Analysis by L. G. Eakins, record 

No. 1213.

B. The portion of A insoluble in dilute hydrochloric acid. Same 

analyst and number.

C. White marble, Lee, Mass. Analysis by E. A. Schneider, record 

No. 1279.

D. Limestone, Lee, Mass. Collected by B. K. Emerson. From cut 

on west side of railroad. Analysis by George Steiger, record No. 1654.

B. Dolomite, Oharlemont, Mass. Collected by Emerson. Analysis 

by Eakins, record No. 1343.

F. Dolomite, Webster, Mass. Collected by Emerson. Analysis by 

H. N. Stokes, record No. 1634.

SiO2 ... .........

AlsOs. ..........

Fej03 ..........

FeO...... ......

MnO.. .........

NiO-- ..........

CaO... .........

MgO ...........

KaO... .........

Na2O.... .......

HsO.. ..........

Pa06 ... .........

COs... .........

SO3 ............

A.

8.00

.39

.14

50.79

Trace.

1.01

39.80

100. 13

B.

56.69 

31.16

2.13

2.68

3.27

Undet.

Undet.

95.93

C.

1Q

} .»

30.88

21.42

46.72

99.45

D.

.95 

OQ

.10

54.75

.56

.15

.02

.08

.03

43.38

.05

100. 16

'E.

.67

T^Tn PA

.08

7.60

1.61'

.03

28.63

16.17

45.35

100. 14

F.

1.01 

.17

"NTfYii A

.37

.08

30. 82

21.35

.10

.01

no

.06

4.^ 84-

99.90
CLARKE AND"! 

H1LLEBRAND.J THE CARBONATE ROCKS. 255

NEW YORK, PENNSYLVANIA, MARYLAND.

A. Dolomite-marble, New York Quarry Company, Tuckahoe, Westchester County, N. Y. Analysis by W. F. Hillebrand, record No. 746.

B. Hydraulic cement-rock, Akron, N. Y. Analysis by George Steiger, 

record No. 1655.

C. Compact gray limestone, Greason, Pa. Analysis by E. A. Schneider, record No. 1279.

D. Dolomite-marble, Cockeysville, Md. Analysis by Schneider, No. 

1279.

E. An earlier sample of D. Analysis by J. E. Whitfleld, record 

No. 827.

Insoluble. ......

Si03 .. ......... .

TIG* ...........

Al,03 --.. .......

Fe2O3 ..........

FeO.... ........

CaO. ...........

MgO ........... O

K20 -I.........

NaaO.... .......

H,0.... ........

P206 ............

CO, ............

Organic matter.

A.

1.33

.21

30.68

20.71

.16

46.66

99.75

B.

9.03

.16

2.25

.85

.52

26.84

18.37

.85

.98

.03

40.33

100. 21

C.

11.07

39.26

9.00

.18

38.82

.75

99.08

D.

5.57

1 .40

29.08

20.30

44.26

99.61

E.

.44

1.22

Trace.

30.73

20.87

1.22

45.85

100. 33
256 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

VIRGINIA AND WEST VIRGINIA.

A. Limestone, upper ledge, Moundsville Narrows, W. Va.

B. Same as A, lower ledge. Analyses A and B by T. M. Chatard, 

record No. 127.

0. Trenton limestone, Lexington, Va. Analysis by R. B. Riggs, 

record No. 365.

D. Limestone, Staunton, Va. Analysis by George Steiger, record 

No. 1630.

E. Part of D, insoluble in one-tenth hydrochloric acid.

F. Soluble part of D. Analyses E and F also by Steiger, same number. These three analyses are accompanied by analyses of the residual 

clay, formed by the weathering of the limestone. See section on clays.

SiOa . ...........

TiOa ...........

AlsO3 ... ........

Fe2 03 ..........

FeO. ...........

MnO ...........

CaO... .........

MgO ...........

KaO. ...........

Na2O. ..........

H2OatlOO° .... 

H20 above 100°.

PA.- - ......

CO2 ...... ......

A.

10.33

.90

Trace.

48.02

1-.08

1 .05 

Trace.

39. 18

99.56

B.

1.53

.96

53.26

.93

} «>

Trace.

43.16

99.94

0.

.44

.42

54.77

] 1.08

42.72

99.43

D.

7.37

OQ

1.92

.29

.63

28.39

18.30

. 1.09

OQ

.09 

.49 

.03

41.85

100.63

E.

6.98

.09

1.39

.25

None.

.04

.15

.91

.04

Unclet. 

.15 

None.

10.00

F.

.39

.53

.04

.63

None.

28.35

18.15

.18

05

Undet. 

.34 

.03

41.85

90.54
CLARKE AND"] 

HILLEBBAND.J THE CARBONATE ROCKS. 

GEORGIA.

257

A. Marble, Happy Valley.

B. "Creole" marble, Happy Valley.

0. Portion of B insoluble in dilute hydrochloric acid.

D. "Cherokee" marble, Happy Valley.

B. Portion of D insoluble in dilute hydrochloric acid.

Analyses by L. G-. Eakins, record Nos. 464, 485.

SiOB .. .......... 

Als03 . ..........

Fe3 03 ..........

FeO...... ......

CaO...... ......

MgO........... O

H80...... ......

C02 .. ..........

A.

2.23 

.91

.22

52.16

2.09

AK

 42.22

100. 28

B.

1.84

.17

.05

53.91

.83

.13

43.16

99.69

C.

58. 21 

7.37

.31

12.53

20.42

98.84

D.

2.01

.15

.06

53.69

.83

.17

43.13

100. 04

E.

55.48 

15.58

Trace.

14.52

12.88

98. 46

Bull. 148 17
258 ANALYSES OF EOCKS AND ANALYTICAL METHODS. [BULL. 148.

TENNESSEE, ALABAMA, LOUISIANA.

A. Limestone, »Kuoxville, Tenu. Analysis by L. G. Eakins, record 

No. 1159. . B. Knox dolomite, Morrisville, Ala. Described by Eussell in Bull. 

52, together with a residual clay derived from it. See section on clays. 

Analysis by W. F. Hillebrand, record Ko. 797.

C. Limestone from Eayborn's salt-lick, Bienville Parish, La. Analysis by E. B. Eiggs, record No. 323.

D. White marble, streaked with black. From 5 miles west of Winnfield, La. Analysis by W. F. Hillebrand, record No. 760. In addition to the constituents named in the table, this marble contains traces 

of barium, strontium, chlorine, and organic matter.

Insoluble .........

 SiOa.. ............

Ala08 .. ...........

Fe2 03 .-.. ........

FeO.... ..........

MnO. ............

CaO. ...... ......

MgO. ............

HsO...... ........

PS06 . --- --. ......

COS . .............

S03 ..............

A.

.17

.04

93

KK Art

Of)

91

A 9 CO

100. 05

B.

q OA

.17 .

.17

.06

29. 58

20.84

30

45.54

99.90

C.

| 1.61

M OQ

.06

.05

44.12

.05

100. 53

D.

.65

Trace.

.10

55.01

.60

.13

43.43

.27

100.19 .
CLARKE AND"] 

HILLKBBAND.J THE CARBONATE ROCKS. 

FLORIDA.

259

Coral and shell rocks, collected by 1ST. S. Shaler. Partial analyses 

only. Chlorides and sulphates present; alkalies and phosphates not 

looked for.

A, B, C, D. Coquina' gravel, Tortugas.

E. The same, Key West.

Analyses by F. W. Clarke, record No. 878.

SiOs ... .........

AlaO3, Fe2O3 ---- 

CaO. ......--.-.

MgO ...........

C02 ...... ......

HaO.... ........

A.

.19

.19 

52.24

1.53

41.46

3.27

98.88

J3.

.22

.47 

51.24

2.09

41.07

3.57

98.66

C.

.32

.56 

49. 38

1.93

40. 39

5. 12

97.70

D.

.21

' .76 

51.95

1.44

41.53

3.07

98.96

E.

.25

.56 

51.52

»2.08

41.58

3.19

99.18

F. Near Fort Worth.

G. East side of St. Johns Eiver, near Seville.

H. Corroded surface, Miami Eeef.

I. Near Oak Hill.

J. Near Melborne.

Analyses by F. W. Clarke, record No. 885.

Si02 ...... ......

Al203,Fe2O3 .... 

CaO............

MgO ...........

COa ............

H2O. ...........

F.

2.94

.23 

51.51

.71

41.59

2.64

99.62

G.

8.50

.73 

47.29

1.51

39.00

3.37

100. 40

H.

2.99

.65 

51.22

.06

41.22

2.23

98.37

I.

5.87

.95 

50.34

.37

39.62

3.21

100. 36

J.

17.83

1.18 

43.85

.26

34.31

2.53

99.96
ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

K. Coarse shell mass, Senote. 

L. Coral rock, Salt Key Bank. 

M. Loggerhead Key.

Analyses by L. G-. Eakins, record No. 882. The following analyses, 

also by Eakins, No. 883, are included for comparison: 

N. Coralline bottom, Barbados. 

O. Recent coral (Siderostria), Bermuda.

Si02 . ...........

AlsOa.. .........

PeaO3 ..........

CaO. ...........

MgO ............

o

C02 . ...........

H20... .........

K.

.22

\ "

54.87

.64

43.89

.11

99.91

L.

.11

1 .04

53.54

.71

43. 87

1.13

99.40

M.

.20

j .22

53. 54

.78

43.71

.81

99.26

N.

1.17 K""

46.45

5.15

43.40

2.73

99.21

0.

.23

55.16

.20

43.74

.54

99.87

OHIO.

A, B, C, D. Trenton limestone from New Vienna. 

Partial analyses by F. W. Clarke and B. B. Biggs, record Nos. 729, 

730, 732. Iron and alumina are present in soluble form.

CaO .............

MgO.............

C09 ... ...........

A.

8.47

47. 16

1.5'

36.20

92.35

B.

9.93

49.04

.58

37.64

97.19

C.

2.12

51.18

3.08

42.04

98.42

D28.43

23.00

12.90

30.82

95.15
CLARKE AND"! 

H1LLEBRAND.J THE CARBONATE ROCKS. 261

E. Trenton limestone, Arcadia, Hancock County.

F. Air-line Junction, Toledo. This sample contains a good deal of 

ferrous carbonate..

G. Gas-rock, St. Henry's well, Mercer County.

H. Oil-rock, Lima.

All Trenton. Analyses, partial^ by Clarke and Kiggs, record Nos. 

729,730.

CaO.... ..........

MgO. ............

C08 ...... ........

E.

8.56

47.17

2. 59

38.54

96.86

F.

3.52

30.64

18.05

42. 82

95.03

G.

2.27

50.34

2

QR

40.96

96.43

H.

1.64

32.24

17 QC

43.92

95.16

The following partial analyses by F. W. Clarke, record No. 7387 all 

relate to Trenton limestones: 

A. Well No. 3, Bryan. Gas-rock. 

B. McElree well, Kenton. Depth, 1,33 5 feet. 

C. Huntsville. Depth, 1,405 feet. 

D. Prospect. Depth, 1,650 feet. 

E. Findlay street well, Dayton. Depth,' 975 feet. 

F. Xenia. Depth, 1,075 feet. 

G. New Madison. Depth, 1,150 feet.

Fe.3 03, A13O3 ......

CaC03 - ...... ....

MgCo3 ...........

Fe203 , A1203 ......

CaC03 ...........

MgCOs. ..........

A.

9.22

1 K1

49.00

38.59

98.32

B.

5.26

1.10

QA OO

8.43

99.11

E.

12.34

.58

82.36

1.67

96.95

C.

4.41

0 -IK

KT OO

OO 1 C

98.95

P.

9.23

.18

86.54

2.99

98.94

D.

9ft 19

9 K7

cc r\o

Q 77

98.58

G.

11.11

3.60

64.91

17.98

97.60

In C and G there is ferrous carbonate.
262 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

Partial analyses by Charles Catlett, record Nos. 754, 755, 756, 757; 

all of Trenton limestones from the natural-gas belt.

A. London. Depth, 1,594 feet. . ' '

B. Air-line Junction, Toledo. Depth, 1,415 feet.

C. Celina. Depth, 1,112 feet.

D. City well No. 2, Upper Sandusky.

E. Sandusky. Depth, 2,260 feet.

F. Gas-rock. Pauck well, St. Marys Township, Auglaize County.

G. Gas-rock. Bennett well, St. Marys Township. Depth, 1,121 feet.

H. First city well, Carey. Depth, about 1,350 feet.

I. Well No. 2, Fort Recovery. Depth, 1,065 feet.

J. Waggoner well, 6 miles west of Fremont. Gas-rock.

K. Loomis and Nyman well, Tiffin. Depth, 1,470 to 1,481 feet.

L. Loomis and Nyman well, Tiffin. Depth, 1,488 to 1,494 feet.

M. Port Clinton. Depth, 1,660 to 1,700 feet.

N. Wauseon. Depth, 2,135 feet.

O. Napoleon. Depth, 1,830 feet.

P. Kossuth, Alien County. Oil-rock.

Q. Doenze's well, Franklin Township, Mercer County. Depth, 1,107 

feet.

Insoluble. ......

Al203,Fe2 03 ..... 

CaC03 .........

MgCOs.........

Al203,Fe203 .... 

CaC03 .........

MgC03 .........

Al203,Fe203 .....

CaCOs.. ........

MgC03 .........

4

A.

15.90

1.84 

77.69

1.89

97.32

G.

1.66

2.48 

56.94

35.55

96.63

B.

° 2.88

8.68 

54.68

25.73 

91.97

H.

5.72

3.08 

80.11

8.09

97.00

M.

7.46

4.16

71.96

14.34

97.92

C.

2.95

2.95 

68.41

24.18

98.49

I.

1.89

1.57

87.88

7.43

98.77

N.

18.24

7.28

42.82

28.11

96.45

D.

8.18

4.31 

64.25

15.93

92.67

J.

5.22

6.32 

52.93

32.75

97.22

0.

2.66

2.14

53.85

37.33

95.98

E.

3.65

4.58 

54.62

33.67

96.52

K.

5.66

4.86 

52.89

33.46

96.87

P.

1.08

.66

90.72

6.69

99.15

F.

3.18

3.12 

52.18

38.42

96.90

L.

9.88

1.46 

79.39

6.20

96.93

Q.

3.68

8.38

69.53

10. 98

92.27
CLARKE AND"] 

HILLEBRAND.J THE CARBONATE BOOKS. 

INDIANA.

263

A. Buff limestone, Hoosier Stone Company, Bedford.

B. Blue limestone, same locality.

Analyses by F. W. Clarke, record Nos. 306, 307.

SiO,-- .................................

Fe.2O:1 ................................

CaO...... ............................

MgO ..................................

PB06 ..,. .'-......... ..---..

COB..................................

S03 ..................................

A.

.63

.39

54.19

.39

44.01

None.

99.61

B.

1.69

.49

54.18

.37

43.08

None.

99.81

The following Trenton limestones are all from the natural-gas belt: 

0. Union City. Depth, 1,160 feet. 

D. Bluffton. Depth, 1,062 to 1,067 feet. 

E. Muncie. Depth, 920 feet. 

F. Greeusburg. Depth, 867 feet. 

G. Yernou. Depth, 905 feet. 

H. Wabash. Depth, about 900 feet.

Analysis C by F. W. Clarke, record No. 738. The remainder by 

Charles Catlett, Nos. 753, 758.

AlaOs.FeiOo .... 

CaC03 .........

MgC03 . ........

C.

2.14

1.23 

83.21

12.48

99.06

D.

2.37

4.48 

53.43

37.47

97.75

E.

3.30

3.72 

51.96

38.11

97.09

P.

.87

.55 

Qd fiO

.36

96.38

G.

8.00

:eo

85.56

94. 16

H.

3.52

7.58 

53.18

30.53

94.81
264 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

MISSOURI.

Limestones and dolomites collected by W. P. Jenney. Analyses by 

L. G. Eakins, record Nos. 1184,1207. CO2 calculated. 

A, B. Cherokee limestone, quarry near Seneca, Newton County. 

C, D. The same, from near G-rand Falls, Newton County. 

E, F. Dolomite, Oswego land, Joplin.

A12 03 - ...... ....

FeO............

MnO. ..........

CaO............ 

MgO....... ....

C03 ...... ......

A.

.66

.11

fiK

55. 29 

.23

43.69

100. 03

B.

1.21

.13

.07

54.92 

.20

43.31

' 99. 84

C.

1.01

.08

.05

.03

54.98 

.31

43.54

100. 00

D.

1.01

.13

Trace.

55.11 

.32

43.65

100. 22

E.

29.77

| 1.32

21.46 

14.79

33.13

100. 47

F.

11.66

| 1.03

28.72 

17.26

41. 55

100. 22

KANSAS.

, A. Limestone from Silverdale. Analysis by Charles Catlett, record 

No. 967. . .

B. Cherokee limestone, Short Creek, near Spring River, Cherokee 

County. Analysis by L. GL Eakins, record No. 1184.

Insoluble. ...,......................_.

Si02 .... ..............................

AlsOs-. ...............................

FeaOs ............ ....................

FeO.'.. ...............................

MnO. ................................

CaO...... ............................

MgO .................................

KsO...... ............................

Na30. ................................

H20..1... ............................

P205 . ................................

COs.. ................................

S03 ..................................

/ A.

5.27

1.07

.71

.32

50.36

.56

.10

.20

.78

.06

40.34

.07

99.84

B.

.32

 .17

.20

.02

55.25

.35

.

43.19

100. 10
CLARK E AND"! 

HILLBBBAND.J THE CARBONATE ROCKS. 265

MICHIGAN, WISCONSIN, MINNESOTA, CANADA.

Most of the rocks considered under this heading were described by 

Irving and Van Hise in Mon. XIX, pages 131 and 191. A few other analyses, also representing Van Hise's collections, are taken from the laboratory records. The Canadian rocks are from near the boundary line, 

and relate directly to others gathered upon the Minnesota side.

A. Dolomite. Near Sunday Lake, Gogebic district, Michigan. Analysis by W. F. Hillebrand, record No. 767.

B. Dolomite. Penokee region, Wisconsin, NW. £ sec. 22, T. 44 JST., 

B. 5 W. Analysis by Hillebrand, No. 768.

0. Limestone. Bed of Slate Creek, HUTOD Bay slate quarries, Michigan. Analysis by T. M. Chatard, record No. 894. From laboratory 

records; not in the monograph cited.

D. Limestone, east end of Ogiskemannissi Lake, Minnesota. Analysis by Chatard, record No. 899. Not in monograph.

Si02 .. ............

AlaOa. ............

FejOa ......:...,.

FeO.. ............

MnO .............

CaO .............

MgO .............

H2 0atl05° ......

H2O ign..........

P206 .............

CO...............

S03 ...........-l.

Cl ...............

A.

3.07

.09

.86

.15

29.72

19.95

| .30

45.31

Trace.

99.45

B.

.63

.03

.75

.08

30.94

20.68

| .27

46.27

99.65

C.

7.05

.48

1.33

Uiiclet.

.19

50. 08

.57

.25

.27

39.68

.21

100. 11

D.

41.99

1.24

.42

4 77

.26

16.85

8.41

.05

.1.02

.05

24.70

.32

100. 08
266 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

E. Iron carbonate, from SE. | sec. 20, T. 47 N., E. 43 W., Michigan.

F. Iron carbonate, south side of Sunday Lake, Michigan.

G. Iron carbonate, Palms mine, Gogebic district, Michigan.

Analyses E, F, G, by W. F. Hillebrand, record Nos. 769, 770, 771.

H. Iron carbonate, Miner and Wells Option, sec. 13, T. 47 N., E. 46 

W., Michigan. Analysis by T. M. Ohatard, record No. 893.

I. Iron carbonate, NW. £ sec. 18, T. 47 K., E. 45 W., Michigan. 

Analysis by Chatard, No. 895.

SiOs-. ..........

Ti03 ...........

A12O3 . ..........

Fe2 03 ..........

FeO. ...........

MnO. ..........

CaO.... ........

MgO. ..........

H2O at 105° ....

p o

C03 ............

S03 ..~ ........

01.... ..........

FeS2 ...........

.

E.

3.16

.08

.93

15.18

1.15

26. 65

11.01

} .54

- '.06

41.10

.34

100. 20

P.

28.86

.20

1.29

1.01

37.37

.97

.74

3.64

} .68

Trace.

25.21

99.97

G.

46.47

.10

.70

.86

28.57

.40

.49

2.30

| .60

Trace.

19.24

?

99.73

H. 

/ 

46.01

.12

.83

1.35

26.07

2.09

.63

2.86

j 1.71

.07

17.72

.15

99.61

I.

36.73

.19

.38

.98

34.81

.52

.48

2.74

.12 

1.40

.01

22.44

.16

100. 96
CLARKE AND"! 

HILLEBEAND.J THE CARBONATE ROCKS. 267

J. Iron carbonate, Penokee iron range, JST. E. £ sec. 6, T. 45, E. 2 E., 

Wisconsin.

K, L. Black, slaty, carbonaceous iron carbonates, Animikie formation, Kakabikka Falls, Kamiuistiquia River, Canada.

M. Iron carbonate, west end of Gunflint Lake, Minnesota.

Is". Iron carbonate, north side of Gunflint Lake, Minnesota.

O. Iron carbonate, north side of Gunflint Lake, Canada.

Analyses J, K, L, by E. B. Biggs, record Nos. 376, 377, 378. M, N, 

O, by T. M. Chatard, record Nos. 897, 898, 900.

SiOs ...........

TiOa ...........

ALA--. ........

Fe2 03 ..........

FeO.... ........

MnO ...........

CaO. ...........

MgO ...........

H2OatllO°.....

H20 at redness.. 

Pa06 . -- ........ ,

COS ............

SO. ............

c ..............

J.

15.62

4.27

8.14

32.85

5.06

.81

2.66

1 .68

30.32

100. 41

K.

37. 73

3.41

li.42

22.92

. .40

1.26

3.98

1 2.74

18.01

3.54

100. 41

L.

54.26

2.57

3.62

19.63

.19

1.07

2.93

1 1.20

14.93

.45

100. 85

M.

58.23

Trace?

.06

5.01

18 48

.25

.38

9.59

.07

2.01 

.03

5.22

.19

99.52

N.

46.46

Trace ?

.24

.64

26.34

.21

1.87

3.10

.07

1.15 

.13

19 <¥> 

.14

100.31

0.

23.90

.07

.44

10.72

.28

22.25

8.52

.99

32. 42

.17

99.76
268 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BOLL. 148.

P. Ferrodolomite, Marquette district, Michigan, Analysis by George 

Steiger, record No. 1473.

Q. Ferrodolomite, Marquette district, Michigan.

B. Portion of Q insoluble in hydrochloric acid.

S. Soluble portion of Q.

Analyses Q, E, S, by George Steiger, record No. 1442. These rocks 

are not in the monograph cited.

SiO2 .............

A12 03 . ............

Fe2 03 ............

FeO .............

MnO. ............

CaO .............

MgO. ............

H2OatlOO° ......

H2 0 above 100°...

P8 06 . ............

.CDs ..............

P.

42.37

1.09

31.41

.50

2.48

21.80

99.65

Q.

26.97

1.30

2.31

39. 77

.29

.66

1.94

OQ

.10

.51

.03

26.20

100. 17

E.

26.67

.12

.16

.10

27.05

S.

.30

1.18

2.15

39.77

.29

fifi

1.84

.09

.03

26.20

72.51
CLARKE AND") 

HILLEBKAND.J THE CARBONATE ROCKS. 

MONTANA.

269

Eocks collected by A. C. Peale. Analyses by Charles Catlett, record 

Nos. 890, 905.

A. North of East Gallatin Eiver.

B. West of North Boulder Eiver.

C, D. North of East Gallatin Eiver.

E. Base of Carboniferous, west side of Bridger Eange.

F. Middle Carboniferous, north of Gallatiu Eiver.

G, H. Upper Carboniferous, north of Gallatin Eiver.

Analyses all partial. A, B, C, D, H were published by Peale in 

Bull. 110, pp. 16, 28, and 40.

Insoluble.........

Fe203,Al2 03 ......

CaC03 ...........

MgC03 . ..........

Fe203, A120;1 ......

CaCO3 ...........

MgC03 . ..........

1

A.

.34

.22

54.54

43.63

99.73

E.

9.98

.38

88.50

.95

99.81

B.

1.78

.40

54.54

42.62

99.34

F.

5.99

.58

91.96

1.35

99.88

C.

23.50

2.50

67.85

6.18

100. 03

G.

50.74

.30

32.28

13.91

97.23

D.

35.26

1.92

59.11

1.96

98.25

H.

25.24

5.30

40.21

25.25

96.00
270 ANALYSES OF BOOKS AND ANALYTICAL METHODS. [BULL. 148.

COLORADO.

1. THE DENVER BASIN.

Eocks described by Emmons in Mon. XXVII. 

L. G. Baking, in the Denver laboratory. 

A. Upper Wyoming limestone, from Morrison. 

B. Niobrara dolomite.

Analyses made by

A1303 .. ...................... .........

Fe2 03 ................................

MnO.... .............................

CaO....... --..-..---.. ...............

MgO. ....... ........ .................

H2O. .................................

P205 ............ .....................

C02 ... ...............................

A.

5.32

.53

.38

.49

48.73' .

2.95

.11

.03

41. 71

100. 25

B.

12.01

.54

.11

.20

27.49

18.03

.61

.03

41.40

100. 42
CLARKE AND"] 

HILLKBKAND.J THE CARBONATE ROCKS. 

2. THE LEADVILLE DISTRICT.

 271

Eocks described by Emmons in Monograph XII. Analyses A, E, by 

W. F. Hillebrand; B, 0. D, by A. Guyard; all made in the Denver 

laboratory.

A. Silver Wave mine. Upper blue limestone.

B. Dugan quarry. Upper blue limestone.

C. Glass-Pendery mine. Upper blue limestone.

D. Montgomery quarry. Near base of blue limestone.

E. Carbonate Hill quarry. White limestone, upper part.

SiOa-... ........

A1203-.-. .......

Fe2 03 ..........

FeO. ...........

MnO. ..........

CaO...... ......

MgO ...........

EjO. ...........

NaaO. ..........

H,O. ...........

P20B ...........

COs,.... ........

S03 ............

Cl .............

FeSs ...........

Organic matter.

A.

.21

.27

.21

.24

Trace.

30.79

21.14

.03

.06

.22

Trace.

46. 84

.10

Trace.

.03

100. 14

B.

.70

.17

.11

.38

.05

30.43

20.78

.05

.09

.04

.12

46.93

.14

Trace.

.03

100. 02

C.

.27

.04

.22

.13

.20

29.97

21.52

.01

.02

.07

.03

47.39

.04

.02

99.93

D.

7.76

.11

.10

K7

.06

27.26

20.05

.02

.04

.05

.07

A3 7Q

.06

.07

100. 01

B.

11.84

1.66

1.51

.83

26.60

17.41

no

f)Q

.48

40.01

.05

100. 44
272 ' ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

3. F AIRPLAY, PARK COUNTY.

Analyses made by W. F. Hillebrand, in the Denver laboratory.

A. Serpentinous limestone, Buckskin Gulch.

B. Limestone, Fairplay.

C. Limestone, Mount Silverheels.

D. Dolomite-limestone, Mount Silverheels.

Analyses B, C, D, partial, with CO2 calculated to satisfy bases.

SiOa ...........

AlaOs--. ........

FesOa . .........

FeO... .........

MnO.. .........

CaO ...........

MgO.... .......

H2O.... ........

PB08 ...........

COa. .. .........

Cl .............

1

A.

17.64

.99

.62

.18

32.23

19.01

:07

3.72

.05

25.33

.08

> 99.92

B.

2.37

\ »

53.64

.73

.51

42.93

100. 37

C.

.51

\ -

55.50

.17

43.82

-100. 10

D.

1.98

1 AR 

\ ' 

30.19

20.47

46.52

99.62

4. PITKIN COUNTY.

Limestones and dolomites collected under the direction of S. F. 

Emmons. Analyses by George Steiger, record No. 1559. CO2 calculated to satisfy bases. Analyses partial only.

Insoluble. .... 

Fe203 ...... ..

FeO..........

CaO..........

MgO.:.......

. COa. .........

A.

.16

.22

.09

30.66

20.94

47.13

99.20

B.

.80 

1.63

.23

31.19

1Q fiQ

46.16

99.70

C.

1.02 

2.10

.06

33.74

16.76

44.94

98.62

D.

13.63 

1.88

.64

35.98

8.25

37.35

97.73

E.

1.42 

3.34

.42

31.61

18.06

44.70

99.55

F.

31.12 

.36

.19

37.28

.54

29.88

99.37

G.

7.78 

.88

.22

38.85

Q 97

41.47

99.17
CLABKE AND"! 

H1LLEBBDND.J THE CARBONATE ROCKS. 273

The following samples from Aspen were analyzed by L. G. Eakins. in 

the Denver laboratory. Partial analyses, CO2 calculated as before. 

H. Blue limestone. 

I. Limestone. 

J. Dolomite.

Fe20s .................. ....

CaO ............. ..........

MgO. ......................

C0a -... ....................

H.

.52

.88

31.16

20.64

47.19

100. 39

I.

.33

Trace.

55.81

.16 '

44.03

100. 33

J.

.84

1.31

30.46

20.90

46.92

100. 43

5. GLENWOOD SPRINGS, GARFIELD COUNTY.

Limestones and dolomites, collected under the direction of S. F. 

Einmons. Analyses, partial only, by George Steiger, record No. 1559. 

OO2 calculated to satisfy bases.

Insoluble. .... 

Fe.2 03 ........

FeO.... ......

CaO..........

MgO .........

COa .. ........

Insoluble ..... 

Fe2 03 ........ 

FeO..........

CaO..........

MgO.........

C02 . .........

A.

21.45 

.97 

.23 

40.64 

.73 

32.73

96. 75

H.

2.27

} .u

53.79 

.46 

42.76

99.42

B.

47.74 

.18 

.71 

15.87 

10.60 

24.13

99.23

c.

6.47 

.42 

.35 

46.65 

2.64 

39.55

96.08

I.

.22 

| Trace.

55.17 

.21 

43.58

99. 18

D.

3.71 

None. 

.55 

47.40 

4.49 

42.15

98.30

J.

.23 

1 .09

55.49 

.24 

43.87

99.92

E.

9.44 

.26 

.32 

39.56 

'8.56 

40.52

98.66

K.

.06 

None. 

None. 

55.81 

Trace. 

43.85

99.72

F.

17.82 

.74 

.57 

26.50 

14.86 

37.18

97.67

. L.

.22 

.10 

.10 

55.45 

.24 

43.84

99.95

G.

1.96 

.03 

.35 

32.14 

18.72 

45.85

99.05

M.

.11 

.03 

.07 

55.68 

Trace. 

43.75

99.64

Bull. 148 18
274 ANALYSES OF BOCKS AND ANALYTICAL METHODS. [BULL. 148.

6. TEN MILE DISTRICT, SUMMIT COUNTY.

Partial analysis, made in the Denver laboratory, by W.F. Hillebrand. 

CO2 calculated to satisfy bases. Manganese and iron present as carbonates, but Fe2O3 and A12O3 were not separated from them.

A. A. V. Fletcher shaft, Copper Mountain.

B. Pittston tunnel.

0. Pearl Hill, Middle Carboniferous.

D. Summit quarry.

E. Sheep Mountain. Dolomite.

F. Northwest corner of map. Oolitic limestone.

G. Pittston tunnel.

FeO, MnO.... 

CaO .........

MgO.. ........

o

C08 ... .-.-.-.

A.

2.69

.21 

54.23

.21

42.97

100. 31

B,

.62

.25 

55.24

.24

43.81

100. 16

C.

10.09

1.19 

28.01

18.33

42.63

100. 25

D.

1.75

.32 

53. 60

1.23

43.65

100. 55

E.

.78

1.50 

30.55

20.15

47.04

100. 02

F.

1.37

.20 

55.17

.28

43.76

100. 78

G.

7.91

.32 

50.83

.70

40.90

100.66 '

H. Blackbird tunnel, Tucker Mountain. Dolomite.

I. Summit King shaft, Summit City.

J. Ptarmigan Hill. Middle Carboniferous dolomite.

K. Hill north of Sugar Loaf.

L. Quarry on southeast side of Searl's Gulch.

M. Open cut below Sabbath Rest tunnel, Elk Mountain.

K Jacque Mountain. Triassic,

Insoluble .... 

FeO, MuO.... 

CaO .........

MgO.........

COs. ......

H.

2.68 

1.52 

31.60

18.27

45.75

99.82

I.

6.75 

3.08 

28.05

18.15

43. 88 

99.91

J.

.65 

1.67 

30.90

19.75

47.02

99.99

K.

4.42 

.10 

52.97

.40

42.12

100. 01

L.

.36 

.17 

55.58

.37

44.17

100. 65

M.

.82 

.07 

55.47

.22

43.86

100. 44

N. .

2.04 

.15 

54.62

.25

43.28

100. 34
CLARKE AND"! 

H1LLEBRAND.J ' THE CARBONATE ROCKS. 275

UTAH.

Marble from the Ontario mine, east end of the 1,000-foot level. 

Analysis made by L. G. Eakins in the Denver laboratory.

Insoluble .................................................. 9. 61

A13 0:, ...................................................... Trace.

CaO....................................................... 50.63

MgO....................................................... .09

C0a (calculated)........................................... 39.89

100.22

NEVADA AND CALIFORNIA.

A. Crystalline limestone, Eureka, Nevada. Analysis by E. A. 

Schneider, record No. 1279.

B. From base of the Hamburg limestone, Eureka district, Nevada. 

C. From summit of Hamburg limestone, Eureka.

D. Pogonip limestone, Eureka district, Silurian. Analyses B, C, t) 

made by W. F. Hillebrand in the Denver laboratory. Described by 

Hague in Mou. XX, pp. 40, 49. In D the CO2 was taken by difference.

E. Cretaceous limestone from Mount Diablo, California. Analysis 

made by W. H..Melville in the San Francisco laboratory, and published 

in Bull. Geol. Soc. Amer., vol. 2, p. 409. FeO and alkalies undetermined.

SiO2 -. ..........

AlaOs- ..........

Fe.2O;, ..........

FeO............

MnO ...........

Paf>

MgO ...........

H2 0 at 100° ....

H2O above 100..

P306 ... ........

CO2 . ...........

Cl .............

-

A.

.53

30.60

21.69

47. 13

99.95

B.

24.00

' .12

.12

41.97

.80

\ ,6

.07

32.62

.01

99.87

C.

3.94

. .64

.43

.20

.61

51.96

.52

| .37

.50

40.71

.03

.01

99.92

D.

9.34

.31

.29

50. 01

.54

\ .»

.24

39.11

Traces.

.03

100. 00

E.

21.19

.39

1.52

3.61

35.61

1.39

.76

2.33

2.55

26. 84

96.19
276 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

HAWAIIAN ISLANDS.

Coral and shell rocks, analyzed for N. S. Shaler by L. Gr. Eakins, 

record Nos. 886, 887, 889. Analyses only partial. 

A. Laie.

B, C. Kohuku Bluff. 

D. Kohuku coral-flat. 

E. Point near coral-flat. 

F. "Modern chalk," Oahu. 

G. Diamond Head. 

H. Under lava, Honolulu.

I. Old reef, Waialua. « 

J. Campbell's ranch, Waianea, Oahu. 

K. WailukuBay. 

L. Reef No. 3, Honolulu. 

M. Prison Knoll, Honolulu.

SiO2 .... ......

A1203 . ........

Fe203 ........

CaO.. ........

MgO... ......

C02 .... ......

H30.. ........

Si02 ... .......

A12 03 . ........ 

Fe203 ........

CaO..........

MgO.........

C02 . .........

H20.... ......

A.

.35

}. 

49.38 

1.74 

41.89 

4.74

98.29

B.

.19

| .52

49.34 

4.60 

44.33 

.40

99.38

H.

5.34 

j 5.11

42.24 

5.95 

38.71 

1.61

98.96

C.

,67 

| .73

51.09 

2.50 

43.64 

.79

99.42

I.

1.05 

| '1.26

51.07 

.11 

42.68 

1.33

97.50

D.

.25

}.«

53.34 

.67 

43.89 

.93

99.57

J.

.53 

] .62

50.69 

2.98 

43.96 

.46

99.24

E.

.26

}. 21

52.17 

1.51 

43.95

.70

98.80

K.

.45

} 1-82

50.54 

1.83 

42.80 

1.93

99.37

F.

33. 25 

19.53 

10.71 

11.37 

3.06 

11.09 

9.84

98. 85

L.

3.53 

| 2.26

46.52 

2.45 

40.59 

2.75

98.10

G.

2.97

j 2.88

44.82 

5.32 

40.81 

1.86

98.66

M.

.81 

j 1.19

52.67 

.42 

42.81 

1.24

99.14
CLARKE AND"! 

HILLEBBAND.J SLATES AND SHALES. 277

SLATES AND SHALES. 

VERMONT.

Samples A to I, inclusive, were collected by T. Nelson Dale, and 

analyzed by W. E. Hillebrand, record Nos. 1567, 1656. Eoofing slates 

of Cambrian age.

A. McCarty quarry, South Poultney.

B. Unfading green, Eureka quarry, Poultney. ,

C. Sea green, Griffith and Nathaniel quarry, South Poultney.

D. Sea green, Rising and Nelson's quarry, Pawlet.

E. Sea green, Browuell quarry, Pawlet.

F. Black, American Black Slate Company, Benson.

All six contain traces of lithia-, of sulphates, and of nickel or cobalt.

BiOs.... ........

Ti03 ...........

'AlaOs-.. ........

PesOs ..........

FeO. ...........

MnO. ..........

CaO.. ..........

BaO.... ........

MgO ...........

KaO. ....... ....

NasO.... .......

HaOatlOO0 ..... 

H20 above 100°. 

P206 ...........

COs ............

PeSa ...........

C ..............

A.

61.63

.68

16.33

4.10

2.71

.09

.50

.06

2.92

5.54

1.26

.31 

3.24 

.16

.41

.04

99.98

B.

59.27

.99

18.81

1.12-

6.58

.13

.42

.05

2.21

3.75

1 88

.32 

3.98 

.11

.21

.15

99.98

C. '

62.37

.74

15.43

1.34

5.34

.22

.77

-.07

3.14

4.20

1.14

.34 

3.71 

.06

.87

.06

99.80

D.

67.76

.71

14.12

.81

4.71"

.10

. .63

.04

2.38

3.52

1.39

.23 

2.98 

.07

.40

.22

100. 07

E.

59.84

.74

15.02

1.23

4.73

.34

2.20

.09

3.41

4.48

1.12

.41 

3.44 

.09

2.98

.05

Trace?

100. 17

F.

59.70

.79

- 16. 98

.52

4.88

.16

1.27

.08

3.23

3.77

1.35

.30 

3.82 

.16

1.40

1 18

.46

100. 05
278 ANALYSES OF KOCKS AND ANALYTICAL METHODS. [BULL. 148.

Or. Unfading green, Valley Slate Company's quarry, Poultney. 

H. Mottled, purple and green, Eureka quarry, Poultney. 

I. Purple 1 mile south of Hydeville, in Castleton. 

All three contain traces of lithia, nickel, and chlorine, and possibly 

of zirconia. In G and H, traces of strontia, but none in I.

SiOs...... ..................

TiO2 .......................

A12 03 . ......................

Fe2 03 ...... ................

FeO...... ..................

MnO. ......................

CaO. ...... ................

BaO. ....... ................

MgO .......................

KSO. .......................

NasO. .............. .........

H2OatllO° ................

H20 above 110°.... ...'......

P2 06 . .......... ............

cos ... ......................

. FeSs .......................

F ...... ....................

N, asNH3 ..................

G.

59.48

1.02

18.22

1.24

6.81

.07

- .56 '

.05

2.50

3.81

'1.55

.17

4.05

.10

.39

.13

.08

' .03

100. 26

H.

60.24

.92

18.46

2.56

5.18

.07

.33

.03

2.33

4.09

1.57

.18

3.81

.11

.08

.16

Undet.

.03

100. 15

I.

60.96

.86

16.15

5.16

2 <i4.

.07

.71

.04

3.06'

5.01

1.50

.17

3.08

.23

' .68

None.

Undet.

.01

100. 23
CLARKE AND"! 

HILLEBRAND.J SLATES AND SHALES. 279

J. Slate from Guilford, collected for the Educational Series of Eocks. 

Analysis by L. G. Eakins, record No. 1316.

K. Slate from the Lakeshore quarry, Hydeville. Analysis by 

Eakins, record No. 1159.

SiOa ...... ............................

TiOa .................................

A1203 . .................................

Fe2 03 ................................

FeO...... ............................

MnO ........... ....^. ................

CaO... ...............................

MgO. ................................

KaO.... ..............................

NasO..... ............................

HgO.. ................................ P,OB ......-.....................;....

S03 ... .

c ....................................

J.

60.72

22.59

6.03

Trace.

.41

2.05

3.69

.86

3.01

.13

.57

100. 06

K.

58.15

.93

18.93

2.91

5.64

.07

.60

2.70

Q Q9

1.17

4.56

.12

.16

99.86
280 ANALYSES OF ROCKS AND ANALYTICAL METHODS. fBULL.148.

NEW YORK.

Eoofing slates from Washington County, collected by T. Nelson Dale. 

Of Cambrian age.

A. Bed, three-fourths mile south of Hampton Village.

B. Empire Red Slate Company, near Granville.

C. National Eed Slate Company, Granville.

D. Green, three-fourtns mile northwest of Janesville.

Analyses by W. F. Hillebrand, record No. 1567. All contain traces 

of lithia, of sulphates, and of nickel or cobalt. No carbonaceous 

 matter is present.

Si03 .............

Ti02 .............

A1203 ...... .......

Fe3 03 ............

FeO...... ........

MnO...... .......

CaO .............

BaO .............

MgO. ............

KgO. .............

Na3O. ............

H2OatllO° ......

H2O above 110°... 

P206 .............

COs ..............

FeS2 .............

A.

67.61

.56

13.20

5.36

1.20

.10

.11

.04

3.20

4.45

.67

.45

2.97 

.05

.03

100.00

B!

67. 55

.58

12.59

5.61

1.24

.19

.26

.31

3.27

4.13

.61

.40

3.03 

.10

.11

.04

100.02

C.

56.49

.48

11.59

3.48

1.42

.30

5.11

.06

6.43

3.77

.52

.37

2.82 

.09

7.42

.03

100.38

D.

67.89

.49

11.03

1.47

3.81

.16

1.43

.04

4.57

2.82

.77

.36

3.21 

.10

1.89

.04

100.08
CLARKE AND"1 

HILLEBRAND.J SLATES AND SHALES. 281

E. Bed slate, from quarry 3 miles north of Eaceville. 

F. Green spot in E. 

G. Purple rim of green spot F.

Analyses by W. F. Hillebrand, record No. 1656. Contain traces of 

lithia and nickel. Fluorine not determined.

Si02 .. ......................

TiO2 .......................

AlsOa-...-.. .-.....-...- - 

Fe2 03 ......................

FeO.... ....................

MnO. ......................

faO

BaO .......................

MgO. ......................

K20 .......................

Na2O ......................

H2OatllO° ................

H20 above 110°. ............

P206 .......................

coa .... ....................

FeS2 .......................

E.

63.88

.47

9.77

3.86

1.44

.21

3.53

.05

5.37

3.45

.20

.27

2.48

.08

5.08

Trace.

100. 14

F.

65.44

.52

9.38

1.09

1.06

.32

4.53

.06

4.92

3.57

.22

.25

2.10

.08

6.55

.04

100. 13

G.

fid ^Q

.51

10.23

1 79

1 19

.26

4.07

.05

5.12

3.70

00

.28

2.29

' .08

5.84

Trace.

100. 23
282 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148. 

KENTUCKY, GEORGIA, ALABAMA.

A. Indurated Carboniferous shale, in contact with the peridotite dike 

of Elliott County, Ky. Described by Diller in Bull. 38. Analysis by 

T. M. Chatard, record No. 351.

B. Fragment of shale included in the Elliott County dike. Analysis 

by Chatard, record No. 353.

0. Bituminous shale, Dry Gap, Georgia. Analysis by L. G: Eakins, 

record No. 1316.

D. Middle Cambrian shale, Coosa Valley, near Blaine, Cherokee 

County, Ala. Analysis by H. N. Stokes, record No. 1549.

SiO2 .................

Ti02 .................

A12 03 ... ..............

Fe20:J ................

FeO... ...............

MnO. ................

CaO... ...............

BaO .................

SrO.... ..............

MgO... ..............

K2O... ...............

Na20. ..1. ............

Li20 .................

HS0 at 110°.. .........

H2O above 110°.......

P206 ..................

S03 ..................

S ....................

Cl ...................

C03 .... ..............

Carbonaceous matter .

Fixed carbon .........

Volatile hydrocarbons

Less O S...... ......

A.

41.32

.48

20.71

2.59

5.46

.17

q q-i

1 Q1

QQ

7 1Q

8

TQ

(\Q

KK

100. 03

B.

35.53

QK

Ifl 9Q

2.46

4.81

13

91 17

2 f)1

i fifl

9 KQ

1.40

9

nn

AQ

88

100. 26

C.

51.03

iq 4.7

8.06

78

1 1^

o -ic

.41

\ - 81

o-i

7.29

13.11

3.32

102. 90 

2.74

100. 16

D.

55.02

65

91 fi9

5.00

1.54

rPl*O fifk

i fin

.04

2

09

3.19

81

.03

2.44

5.65

.06

09

00

.32

100.54
CLAEKE AND! 

HILLEBKAND.J SLATES AND SHALES. 

OHIO.

283

Three samples of Utica shale, from New Vienna. Collected by 

Edward Orton. Partial analyses by F. W. Clarke and E. B. Eiggs, 

record No. 731.

Insoluble....... ............

CaO. .............i. .........

MgO. ......................

COS ........................

A.

60.17

17.11

1.25-

15.24

93. 77

B.

29.51

33.43

2.16

27.16

92.26

C.

25.80

35.27

1.32

27.40

89. 79

Iron and alumina are present in the soluble portion of these shales, 

the solvent being dilute hydrochloric acid.

WISCONSIN.

Slates of the Penokee-Gogebic series, collected by C. E. Van Hise. 

A and 0 are described in Mou. XIX, p. 306, as magnetitic clay-slates. 

Analyses by L. G. Eakins, record No. 392.

A. From sec. 6, T. 45 N., E. 2 E.

B. From sec. 1, T. 45 K, E. 1 E.

C. From sec. 4, T. 44 K, E. 2 W.

SiOa .. ......................

A1203 ..... ..................

Fe2O3 ......................

FeO...... ..................

MnO. ......................

CaO........................

MgO.......................

KsO... .....................

NaaO. ......................

Li2O .......................

HsO. .......................

p r\

A.

53.44

19.62

11.38

5.35

Trace.

.42

1.58

1.73

2.61

Trace.

4,07

100. 20

B.

59.73

22.78

.11

5.98

.09

.53

2.94

3.48

1.41

3.28.

100. 33

C. 

52.58

20.76

12.17

4.08

.21

.30

1.33

4.87

.37

Trace.

3.43

100. 10
284 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

COLORADO.

Shales from the Pueblo quadrangle, collected by G. K. Gilbert.

A, B. Near Nushbaum Spring.

C. Salt Creek.

D. Head of Rock Creek.

E. Near Rush Creek.

Analyses by George Steiger, record No. 1466.

SiO2 ...........

Ti02 ...........

AlaOs- .........

FeaOa ..........

CaO ...........

MgO.... .......

K2 0. ...........

Na2 0. ..........

H2OatlOO° .... 

H2O above 100°. 

P206 ...........

COZ .... ........

Organic matter.

A.

60.80

.47

15. 63 '

4.62

1.63

2.73

2.55

1.45

3.19 

4.16 

.10

2.87

100. 20

B.

K1 CO

.66

16.50

7 Qft

4.41

2.10

2.68

2.07

3.02 

6.00 

.22

3.19

.53

100. 97

 C.

60.60

.35

16.42

4. OK

1.61

1.43

2.98

.92

3.91 

. 5.72 

.31

.84

100. 04

D.

63.60

.66

16.74

4.63

.68

1 1Q

2.92

.29

2.88 

5.99 

.16

.46

100. 20

E.

45.89

KO

13.24

3.88-

-10 AQ

2.12

2

01

.47

1.38 

4.16 

.17

10.38

3.47

100. 08

Calcareous shales from Fairplay, Park County. Partial analyses, by 

W. F. Hillebrand, made in the Denver laboratory.

Fe2 03, A1203, etc ......................

FeO,MnO. ...........................

CaO .................................

MgO.................!...............

H2 0...... ............................

F.

68.72

2.10

9.06

5.72

1.01

13.41

100. 02

G.

35.14

2.10

19.34

12.55

.73

30.28

100. 14
CLARKE AND"! 

H1LLEBBAND.J SLATES AND SHALES. 285

CALIFORNIA.

Cretaceous shales from Mount Diablo. Described by Turner and 

Melville, Bull. Geol. Soc. Amer., vol. 3, pp. 383-414. Analyses by 

W. H. Melville, made in the laboratory at San Francisco, except F 

(record No. 1166), which was done in the Washington laboratory.

A. Brownish-black, resinous. From Bagley Canyon.

B. Slate-colored, soft, friable, little altered. From near Bagley 

Creek.

0. Same locality as B, less friable, but considerably altered.

D. Slate-colored, friable. From Arroyo del Cerro.

E. Very friable, same locality as D.

SiOs .........

A1203 - ..........

Fe2O3 ..........

FeO.... ........

NiO. ...........

MnO.... .......

CaO ...........

MgO.... .......

KaO. ...........

Na20. ..........

H2OatlOO° .... 

H2O above 100°. 

P206 ...........

COB ...... ......

S03 ............

A.

56.66

17.64

.49

5.22

.19

1.67

3.50

2.27

2.17

3.01 

5.92 

.15

.93

99.82

B.

53.65

17. 64

4.06

3.72

.01

2.27

5.15

2.22

2.53

3.95 

4.57 

.23

100. 00

C.

49 14

16.91

4.39

3.82

.22

3.28

5.43

1.53

4.67

3.39 

6.97 

.24

99.99

D.

25.05

8.28

.27

2.41

4.11

27.87

2.61

Undet.

Undet.

1.44 

2.86 

.08

24.20

99.18

E.

40.17

12.76

,2.10

3.56

.16

4.24

15.42

1.36

.57

9.19 

6.73 

.08

3.48

99.82
286 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

F. Neocomian shale, altered, light brown, friable. From near Arroyo 

del Cerro.

G. Calcareous shale near Arroyo del Cerro. Hard, compact, dark 

colored. Very much altered.

H. Red shale from the metamorphic area, head of Bagley Creek.

I. Silicified shale or phthanite. Same locality as H.

J. Clay-slate from near the head of Yaqui Gulch, in Mariposa County. 

Collected by H. W. Turner for the Educational Series of Eocks. Contains grains of quartz and feldspar, abundant carbonaceous particles, 

a chloritic substance (?), and a fibrous alteration of sillimanite (?). 

Analysis by George Steiger,. record No. 1643.-

Si02 ...........

Ti0.2 ...........

A1203 ... ........

Cr2O3 ..........

Fe2O3 ..........

FeO. ...........

MnO. ...... ....

CaO.. ..........

BaO. ...........

MgO ........... O

KaO. ...........

NasO. ..........

HsOatlOO0 ..... 

H2O above 100°.

P2o6 .. ..........

C02 ............

S03 ............

Cl.... ..........

F ..............

c ..............

F.

45.64

15.42

.12

 3.40

3.73

.33 .

8.11

4.62

1.86

3.13

| 8.74 

.27

4.59

99.96

G.

44. 56

3.12

1.27

5.21

Trace.

12.70

3.39

.88

3.09

1.41 

6.24 

.16

17.62

99.65

H.

69.98

11.69

6.23

1.08

.49

.38

1.29

3.72

.73

1.03 

2.92 

.05

99.59

I.

93.54

2.26

.48

.79

.23

.09

.66

' .51

.37

.21

.72

< 

99.86

J.

60.35

.75

17.62

5.64

2.20

None.

.45

.12

1.04

3.16

1.00

1.02 

4.36 

.17

.05

.01

Trace.

1.72

99.76
AND! 

H1LLEBKAND.J CLAY, SOILS, ETC. 287

CLAYS, SOILS, ETC.

MASSACHUSETTS.

Clays and soils from Marthas Vineyard, collected by 1ST. S. Shaler. 

See 7th Ann.,- p. 303. Analyses by F. W. Clarke, record Nos. 439, 440, 

441, 442,443, 444, 445, 446, 454, and 455. Partial analyses only.

A. Average sample of white clay, east end of Chilmark Cliffs.

B. Average sample of clays, Weyquosque series, Chilmark Cliffs.

C. Average sample of fine clay and soil, east end of Weyquosque 

Cliffs.

D. Sandy white clay, south end of Gay Head Cliffs.

E. Average sample of fine white clay, south end of Gay Head Cliffs.

SiOs...... ......

AlsOs-FesO-a- ....

CaO..... .......

MgO. ..........

K2O ...........

NasO. ..........

Ignition ........

P205 ...........

S03 . ...........

A.

82.95

13. 45

Trace.

3.47

99.87

B.

61.76

25.35

.51

1.95

3.01

1.83

5.76

100. 17

C.

 70.81

20.67

1.99

1.67

1.23

3.39

99.76

D.

56.19

30.65

None.

Trace.

10.79

2.45

100. 08

E.

73.46

19.06

None.

Trace.

.73

.70

6.36

100. 31

F. Average sample of clay, north end of Gay Head Cliffs. 

G. Average sample of southernmost red clays, Gay Head. 

H. Brown clay, south' of light-house, Gay Head Cliffs. 

I. Average sample of red clay from the greensand, north end of Gay 

Head. 

.J. Pyritiferous clay, central part of Gay Head section.

SiOs... .........

A12O3, Fe203 .-.. 

CaO... .........

MgO...........

K8O. ........ ...

Na,3O. ..........

P206 . ..........

F.

49.19

39.77

11.47

N"OUG

100. 43

G.

57.50

31.21 

19

.20

-i .40

9.83

99.33

H.

56.62

31.24

1.97

2.76

.40

7 £>7

100. 56

I.

55.93

33.51

.19

Undet.

Undet.

9.98

99.61

J.

72.74

21.46

5.69

99.89
288 ANALYSES .OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

NEW YORK, PENNSYLVANIA,- DELAWARE.

A. Clay from near Bichfield Springs, N. T. 

Charles Catlett, record No. 946.

B, C. Two clays from Northumberland County, Pa. 

Charles Catlett, record No. 952.

D. Kaolin, Hockessin, Del.

E. Portion of D insoluble in sulphuric acid.

F. Portion of D soluble in sulphuric acid.

Analyses D, E, F by George Steiger, record No. 1626.

Partial analysis by 

Analyses by

SiOs......'......

Ti02 ...........

A1203 ..........

Fe2O3 ..........

CaO ...........

MgO...........

K2O.. ..........

Na20... ........

H2Oat 100° ....

H2O above 100°. 

P206 ...........

A.

49.65

| 23.82

6.48

Undet.

Undet.

| 16.18

96.13

B.

65.97

20.37

2.75

.64

.52

3.32

.05

j 6.28

99. 90

C.

59.16

18.68

10.32

.52

.67

3.35

.11

| 6.87

99.68

D.

48.73

.17

37.02

. .79

.16

.11

.41

.04

.52

12.83 

.03

100. 81*

E.

29.55

.11

18.44

.27

.02

Trace.

.41

.02

6.84 

Undet.

55.66

F.

19.18

.06

18.58

.52

.14

.11

None.

.0*

5.99 

Undet.

44.60
CLAEKE AND") 

HIL1.EUKAND.J CLAY, SOILS, ETC. 289

VIRGINIA, NORTH CAROLINA.

A. Residual clay from decay of Trenton limestone, Lexington, Va. 

Described by Eussell iu Bull. 52. Analysis by B. B. Biggs, record No. 

373. See also analysis of the limestone.

B. Residual clay from limestone, Staunton, fVa.

0. Portion of B soluble in weak hydrochloric acid.

D. Insoluble portion of B. Analyses B, C, D, by George Steiger, 

record No. 1630. See also analysis of limestone.

E. Decomposed clolerite, from near Wadesboro, N. C. Described 

by Eussell in Bull. 52. Analysis by T. M. Chatard, record No. 327.

F. Eesidual clay from decay of chloritic schist. From Gary, 8 miles 

west of Raleigh, N. C. Analysis by E. B. Riggs, record No. 364. Described by Eussell in Bull. 52.

SiO2 ..... ......

TiO, ...........

AloO,.. .........

Cr,03 .... ......

Fe=,'>3 ..........

FeO.... ........

MnO. ..........

CaO.. ..........

MgO. ..........

KaO.... ........

NasO. ..........

HoOatllO0 .....

IUO above 110°. 

p n

Of),

A.

43. 07

25.07

15.16

.63

.03

2.50

1.20

1 12.98

100. 64

B.

55.90

.20

19.92

7.30

.39

.50

1.18

4 79

.23

2.54

6.52 

.10

.38

99.95

C.

3.09.

.04

3.96

6.25

.30

.30

.43

.28

.20

2. 1C 

.04

.38

17.37 .

D.

52.81

.16

15.96

1.05

.09

.20

.75

4, 51

.03

4.42 

.06 '

80.04

E.

39.55

.64

28.76

16.80

.37

'.59

Undet.

Undet.

1 13.26 

.10

100. 07

F.

54.54

26.43

Q 04.

] 9. 87

99.88

Bull. 148 39
290 ANALYSES OF BOOKS AND ANALYTICAL METHODS. [BULL. 148. 

SOUTH CAROLINA, GEORGIA.

A, B, C. Clays from near Augusta, Ga. Partial analyses by George 

Steiger, record No. 1395. 

D. Kaolin from Aiken, S. C. Analysis by Steiger, No. 1472.

SiOs. .............

TiO* .............

 Al*03 . ............

Fej03 ............

CaO... ...........

MgO.............

HSO at 100° ......

HiOat200° ......

HS0 at 300° ......

H2O, ignition .... . 

P205 ..:..........

A.

60.24

1 26.72

.88

Undet.

6.28

94.12

B.

61.36

1 29.04

.76

Undet.

. 7.46

98.62

C.

60.70

1 29.24

/

. .68

Undet.

6.74

97. 36 .

D.

44.94

.65

39.18

.52

.47

.'20

.27

13, 38 

.12

99.73

FLORIDA.

A. Hammock clay, Melborne Creek. Collected by N. S. Shaler. Partial analysis by L. G. Eakins, record No. 881.

B. Clay from Tampa.

C. Clay from Lakeland.

B, C, collected by W. H. Dall. Analyses by L. G. Eakins, record 

No. 1255, partial.

Si02 ........................

A12 03, Fe2O3 ................

CaO ........................

MgO .......................

o

HoO.... ....................

C03 .... ....................'

A.

38.04

27.19

'l0.73

.46

1 23.61

100. 03

B.

70.78

11.33

'2.18

14.55

98.84

C.

80.39

15.03

1.22

4.34

100. 98
CLAEKE AND"! 

H1LLEBRAND.J CLAY, SOILS, ETC. 291

Clays collected by G. H. Eldridge.

D, E. From the Saiidlin place, 2 miles southeast of Marion, Hamilton County.

F. From Bichmond's, 6 miles south of Leesburg, Lake County.

G-, H. From Bartow Junction.

Analyses D, E, F by H. N. Stokes, record No. 1493 ; G, H, by George 

Steiger, No. 1545.

SiOa. ...........

AbOa.. .........

Fe,O3 ..........

FeO...... ......

CaO... .........

MgO ...........

Hit) at 100° .... 

H3 0 above 100°. 

PS06 ...........

C0a . ...........

D.

15.68

.61

.45

26.11

17.28

} 1.97

37.90

100. 00

E.

78. 23

7.30

1.85

1.60

2.11

| *8.48

99. 57

F.

84. 41

11.02

.20

1 *4. 25

99.88

G.

70 qq

10.82

3.25

.25

.23

.07

.90 

4, 09

99. 87

H.

79. 48

12. 14

2.64

OQ

31

.07

.86 

4. 73

\i /in ^

100. 32

" Includes a little C02 .
292 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

ALABAMA, MISSISSIPPI.

A. Kaolin, Greenville, Ala. Contains about 40 per cent of kaolin, 

with fragments of quartz, feldspar, and mica. Analysis by T. M. 

Chatard, record No. 1148.

B. Eesidual clay from decay of Knox dolomite, Morrisville, Ala. 

Described by Eussell in Bull. 52. Analysis by W. F. Hillebrand, 

record No. 797. See also analysis of the dolomite.

C. Loess from Yicksburg, Miss. Described by Chamberlin and 

Salisbury, 6th Ann., p. 282. Analysis by E. B. Eiggs, record No. 294.

SL02 . .......................

TiOa ...... ..................

Ala03 . ......................

Ye.203 ......................

FeO...... ..................

MnO .......................

CaO...... ..................

MgO .......................

KaO.... ....................

Na20. ......................

H30 at 110° ................

HaO,ign.... ................

PgOfi.... ....................

COa . ....................

S03 ........................

Cl...... ....................

A.

69.84

19.91

.90

Trace.

.07

.28

2.14

.21

.06

6.72

100. 13

B.

55.42

22.17

8.30

.15

1.45

2.32

.17

2.10

7.76

99.84

C.

60. 69'

.52

7.95

2.61

.67

.12

8.96

4.56

1.08

1.17

1.14

.13

9.63

.19

.12

.08

99.62
CT.ARKE AND") 

HILLEBKAND.J CLAY, SOILS, ETC. 

ILLINOIS, IOWA, MINNESOTA.

293

A, B. Clays from Henry County, 111. Analyses by T. M. Chatard, 

record' No. 144.

C. Loess; a stratum overlying residuary clay, 350 feet above the Mississippi Elver, near Galena, 111. Described by Chamberlin and Salisbury, 6th Ann., p. 282. Analysis by E. B. Eiggs, record No. 293. 

Dried at 100°.

D. Loess, 300 feet above the Mississippi, 3£ miles northwest of Dubuque, Iowa. Described by Chamberlin arid Salisbury (I. c.), and analyzed by Eiggs, No. 292. Dried at 100°.

B. Tallow clay, from a lead mine at Lansing, Iowa. Collected by 

W. P. Jenney. Analysis by H. N. Stokes, record No. 1337. Dried at 

100°. Partial analysis.

F. Greenish-gray clay, New Ulm, Minn. Analysis by T. M. Chatard,

record No, 825,

&iOs . ...........

Ti03 ...........

AlaOs........... 

Fe.-.0:) ..........

FeO ............

MnO. ..........

ZnO.. ..........

PbO ...........

CaO. ...........

BaO.. ..........

MgO ...........

ICsO. ...........

Na2 0. ...... ....

HsO. ...........

P,06 :..........

CO.............

S03 ............

01.... ..........

A.

46. 12

70

15. 24 

4 41

.28

8.63

3.63

3.79

1.54

15.57

.08

100. 08

B.

42. 58

.64

12.16 

3.90

.09

11 33

4.32

3.88

1 Qfi

18.64

.10

99.60

C.

64.61

.40

10.64 

2.61

.51

.05

5.41

3.69

2.06 '

1 3^

2.05

.06

6.31

13

.11

.07

100. 06

D.

72.68

.72

12. 03 

3.53

.96

.06

1.59

 1. 11

2.13

1.68

2.50

.23

.39

no

K1

.01

100. 22

E. 

52.08

23. 11 

9. 34

1.04

2.12

Undet.

Undefc.

9.80

97.49

P.

61.32

.66

12. 27 

3.62

4,18

.27

.99

. .05

1.76

3. 59

42

10. 73

.27

iq

100. 32
294 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

WISCONSIN.

Clays, etc., described by Chamberlin and Salisbury in 6th Ann., pp. 

250 and 282. Analyses by E. B. Eiggs, record Nos. 259,260,261,262, 

290,295. Dried at 100°.

A. Eesiduary clay from Dodgeville, 4^ feet below surface.

B. The same, 8J feet below surface.

C. Eesiduary clay from near Cobb, 4£ feet below surface.

D. Same as C, 3£ feet below surface.

E. Eed, putty-like clay, containing pebbles, Milwaukee.

F. Eed pebble clay, Milwaukee.

SiOs . ...... ....

Ti02 ...........

AlsOa. ..........

FeaO:, ..........

FeO. .........'..

MnO ...........

CaO..... .......

MgO ...........

KoO. ...........

NaaO. ..........

HaO. ...... '...-.

PaOr,. ...... ....

coa . . .:........

S03 ............

Cl .............

A.

71.13

.45

12.50

5.52

.45

.04

.85

.38

1.61

2.19

4.63

.02

.43

.19

100. 39

B.

49.59

.28

18.64

17.19

.27

.01

.93

.73

.93

.80

10.46

.03

.30

.34

100. 50

C.

49.13

.13

20.08

11.04

.93

.06

1.22

1.92

1.60

1.33

11.72

.04

.39

1.09

100. 68

D.

53.09

.16

21.43

8.53

.86

.03

.95

1.43

.83

1.45

10.79

.03

.29

.22

100. 09

E.

40.22

.35

8.47

2.83

.48

Trace.

15. 65

7.80

2.36

.84

1.95

.05

18.76

.32

.13

.06

100. 27

F.

48.81

.45

7.54

2.53

.65

.03

11.83

7.05

2.60

.92

2.02

.13

15.47

.38

.05

.04

100. 50
CLABKE ANDT 

HILLEBRAND.J CLAY, SOILS, ETC. 295

MISSOURI, ARKANSAS.

A. Typical loess, Kansas City, Mb. Dried at 100°. Described by 

Chainberlin and Salisbury, 6th Ann., p. 282. Analysis by K. B. Kiggs, 

record No. 291.

B, C; D, E.' Tallow clays, Joplin, Mo. Collected by W. P. Jenney. 

Analyses by T. M. Chatard, record No. 1210.

F. Tallow clay, Aurora, Mo. Collected by Jenney. Analysis by Chatard, No. 1210. In analyses B, C, D, E, F the percentages of bases 

relate to the portion soluble in hydrochloric acid. Analyses only 

partial.

Si02 ...........

TiO., ...........

A1303 . ..........

Fe20a ..........

FeO.. ..........

MnO ...........

ZnO...... ......

CaO... .........

MgO ...........

K2 0 ...........

'NasO... ........

H,0,. ..........

P206 . ..........

CO.............

S03 ............

Cl .............

A.

74.46

.14

12.26

3.25

.12

.02

1.69

1.12

1.83

1.43

2.70

.09

.49

.12

.06

.05

99.83

B.

40.64

5.72

1.30

32. 46

1.80

.27

17.19

99.38

C.

43.07

7.60

1.12

29.43

1.70

.32

16. 74

99.98

D.

39.34 '

6.17

1.16

34. 28

2.13

.27

17.63

100. 98

E.

39.62

6.45

1.53

33. 55

1.77

.30

16.95

100. 17

F.

34.04

10.01

3.62

33. 49

2.09

.25

16.96

100. 46
296 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. 148.

The following partial analyses by H. ~N. Stokes, record No. 1260, all 

relate to tallow clays collected by W. P. Jenney. The same remarks 

apply as to B, C, D, E, F.

G. Cave Springs mine, Jasper County, Mo.

H. Great Western mine, Granby, Mo.

I, J, K. Woodcock mine, Granby.

L. Coon Hollow, Boone County, Ark.

Material dried at 103°.

Insoluble. ......

Soluble SiO,....

A12 03 . ..........

FeaOs .--.-...-.

ZnO ...........

CaO... .........

MgO...... .....

Ignitiou ........

G. -

34.89

16.75

- 7.38

10.34

14.35

1.55

.35

10.37

95.98

H.

11. 25

32.89

10.78

3.89

29.54

2.65

.90

8.22

100. 12

I.

2.41

36.71

8.21

. 2.75

38.59

2.77

.78

7.99 .

100. 21

J. .

16.17

28.62

8.93

5.98

26.23

2.01

.46

9.19

, 97.59

K.

3.85

37. 08

6.46

3.49

38.90

2.56

.42

7.52

100. 28

L.

18.18

29.02

6.34

4.40

30.50

1.91

.75

8.36

99. 46
CLABKE AND") 

HlLbEURAND.J CLAY, SOILS, ETC. 297

COLORADO.

A. Loess from Denver.

B. Loess from Highland.

C. Concretion in loess from Wray.

A, B, C collected by S. F. Emmons, analyses by L. G. Eakins, record 

No. 1066.

D. Clay from Davis ranch, Pueblo quadrangle.

E. From head of Eock Creek, Pueblo quadrangle.

D and E collected by G. K. Gilbert, analyses by George Steiger, 

record No. 1457.

.

SiOa.. ..........

Ti02 ...........

Al,0... .........

Fe.2 03 ......--.-

FeO...... ......

MnO ...........

CaO. ...........

MgO. ..........

KaO. ...........

NasO.. .........

H30atl00c .... 

H2 0 above 100°. 

P20fi ...........

C0«...... ......

Organic matter.

A.

69. 27

13.51

3.74

1.02

2.29

1.09

3.14

1.70

| 4.19 

.45

100. 40

B.

60. 97

15.67

5.22

.35

2.77'

1.60

2.28

.97

| 9.83 

'.19

.31

. 100.16

C.

70.63

10.43

2.58

.48

4.64

1.13

2.'50

1.29

| 3.77 

.20

2.59

100.24

D.

63. 52

.68

24.72

.43

.30

.13

1.58 

8. 41

.40

100. 17

E.

76.56

.60

8.30

.38

.12

.24

1.26 

4.40 

.06

8.31

100. 23
298 ANALYSES OF ROCKS AND ANALYTICAL METHODS. [BULL. us.

F. From Red Creek Canyon, south part Colorado Springs quadrangle.

G. From 2 miles southeast of F.

H. From near Canyon.

I. Overlying H. '

Collected as probable fire clays by G. K. Gilbert, analyses by George 

Steiger, record No. 1578. Fe^O3 represents total iron. A12O3 includes 

TiO2 . In I, the ignition includes some CO2 , which is absent from the 

others.

SiOs ... ...........

Ala03 .... .........

Fea03 ............

CaO.... ..........

MgO ............. O

K3O ..... ........

Na2 0. ............

PaO fi . ............

Ignition ..........

r.

85.09

6.98

1.10

.21

.27

.13

.06

6.37

100. 21

G.

86.79

8.29

.75

.34

.13

.25

.05

3.78

100.38

H.

57.98

27.51

. 1.68

.42

.32

.56

. .03

.06

11.80

100. 36

I. 

cq 04.

14.51

3.78

1.24

.73

.48

.08

.07

10.50

100. 43

J to K. Supposed fire-clays collected in the area of the Apishapa 

sheet, by G. K. Gilbert. Analyses, partial, by H. E". Stokes, record 

No. 1503. Titanium present, alkalies undetermined. Analyses made 

on ignited material, reckoned as 100. The loss on ignition is separately 

stated below each analysis.

Si03 ...... ......

A1203 ..........

Fe2 03 ..........

CaO............

. xMgO...........

SiOa.. ..........

Al2O:i . ..........

FeoOn ..........

CaO............

MgO ...........

J.

86.58

12.72

.45

.11

.11

98.97

4.75

K.

78.07

20.22

.89

.26

99.44 

7.51

0.

85.98

13.67

.41

.21

100. 27 

5.07

L.

76.96

20.77

1.11

.71

.32

99.87 

7.98

P.

85.25

11.45

2.24.

.26

.21

99.41 

4.81

M.

61.98

37.51

.45

1Q

09

100. 22 

12.51

Q-

^4- Q3

43.65

.69

.64

.05

99.96 

16.80

N.

93.11

5.56

1.15

.32

.10

100. 24 

4.45

K.

58. 56

39.17

.55

1.08.

.45

99.81 

19.58
CLARKE AND"! 

HILLBBBAND.J CLAY, SOILS, ETC. 299

S. Loess-like alluvium, Golden, Jefferson County. 

T. Fire-clay, Golden, Jefferson County.

Analyses S and T made by W. E. Hillebrand in the Denver laboratory.

SiOs ...... ............................

AlaOs..... .........'...................

Fea03 .. ...............................

CaO..................................

MgO .................................

K2O ..................................

NOaO.. ......... ......................

PA.... ............ ..................

S.

72.31

12.66

4.67

1.15

.94

3.75

2.47

1.80

.23

no no *?!/ t/O

T.

50.35

34.44

.75

.48.

.10

13.88

100. 00

WYOMING, UTAH, NEW MEXICO.

A. Loess from Cheyenne, Wyo. Analysis by L. G. Bakins, record 

No. 1066.

B. Adobe soil, Salt Lake City, Utah. 

C. Adobe soil, Santa Fe, N. Mex. 

D. Adobe soil, Fort Wingate, N. Mex. 

Analyses B, 0, D by Eakins, Nos. 981, 996.

-

SiOa-... ..........

AlsOa---... .......

Fe.2O3 ............

FeO...... ........

MnO...... .......

CaO .............

MgO.... .........

KaO.. ............

Na.2O. ............

H2 0. .............

P2 0fi .............

COa.... ....:.....

S03 ..............

01 ...............

A.

67.10

10.26

2.52

.31

5.88

1.24

2.68

1.42

5.09

.11

3.67

100. 28

JB. '

19.24

3.26

1.09

Trace.

38.94

2.75

Trace.

Trace.

1.67

.23

29.57

.53

.11

2.96

100. 35

C.

66.69

14. 16

4.38

.09

2.49

1.28

1.21

.67

4.94

.29

.77

.41

.34

2.00

99.72

D.

26.67

.91

.64

36.40

.51

Trace.

- 2.26

.75'

25.84

.82

.07

5.10

99.97
300 ANALYSES OP ROCKS AND ANALYTICAL METHODS. [BULL. 148.

NEVADA.

A. Grayish clay from Upper Lahontan lake beds, Humboldt Eiver 

bridge, Mill City.

JB. Grayish clay, same locality, Lower Lahontan beds. Analyses by 

T. M. Chatard, record Nos. 32, 33.

0. Adobe soil, Humboldt. Analysis by L. G.Eakins, record No.981.

D. Halloysite, pale greenish, Lucia mining district, Elko County. 

Analysis by George Steiger, record No. 1472.

SiOa...... ........

AlsOs. .........

Fe2 03 ............

FeO. ...... ...'....

MnO .............

CuO .............

CaO. .............

MgO. ............

KaO.. ............

Na-,0 ............

H2 0 at 100°. ......

H2 0at200° ......

H2O at 300° ......

H20, ignition ..... 

. PaOB .. ............

CO* ..............

S03 ..............

Cl. ...............

Organic matter... O

A.

56.30

16.52

5.08

5.45

2.64

2.17

2.60

9.78

100. 54

B.

50.70

T 19.01

10.26

3.19

2.16

1.91

13.03

100. 26

C.

44.64

13.19

5.12

.13

13.91

2.96

1.71

.59

3.89

.94

8.55

.64

.14

3.43

99.84

D.

42.11

33.83

.04

.28

2; 83

.33

.30

6.54

1.07

1.26

12.04 

Trace.

100. 63
CLARKK AND"] 

HILLEBUAND.J CLAY, SOILS, ETC. 301

CALIFORNIA, WASHINGTON, HAWAIIAN ISLANDS.

A. Sandy clay, Owens Lake, California.

B. Blue clay, Owens Lake, California. Analyses by T. M. Cbatard, 

record No. 551.

C. Clay from foot of Eickey Hill, Kittle Falls, Stevens County, 

Wash. Analysis by W. F. Hillebrand, record No. 1428.

LX Lava soil, Diamond Head, Hawaiian Islands. Analysis by L. G. 

Eakins, record No. 888.

- SiOs ... ...........

Ti03 .............

A12 03 . ............

Fe2 03 ............

1<VO

MnO. ............

CaO...... ........

.SrO.... ..........

MgO. ............

KsO...... ........

NasO. .............

H2OatllO° ......

HaOatreduess.... 

P2 05 .............

C03 .... ..........

SOa ...../.. ......

CL. ..............

A.

53.24

.25

10.84

2.59

.77

.10

9.18

5.82

2.64

2.06

1.41

2.73

8.75

.08

.05

100. 51

B.

54.92

.30

11. 25

2.77

.94

.08

8.76

4.91

2.77

2.10

2.05

2.40

7.24

Trace.

Trace.

100. 49

C.

62.74

16.45

2.62

1 Q1

3.68

2.41

3 CO

3.05

j 2.69

.65

99.73

D.

32.88

12.02

11.52

12.20

11.70

Undet.

Uridet.

| 5.30

.24

11.41

Q1

98.18

INDEX TO ROCKS

A. Pago. 

Absarokite..................... 125,129

Acmite-tracliyte.................. 145

Actinolite-magnetite-schist....... 113

Adobe soil....................... 299, 300

Albite ........................ 65,67,78

Amphibolite .......... 71,75,76,211,228

' Analcite ....................... 155,164

Anal cite-basalt .................. 164

Andalusite-schist ................ 221

Aiidesite ........................ 91, 97,

119,120,121,133,134,135,140,152,

159,163,165,171,188,189,190,195,

196,197,202, 207, 217, 223, 232, 233

Andesite-basalt .................. 190

Anorthoclaso................ 78,107,145

Aplite ................. 124,150,206,219

Aporliyolite...................... 81

Argillite ....................... 209,210

Arkose-gneiss.................... 77

Asperite ......................... 223

Augite..................... 158,164,185

Augite-andesite ............ 119,123,159

Augite-andesite-porphyry ...... 119,123

Augite-bromite-aiidesite ......... 232

Augite-diorite.....'............. 165,180

Aiigitc-granite................... 212

Augite-mica-syenite.............. 158

Angite-porphyrite.............. 138,183

Augite-syenite ................... 217

Augite-vogesite.................. 151

B.

Banakite. ...................... 127,128

Basalt........... 80,97,122,135,136,137,

139,151,153,158,162,163,164,

184,185,189,190,198,199,200,

203,205, 215, 218, 223, 230,231

Biotite-diorite.................... 85

Biotite-gneiss .................... 102

Biotite-granite ........ 74, 86,87, 206,214

Biotite-porphyrite................ 173

Boltonite ........................ 77

Bronzite ......................... 84

C. Page. 

Camptonite .............. 67,70,136,211

Cancriiiite ....................... 66

Chert.......................... 252,253

Chiastolite-schist................. 221

Clay............................. 287,

288,289,290,291,292,293,294,

295, 296, 297, 298, 299, 300, 301 

Coquina .......................... 259

Coral ............................ 260

Coral rock ................. 259,260,276

Corclierite-hornfels............... 70

Cortlandtite ..................... 84

D. 

Dacifce ........................ 116,121,

132,167,188,191,193,194 

Dacite-porphyry.................. 191

Diabase ................. 70,90,103,104,

143,159, 205, 208,220,224 

Diabaee-diorite. .................. 224

Diabase-porphyri te............. 143, 228

Diabase-porphyry................ 207

Diallage ....................... 104,106

Dial]age gabbro.---.............. Ill

Diopside......................... 84

Diorite........... 69, 70, 85,117,118,119,

124,143,144,148,151,165,176,

177,178,180,181,191, 204,205,

206, 214,215,218, 220, 232, 233

Diorite-porphyrite................ 143

Diorite-porphyry....... 148,176,181, 214

Dolerite ......;............ 158,203,289

Dolomite.................. .... 254,255,

. 258, 264,265,270,272,273,274 

Dtinite.--.-...................... 91

E. 

Elceolite ............. I........... 66,67

ELwolite-syenite....... 65, 67, 80,145,162

Eiistatite ....................... 72,241

Enstatite-diabase-porphyry........ . 159

F. 

Feldspar ....... 65, 67, 78, 82, 89,103,104,

105,107,112,145,173,174,185,230 

303
304 INDEX TO ROCKS.

Page. 

Feldspar-porphyry ............... 151

Ferrodolomite.................... 268

Fulgurite ........................ 230

G.

Gabbro.......... 82, 85,100,104,106, 111,

112,113,122,123,144, 212, 225 

Gabbro-diorite .......... 85,101,113,123

Gabbro-porpliyry..... ...... ...... 122

Garnet........................... 92

Gentliite ......................... 231

Glaucophaiie-schist............. 222,224

Gneiss .. 77, 87,88, 91, 99,102,160, 214, 215 

Granite ............. 68, 71, 74, 86, 87,92,

95,107,110,142,150,159,160,

179,201, 206, 212, 213, 214, 219

Granite-porphyry ............... 69,

142,146,147,176, 219 

Granite-ay en ite-porphyry....... 148,155

Granitite"........... 68,142,159,160, 213

Granodiorite .................. 201, 204,

208,209, 210, 211,212, 213 

Granulite ................!..... 206,219

Gray wacke ...................... 105

Greenstone............ ...... 98,101,102

Griinerite-maguetite-schist ....... 98

H. 

Halloysite...... .................. 300

Hornblende...................... 154

Horublende-andesite ............. 120,

134,190,195, 202, 233 

Hornblende-basalt ............... 200

Hornbleude-diorite.......... I.... 85

Hornblende-granite ......... .... 71,142

Hornblende-mica-andesite....... 121,134

Hornblende-rnica-andesite-porphyry......................... 124,133

Hornblende-mica-porphyrite.... 119,178

Hornbleude-picrite............. 140,146

Hornbleude-porphyrite........... 119,

173,180,183,187,208 

Hornblende-pyroxene-andesite.... 120,

202, 207 

Hornfels ................... ...... 70,221

Hornstone........................ 144

Hydrouephelite .................. 66

Hypersthene ................... Ill, 171

Hypersthene-andesite.......... 140,171,

188,190,196,197, 202, 207 

Hypersthene-basalt ...........;.. 230

Hypersthene-gabbro ............. 85, 111

I. 

Ilmenite ......................... 92

Iron carbonate ............. 266,267,268

J.

Jasperite

Page. 

253

K.

Kaolin..................... 288,290,291

Keratophyr ...................... 78

Kersantite....................... 136

L. 

Labradorite -porphyrite .......... 97

Lamprophyro ........ T ..... 138,139,182

Lava soil.......................... 301

Lepidornelaue.................... . 66

Leucite-absarokite............... 125

Leucite-banakite..............:.. 128

Leucite-basalt ................... 153

Leucite-nionchiquite ............. 153

Leucite-shoshonite ..... I......... 126

Leucite-syeuite ................ 153,154

Leucite-trachyte ....... .... ...... 115 ,

Leucitite ...................... 116,157

Lherzolite ....................... 83

Limburgite ...................... 79

Limestone ...................... 254-275

Loess .............. 292,293,295,297, 299

M. 

Magnetite...................... 105,113

Marble............. 254, 255, 257, 258, 275

Melaphyr ........................ 215

Meteorites ...................... 234-246

Mica-andesite ................... 97,185

Mica-basalt...................... 187

Mica-dacite ...................... 167

Mica-dacite-porphyry ............ 133

Mica-diorite...................... 85

Mica-diorite-porphyry -........... 102

Mica-gabbro..................... 122

Mica-gabbro-porphyry............ 122

Mica-leucitite.................... 116

Mica-peridotite .................. 94

Mica-schist..................... 113, 221

Microcline ....................... 89

Micropeginatite.................. 219

Microperthite-hornfels ........... 70

Minette ......................... 80,149

Missourite ... ^ .................... 154

Monchiquite ........... 144,149,151,153

Monzonite ............. .123,149,154,156

Muscovite........................ 90

N. 

Nepheline........................ 66,67

Nepheline-basalt ................. 162

Nepheline-syenite ..... 65, 67,80,145,162

Nevadite..................... .... 174 

Novaculite....................... 99
INDEX TO ROCKS. 305

0. Page.

Obsidian........... 130,186,223,228,229

Olivine i................ 92,111,231,238

Olivine-basalt.................... 203

Olivine-diabase .................. 104

OliAdne-gabbro........... 85,100, 111, 144

Orthoclase .................: 07,173,174

Orthoclase-gabbro-diorite ........ 123

Ottrelite........--..---.....-.-.. 90

Ottrelite-phyllite ................ 90

Ouacbitite ....................... 96

P. 

Pan tell arito....................... 96

Pearlite........................ 134,189

Peridotite ....................... 74, 79,

91,92,94,98,140,165, 205, 231 

Phlogopite........................ 115

Pliouolite ............... 77,114,161,162

Phtbanite...... .................. 286

Pbyllite .......................... 70,90

Piorite......................... 140,146

Pitcbstone...................... 79,168

PLigioclase-andesite.............. 163

Plagioclase-basalt.. ...\ .......... 163

Plagioclase-gueiss................ 215

Porpbyrite ............. 97,117,119,138,

142,143,173,175,178,180,

183, 187, 208,213,214,216

Porpbyrite-diorite................ 178

Porpbyry .... 68,69,95,102,107,119,122,

123,124.132,133,142,146,150,

161,155,156,172,173,176,181,

183, 191, 201, 206, 207,217,232

Pseudo-diabase................... 222

Pseudo-diorite.................... 222

Pseudoleucite-sodalite-tinguaite.. 157 

Pseudoleucite-syeuite ............ 154

Pumice..................... 141,198,229

Pyroxene... .................... 84,105,

116,137,158,171,182,185,230 

Pyroxene-andesite....... 120,134,135,195

Pyroxeue-iuica-diorite............ 117

Pyroxene-porphyrite ............. 117

Pyroxene-schist.................. 113

Pyroxenite.................. 83,140,224

Q. 

Quartz-alunite rock .............. 169

Quartz-aridesite.................. 207

Quartz-banakite.................. 128

Quartz-basalt.................. 198,199

Quartz-diaspore rock............. 169

Quartz-diorite............... 143,204,214

Quartz-diorite-gneiss. ............ 214

Bull. 148 20

Page. 

Quartz-diorite-porphyry........ 124,206

Quartz - hornblende - mica - porpbyrite ............................ 175

Quartzite .................. 108,109,110

Quartz-mica-diorite .... 118,124,206,220

Quartz-mica-diorite-porphyry .. 119,124 

Quartz-pantellarito............... 96

Quartz-porpbyrite.. .175,178, 208, 214,216 

Quartz-porpbyrite-scbist.......... 214

Quartz-porpbyry ................. 67,

81,102,146,150,201,232 

Quartz-pyroxene-diorite........... 218

Quartz-schist..................... 90

Quartz-syenite ................... 156

Quartz-syenite-porphyry ....... 148,156

Quartz-tourmaliue-porpbyry...... 150

R.

Rbyolite ........................ 81,130

131,132,134,150,151,167, 

168,170,174,177,179,184, 

188,192,202, 214, 228, 229

Rbyolite-pitcbstone .............. 150

S. 

Sandstone....................... 92,210

247,248,249, 250,251,252 

Saussurite-gabbro ................ 100

Saxonite ......................... 231

Schist........... 78,90, 98, 99,100,101,113

114,214,221, 222,224,228 

Sericite-schist.................... 90,99

Serpentine........................ 72,

73,203,205, 209,223,226,227 

Shale ........... 92,282,283,284,285,286

Shell rock.................. 259,260,276

Shonkinite...................... 149,157

Sboshonite..................... 126,129

Siderite .................... 266,267,268

Slate....... 109, 277, 278,279,280,281,283

Smaragdite....................... 83

Sodalite......................... 66,154

Sodalite-syenite.................. 154

Solvsbergite...................... 145

Spberulites....................... 170

Spilosite ......................... 97

Syenite....... .....:............ 68,143,

147,151,153,156,158,169,217 

Syenite-diorite-porphyry ......... 148

Syenite-porphyry......... 68,69,147, 217

T.

Tacbyly te........................ 79

Tallow clay................ 293,295,296

Theralite .................. ...... 145

Tihguaite.................. 145,157,182.
306 INDEX TO ROCKS.

Pagu

..... 74

114.

Trachyte . . 115, 132, 145, 152, 163) 165, 186

Troilite .....................

U.

V.

Voaresite ....................

... 131,132

..... 246

..... 209

..... 205

..... 179

..... 152

Volcanic ash .............

W.

' Y. 

Yocoite ...................

Page. 

........ 229

141

........ 141

84, 92, 224 

....... 77,140

........ 215

........ 115

......... 156