SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

GEOLOGY OF THE LATAH FORMATION IN RELATION TO THE LAVAS OF COLUMBIA 

PLATEAlJ NEAR SPOKANE, WASHINGTON 

By J. T. PARDEE and KIRK BRYAN 

SUMMARY 

The name Latah formation is proposed for a series of beds 

consisting mostly of clay and shale and of fresh-water origin 

that are found near Spokane, Wash., and thttt contain an 

abundant middle or lower Miocene flora. · The formation is 

found in Latah Creek valley for 10 miles south of Spokane, on 

tributaries of Little Spokane River for 20 miles north of the 

city, and in places in Spokane Valley for 8 miles northwest and 

5 miles east of the city. It occurs also in at least one place in 

the broad, open valleys of the mountains near Coeur d'Alene, 

Idaho. · These beds rest upon a rough surface of granitic and 

schistose rocks of unknown .age, attain a maximum thickness 

of 1,500 feet, and are overlain by "rim rock" basalt flows, 

probably Miocene; "valley" flows, probably later Tertiary; 

and gravel of Pleistocene age. Sills and dikes, which represent 

some of the conduits through which the "rim rock" basalt rose 

to the surface, cut and to a small extent deform the Latah 

beds, which otherwise retain their original horizontal attitude. 

During Latah time the lava_floods of the Columbia Plateau, 

advancing from the west, were held back from the Spokane 

area by a ridge, the highest parts of which now form the hills 

near Cheney, Marshall, and Medical Lake. The drainage outlet 

of this area was thus gradually obstructed by the lava, and the 

sediments here described were accumulated. Eventually the 

lava piled up until the "rim rock" flows were enabled to cross 

the protecting ridge and to overspread the area of Latah 

sediments. 

The "rim rock" flows consist of olivine basalt that shows 

very conspicuous columnar jointing. They are considered to 

be of Miocene age but are doubtless younger than the Yakima 

basalt. West of the submerged ridge they are apparently indistinguishable from the great series of flows that make up the 

Columbia Plateau. · 

Mter a time interval measured by the cutting of valleys 

through the "rim rock" basalt and to a known depth of 800 

feet into the Latah formation another series of basalt flows, 

referr~d to as "valley" flows, were extruded. These flows 

occupy parts of the erosional va~leys and rest unconformably 

upon the Latah, exhibiting at the contact "pillow structure" 

and other characteristic features. They are distinguished from 

the "rim rock" flows largely by their toppgraphic position, by 

a more varied jointing, and by the absence of olivine. 

INTRODUCTION 

The Latah formation, as a whole, has been studied 

only in the general vicinity of Spokane, Wash., 

although there is evidence, from collections of fossil 

leaves, that it extends eastward into the open valleys 

near Coeur d'Alene, Idaho. Much information concerning this formation has been gathered by local 

students, whose work in collecting fossil leaves is 

further noted below, The w<;>rk of the writer~ has .been 

incidental to or a part of other geologic work and 

consisted in a study of the Pleistocene features of 

Spokane Valley by Mr. Pardee at times during 1922 

and 1923 and a geologic examination of the general 

area by Mr. Bryan, in connection with his work on the 

Columbia Basin irrigation project, in 1923. The 

unexpected extent of the leaf-bearing beds and their 

interesting relations to the lava flows seem to justify 

as complete a description of the formation as is now 

possible and an account of its fossil localities. The 

large flora is described by F. H. Knowlton on pages 

17-50. As elsewhere noted, specimens of the basalts 

were studied under the microscope by F. C. Calkins, 

who also read the text and offered helpful criticisms. 

Edward Sampson studied under the microscope 

specimens from the Latah formation and from the 

fragmental rock inclosing the "pillows" of the" valley" flows. 

COLLECTION AND OCCURRENCE OF THE FOSSILS 

The fossil plant remains from the beds described 

were mostly collected and given to the United States 

Geological Survey and the United States National 

Museum by Mr. Henry Fair, Mr. C. 0. Fernquist, 

and Prof. T. A. ,Bonser, of Spokane, and by Mr. H. J. 

Rust, of Coeur d'Alene. A small but valuable part of 

the collection was contributed by Prof. Thomas 

Large, of Spokane, who shares the credit for collecting 

it with Miss Doris Burchett, a high-school student. 

Dr. R. W. Chaney, of the Carnegie Institution of 

Washington, added a valuable lot of these plant 

remains which he had collected several years before, 

and the whole was further enriched-by a large number 

of specimens obtained by Mr. Bryan in 1923~ To all 

the local collectors much credit is due for the discrimination and care with which they selected and marked 

the specimens. 

The fossils are unusually well preserved. As 

described by Mr. Knowlton, they represent an 

ancient and varied flora that was very different from 

the native vegetation growing about Spokane to-day. 

The collection is of particular value because it comes 

from a locality not before studied in detail and gives 

evidence bearing on the geologic age of the vast lava 

flows that form the Columbia Plateau of Oregon, 

Washington, and Idaho. 

1 
2 SHORTER CONT'RIBUTIONS TO GENERAL GEOLOGY, 1925 

Fossil plant remains have been known in the 

neighborhood of Spokane for a considerable time and 

were mentioned by Russell 1 as long ago as 1897, but 

so far as the writers are aware no description of the 

fossils or their · occurrence has been published heretofore. From time to time the excavation of street and 

railroad cuts has exposed fossil-bearing beds, and a 

few years ago local interest in fossils was somewhat 

stimulated by the finding in the Division Street cut of 

a charred tree trunk inclosed between two ancient 

lava flows. ·Recently Professor Bonser, aided by his 

pupils, has collected ·a large number of the fossil leaves 

, and other remains, which he has placed on exhibition 

in the Spokane Public Museum. The field work of 

the other collectors was done at odd times from 1920 

to 1923. 

Prairie. Fossil plant remains have also been found on 

the south side of Indian . Canyon just above the falls, 

in Biglow Gulch about 2 miles northeast of Hillyard, 

in road cuts in sec. 31, T. 52 N., R. 44 E., and sec. 29, 

T. 51 N., R. 44 E., and in· Spokane between Cannon 

Hill and Union Park ~nd at the intersection of Thirteenth Avenue and Perry Street. 

Most of the fossil-bearing localities mentioned are 

within a radius of 10 miles from Spokane, and all may 

be included in an area 10 or 20 miles wide that extends 

from Coeur d'Alene, Idaho, westward 35 to 40 miles 

along Spokane River. All the localities are shown on 

the index ·map (fig. 1). This area of fossiliferous beds 

lies about 150 miles east of Ellensburg, Wash., the 

nearest place at which plant-bearing beds associated. 

with similar lavas have been found. 2 Other ~ore 

FIGURE I.-Index map showing position of fossil localities near Spokane, Wash.; ·and location of area covered 

by Plate I · · 

The larger part of the collection was obtained at 

the following places: Deep Creek half a mile above 

its mouth; in the cuts of the Spokane, Portland & 

Seattle Railway and the Chicago, Milwaukee & St. 

Paul Railway in Spokane west of Latah Creek; at 

Thor Street and Twelfth A venue, Spokane; and at 

the Edwards ranch, Stanley Hill, near Coeur d'Alene, 

Idaho. The remainder came from a clay pit at the 

edge of the Spokane Valley, 2 miles south of Vera; 

from a well a quarter of a mile west of Mica; and from 

outcrops at the Schuele ranch and in a ravine, on the 

slopes south and southeast respectively of Fivemile 

t Russell, I. C., A reconnaissance in southeastern Washington: U.S. Geol. Survey 

Water-Supply Paper 4, p. 53, 1897. 

distant areas in the ge~eral region that contain floras 

of somewhat similar occurrence are mentioned in the 

paper by Mr. Knowlton. 

SURFACE FEATURES OF THE REGION. 

The area considered herein li~s along the border 

between the Great Plains of the Columbia, or the 

Columbia Plateau, and the mountains of northern 

Idaho and northeastern Washington. It includes 

parts of the valleys of Spokane and Little Spokane 

rivers, together with adjoining parts of the mountains 

2 Smith, G. 0., U.S. Geol. Survey GeoL Atlas, Ellensburg folio (No. 86), p. 3, 1902, 

Russell, I. C., A geological reconnaissance in central Washington: U. S. Geol. 

Survey Bull. 108, p. 103, 1893. 
U . S . OEOI.O(;)(' .\L :-'I' H\'F Y I'ROFES[,;JO:-.;AL 1'.\ I'EH 110 1'1.:\TE I 

RECONNAISSANCE GEOLOUTC MAP OF AHEA NEAH SPOKANE, WASI-l. 

A- A', B- B', liues of sec tiou~ iu Figure>~ 2 uud 3 

EXPLANATION 

~ 

~ 

Alluvium 

>- a:: 

<t 

z 

(l: 

(Mostly sand and grar-el vJ ola..--ial out. UJ 

u~h plai1't.' frnt including Pll'"ist.ocen'- ~ lake tH>ds a11d Recent strt-am depMits. :J 

Map{>t'd <mlytchere so thick as to ron. 0 CI!(J/ the older rV('/.;~) 

(Flows, mostlll in t'<llleya) ) 
GEOLOGY OF THE LATAH FORMATION 3 

and the plateau. The general setting of the area is 

shown in Figure 1, and the area immediately adjacent 

to Spokane is shown on the geologic map (Pl. I). 

Spokane lies at the northef}.st corner of the Columbia 

Plateau. From the hills east of the city this feature 

appears as a plain stretching away to the horizon on 

the south and west. It owes its general character to 

the fact that it is built up of vast lava flows that 

remain nearly as level as when they cooled. Because 

the liquid masses advanced upon a mountainous 

region the edge of the plateau is sinuous and irregular. 

South of Spokane it projects into the mountain valleys 

and retires around the intervening spurs like the 

coast line of a sea, and this fancied resemblance is 

increased by the fact that here and there isolated 

hills rise a hove the plain like off -shore islands. Westward from Spokane the present northern boundary 

of the plateau is the valley of Spokane River, a feature 

of more recent origin. North and east of the river 

isolated mesas or plateaus capped by basalt show 

that before the valley of Spokane River and its 

tributaries were cut that part of the plateau margin, 

like the stretch sout.h of Spokane, was exceedingly 

sinuous. 

In the neighborhood of Spokane the general altitude 

of the plateau is about 2,400 feet above the sea; its 

surface appears to be level or to slope gently northward, and it drains toward Spokane River. At a 

distance of 10 or 12 miles west of Spokane is an 

inconspicuous divide, beyond which the plateau descends gradually to the southwest for more than 100 

Iniles. . Considered in detail the plateau surface near 

Spokane is considerably roughened. The streams 

tributary to Spokane River have cut valleys into it 

several hundred feet deep, which exhibit crags, cliffs, 

and terraces at different levels. 

The area immediately east and north of the Columbia Plateau is characterized by Wide valleys, smoothly 

contoured slopes, and mountains of moderate height. 

Between Spokane and Coeur d'Alene the local relief 

ranges from 100 to as much as 3,000 feet. Farther 

east it is greater. The change from plateau to hills 

or mountains is generally a·brupt, definite, and without 

gradations, but commonly a small depression is found 

between the edge of the basalt and the foot of the 

mountain slope. 

From Spokane a wide depression extends eastnortheastward into the mountainous area as far as 

the head of Pend Oreille Lake. It contains a level 

floor that in the vicinity of Spokane is about 2,000 

feet above the sea', or 400 feet below the Columbia 

Plateau. Eastward the floor rises gradually, its 

general altitude in the neighborhood of Coeur d'Alene, 

about 30 miles from Spokane, being 2,300 feet. Along 

the sides of this depression in tributary valleys are 

several beautiful lakes, including Coeur d'Alene Lake, 

that are well known as summer resorts. So far as 

.the writers are aware there is no name in use fo~ tlfis 

depression as a whole. For a distance of 15 or 26 

miles east of Spokane it is known as Spokane .V al~ey. 

Beyond this a part lying between Coeur d'Alene and 

Rathdrum, Idaho, is called Rathdrum Prairie, and 

the remainder is known by different names. 

Spokane River, the outlet of Coeur d'Alene Lake, 

flows through Spokane Valley in a shallow trench to 

the falls at Spokane. Below this point it occupie~ a 

deep gorgelike valley, bordered by prominent cliffs 

and terraces, that extends northwest along the edge 

of the Columbia Plateau. This valley, . :which by 

reason of its generally rugged character contrasts . 

strongly with the valley above the falls, or Spokane 

Valley proper, is commonly known as the gorge or 

"lower valley" of Spokane River. 

On the north side of Spokane Valley opposite 

Spokane is a small " table-land or plateau known as 

Fivemile Prairie (Pl. 1). Its flat summit is nearly 

2,400 feet in altitude, and its upper part is composed 

of two or more horizontal sheets of lava:. Evidently 

it once formed a part of the Columbia Plateau, from 

which it has been cut off by Spokane River~ Pleasant, 

Green Bluff, Orchard Bluff, and Scabland prairies 

are similar outliers of the plateau that extend north 

from Spokane on the east side of the valley of Little 

Spokane River. The general appearance of these 

table-lands or mesas may be judged from Plate II, 

A, a view of the northwest slope of Pleasant Prairie. 

Here and there east of Spokane . on both sides of the 

valley are shelves at or near the 2,400-:foot contour 

formed by patches of lava clinging to the sides of 

the valley. The most extensive one observed is at 

the north of Hayden Lake. Others appear on the 

shores of Coeur d'Alene Lake and along the lower 

courses of Coeur d'Alene and St. Joe rivers. All 

are interpreted as remnants of the highest and last 

of the lava flows that built the Columbia Plateau and 

once overspread Spokane Valley and its tributaries. 

Patches of lava that form small masses and benches 

from 1,800 to 2,100 feet in altitude occur along Spokane 

River at Spokane, near Milan, near Chattaroy, on 

HaJf Moon Prairie, and near Deer Park. These 

isolated outcrops are interpreted as remnants of ·the 

plain. formed by the most recent flow of the region 

as described on page 13. 

Latah Creek and Deep Creek, which join the river 

below Spokane and drain adjoining parts of the 

Columbia Plateau, have excavated deep valleys 

similar in character to the valley of Spokane River 

below Spokane Falls. Viewed from Manito Prairie, 

the plateau remnant south of Spokane, across the 

deep valley of Latah Creek, the Columbia Plateau, 

bounded by its black cliffs, stretches out to the 

horizon, as shown in Plate II, B. 
4 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

Out on the plateau 8 or 10 :miles from Spokane are 

several hills that stand out faintly on the sky line. 

These "islands" or "step toes" are knobs and ridges 

of granite and similar rocks that project through the 

lava. Together they form a broken chain of hills 

extending from Silver Hill west· and northwest to 

Browns Butte, Marshall, Cheney, and Medical Lake. 

Probably to be included with them are two small 

knobs farther northwest, beyond Deep Creek. (See 

Pl. I.) These hills, as explained on page 10, lnark 

the position of a buried ridge that for a time held 

back the advancing lava flows and permitted the 

leaf-bearing sediments to accumulate undisturbed in 

the neighborhood of Spokane. Finally, however, the 

lava overflowed and submerged the ridge until only 

its highest summits stood above the igneous flood. 

ROCKS 

GRANITE-SCHIST GROUP 

The mountainous· part of the area cons1uered is 

composed chiefly of crystalline and · metamorphic 

rocks, such as granite, gneiss, and schist, with small 

masses of quartzite. In addition rocks of this group 

form the encircling chain of hills that rise above the 

plateau from Silver Hill to Medical Lake. On the · 

north side of Fiyemile Prairie, in numerous places in 

the other '' prairies'' east and north of Spokane, and 

down the gorge on Spokane River, granite and granite 

gneiss crop out beneath the lava and the fossil-bearing 

shale, as shown on the geologic map (Pl. I). It is 

evident, therefore, that in addition to composing the 

hilly areas these rocks extend beneath the plateau as 

a basement or floor upon which the sediments and 

lavas rest. To judge by the degree of crumpling and 

metamorphism it exhibits, the schist is very ancient. 

. The granitic rocks that intrude it are younger, but all 

members .of this group are much older than the lava, 

the fossil-bearing shale, and the gravel that lie unconformably upon them. A detailed description of the 

granite-schist group as it occurs at Silver Hill, southeast of Spokane, is given by Collier,3 and for Stevens 

County by Weaver.4 

LATAH FORMATION 

GENERAL. FEATURES 

The fossil-bearing beds that overlie the graniteschist group are distributed through an area extending 

from the mouth of Deep Creek east-southeastward to 

Coeur d'Alene, Idaho, and 20 miles north of Spokane 

to Dry Creek, near the town of Elk. Owing to the 

fact, however, that they are composed of soft and 

easily erodible materials, · they have been largely 

a Collier, A. J., Tin ore at Spokane, Wash.: U. S. Geol. Survey Bull. 340,pp. 

29&-305, 1908. 

• Weaver, C. E., The mineral resources of Stevens County, Wash.: Washington 

Ueol. Survey Bull. 20, 1920. 

·washed away wherever they were not protected by a 

covering of basalt, and their areal exten:t therefore is 

small. (See Pl. I.) The vertical range of their exposures 

amounts to as much as 800 feet, the lowest, which is 

near the mouth of DeeP, Creek, being at an altitude 

of about 1,650 feet, and the highest, near Mica, at 

about 2,450 feet. 

The fossil-bearing beds consist mostly of shale or 

clay, with a few layers of sand and gravel. The colors 

range from pale yellowish gray to lead-gray or bluish 

gray, the prevailing shades being rather dull. Locally 

the beds show pale tints of brown and streaks of rusty 

red. Glistelling specks of white mica occur abundantly 

in most of the beds. The coarser layers are composed 

chiefly of quartz and fel4spar grains derived by 

erosion from the rocks of the granit,e-schist group. 

No beds were observed to contain pebbles or grains 

of basalt. Approximate analyses made in the laboratory of the Geological Survey show the clays to contain 

from 45 to 70 per cent of silica and from 15 to· 30 per 

cent of alumina. 

A microscopic examination by Edward Sampson of 

specimens of the shale from . the neighborhood of 

Latah Creek indicates that much of the finer-grained 

material composing the shales is of volcanic origin. 

These specimens contained sharp-edged grains of 

quartz and fresh grains" of plagioclase feldspar and 

biotite mica that can hardly have been derived from 

the rocks of the granite-schist group and seem more 

likely to have been derived from showers of volcanic 

ashes of an andesitic type that fell in the region 

during the period of sedimentation. The lack of 

volcanic glass, so far unidentified in the specimens, is 

difficult to explain. The lamination of the beds 

indicates that the material of the ash showers was 

thoroughly reworked by streams an4 probably more 

or less mixed with the products of the erosion of the 

granite-schist highlands to the east. 

In weathering the shale usually becomes brownish 

yellow and loses its lamination and jointing. Stains, 

spots, and seams of limonite are formed. Usually 

also there is a surface crust from a quarter of an inch 

to 2 inches thick composed of sand and limonite so 

. hard that pieces ring under the hammer. The crust 

is frequently broken in plowing, and the flakes are 

picked up and piled in heaps at the edges of the fields. 

The clayey character of the weathered shale makes it 

a notable soil in a region where most of the soils are 

sandy. ~n some places the weathered surfa~e of the 

shale is leached to a whj.te impure kaolin, which 

retains, however, flakes of mica and leaf impressions. 

This white phase of the weathered surface and also 

the ordinary type are used near Spokane and at Vera 

for making common brick and tile. 

Where the .beds rest on the · underlying granite 

gneiss they usually consist of arkosic gravel that 

gra<;les by interbedding into the characteristic clay 
GEOLOGY OF THE LATAH FORMATION 5 

shale. Clay with scattered small pebbles and clayey 

gravel were found interbedded with the typical . clay 

shale in the test holes drilled in 1923 at the Latah 

Creek dam site of: the Colun;tbia Basin project. 

WCAL DETAILS 

SECTION AT DEEP CREEK 

On the west bank of Deep Creek about half a mile 

above its mouth, at a locality that is shown in Plate 

III, A, and that has yielded a large part of the collection of fossil leaves described by Mr. Knowlton, 

the shale is exposed as follows: 

Section on Deep Creek half a mile above its mouth 

Feet 

Sand, rusty red; contains quartz pebbles and flakes of · white mica _____________________________ --_________ 15 

Shale or clay, thin bedded, lead-gray, with a few rusty-red 

layers. Contains abundant fossil leaves. At bottom 

a thin layer with fragments of wood partly changed 

tolighite--------------------------~-------------- 15 

Shale, massive, bluish gray____________________________ 20 

Clay, containing fragments of tree stumps and stems that 

are partly altered to lignite__________________________ 2 

Bottom not exposed. 

As determined by aneroid the altitude at the base · 

of this exposure is 1,650 feet. Above the rusty red 

sand at the top are basalt cliffs and talus-covered 

slopes rising 600 feet or more to the summit of the 

p]ateau. The beds appear to be horizontal. 

SECTIONS WEST OF LATAH CREEK Il'l SPOKANE 

Several cuts along the Spokane, Portland & Seattle 

'and Chicago, Milwaukee & St. Paul railways in the 

city of Spokane west of Latah Creek expose the fossilbearing shale. About three-quarters of a mile south 

of the Sunset Highway bridge over Latah Creek are 

cuts near each other on these two railways, which for 

convenience will be referred to asS., P. & S. cut No.1 

and Milwaukee cut No. 1. The following section wa:s 

measured inS., P. & S. cut No. 1 at an altitude of 

about 1,950 feet above the sea: 

Section in cut of Spokane, Portland & Seattle Railway in Spokane 

Feet 

Surface mantle containing large masses of basalt______ 6 

1. Sand, white to red, moderately fine, composed of rather 

sharp grains of quartz, feldspar, and other minerals__ 5 

2. Shale; rusty yellow, yields fossil leaves_______________ 10 

3. Hardened clay; massive, light gray__________________ 12 

Bottom not exposed. 

Bed 1 is cleanly washed stream sand that fills a 

channel eroded in the other layers. Many of the 

plant remains described by Mr. Knowlton were 

obtained from bed 2. There is no break between 

beds 2 and 3, and despite the erosional unconformity 

beneath bed 1 all are considered as belonging to the 

same series. Apparently the two lower beds were 

deposited in a pond or other low place so as to form 

a mud flat .across which a gently flowing stream later 

spread the sand of bed 1. In places in this and some 

of the other cuts, as mentioned farther on, dikes and 

sills have intruded the beds, causing them to dip at 

moderate angles. Away from these disturbing features the beds appear to be horizontal and uncleformed. 

On the slope directly above this cut, along a road 

that passes through a subway on the abandoned 

electric-railroad grade, yellowish-gray clay and layers 

of cross-bedded sand are exposed. These beds are 

similar in composition and appearance to those in the 

railway cut and are regarded as belonging to the 

same series. They are overlain by the lowermost of 

the basalt flows known as the ''rim rock,'' described 

on page 11, the base of which is at an altitude of 

about 2,250 feet. 

Between the two exposures the slope is covered and 

the underlying formations are concealed by a rather 

thick mantle containing fragments and scattered large 

masses of basalt that apparently are the weathered 

remnants of later flows. Presumably the shale formation is continuous beneath this mantle; if so, its 

total thickness from the floor of the railway cut to the 

base of the "rim rock," exclusive of a 50-foot sill, is 

about 250 feet. 

South of S., P. & S. cut No. 1 other cuts on both 

this railway and the Chicago, Milwaukee & St; Paul 

Railway expose the shale at successively higher altitudes up to about 2,050 feet, the highest being at a 

distance of 2 miles in the third cut to the south on 

.the Spokane, Portland & Seattle Railway. Here 20 

feet or more of light-gray shale that yields abundant 

plant remains is exposed. 

At the contact With the intrusive dikes and sills the 

shale commonly appears darkened, but in places it is 

nearly white and baked almost to the consistency of 

porcelain. In Milwaukee cut No. 1 a mass of shale 

nearly surrounded by the intrusive rock (Pl. IV, B) 

shows a peculiar jointing th,at causes it to separate ip.to 

slender curved columns, the size of a pencil or smaller, 

radially arranged about the centers of ordinary joint 

blocks a foot or less in size. · 

On the front of the spur between Latah and Lake 

creeks half a mile east of a cut on the Spokane, Portland & Seattle Railway a sand pit shows the following: 

Section in sand pit of H. Feise, south of Spokane 

Talus composed chiefly of basalt fragments __________ _ 

Clay, massive, yellowish gray ______________________ _ 

Clay, sandy, micaceous, dull gray, indistinctly bedded; 

fragmentary plant remains near top_ ... _____________ _ 

Sand, cross-bedded', medium-sized grains, cleanly washed, 

composed chiefly of quartz and feldspar grains· and 

flakes of mica __________________________________ _ 

Feet · 

10 

' 5 

10 

20 

The cross-bedding in the 20-foot layer inclines 

northwestward, as if the sand had been deposited by a 

stream flowing in that direction. The altitude at the .. 
6 SHORTER CONTRIBUTIONS TO< GENERAL GEOLOGY, 1925 

base of the exposure 1s about 2,100 feet. A second 

sand about 20 feet lower has been uncovered in a small 

pit below which is a spring that is obviously fed by 

water stored in the two sand beds. The slope below 

is covered by soil and terrace gravel to an altitude of 

about 1,980 feet, and at that level a sill crops out that 

at the Latah Creek dam site, about a quarter of a 

mile away, has a thickness of more than 250 feet. 

OTHER EXPOSURES 

A particularly valU:able part of the fossil collection 

came from a well on the Edwards ranch, about 2 miles 

northeast of Coeur d'Alene, Idaho. When this place 

was visited by Mr. Pardee early in July, 1923, .no 

exposures of the fossiliferous beds were to be seen. 

The well is on a bench on the south slope of Stanley 

Hill, at an altitude of 2,4;00 feet. It is said to be 43 feet 

deep, and the plant remains were found near the bottom. Remnants of basalt flows that appear to overlie the shale crop out near by, and granite and schist that 

form the bedrock are exposed a little farther away. 

The matrix of the specimens. from this well is of a 

dull-gray color; resembling that from most of the 

other fossil localities, but an approximate analysis 

shows it to contain less silica and more iron and 

alumina than the average. 

At Thirteenth Avenue and Perry Street, in the southeastern part of Spokane, thin-bedded soft sediments 

that range from clay to fine sandstone are exposed to a 

thickness of 8feet. The beds are gray, dip about 4° N., 

contain grains of quartz and flakes of white 1nica, and 

are stained rusty red on bedding planes and joints ~ 

Fossil leaves are present but not abundant or well 

preserved. The altitude is about 2,050 feet. 

Very light-colored beds that contain abundant 

fossil leaves and are composed of clay, fine quartz sand, 

and white mica crop out at an altitude of about 2,100 

feet in a ravine at the Schuele ranch, on the slope south 

of Fivemile Prairie, and in the cuts of the new county 

road on the north slope_ of the same "prairie," where 

fragmentary plant remains were found. The beds are 

about horizontal and are overlain by basalt, but their 

base is not exposed. A deposit of similar clay described by Shedd 5 occurs on the farm of W. G. Lake, 

6 miles north of Spokane. 

In a gulch on the slope southeast ~f Fivemile 

Prairie, ~bout 1 ~ miles east of the Schuele ranch 

. locality, 40 feet of shale that contains leaf-bearing 

layers is exposed. It shows the dull-gray shades and 

other features common to the shale elsewhere. The 

altitude at the base of the exposure is 2,120 feet. 

Slopes above and below are covered with loose fragments of basalt and soil. A flow in place corresponding 

to the "rim rock" crops out at 2,240 feet. 

Somer's clay pits, about 2 miles south of Vera, expose 

20 or 30 feet of compact micaceous white, yellow, and 

5 Shedd, Solon, The clays of the State of Washington, their geology, mineralogy, 

and technology, pp. 172-174, Washington State College, 1910. 

red clay in nearly horizontal beds that contain fossil 

plant remains. · The clay lies upon rocks of the granite- _ 

schist group and occurs at an altitude of about 2,100 

feet. The basalt cover has been _stripped away by 

erosion, and the beds are. now overlain by a thin cover 

of valley gravel. 

Specimens obtained at Mica, Wash., are said to 

have come from a well at an altitude of ,2,450 feet. 

They. consist ,of brownish-gray clay ?r shale that is 

noticeably light in weight. The microscope shows it 

to be composed largely of very ·small cylinders and 

other hollow forms that are the siliceous skeletons of 

the minute water plants known as diatoms, described 

by Mr. Mann on pages 51-55. In addition the shale 

contains fine grains of quartz, mica, and other minerals 

derived from the granite and schist of the adjoining 

hills. Evidently the deposit was formed in a pond 

or marsh. It may be classified as impure diatomaceous earth and also as brick clay, but it is of 

different origin from the residual clays at Mica and 

Freeman, near by, which have been described by 

Shedd. 6 Evidently this deposit rests upon rocks of 

the granite-schist group. . 

Along the · road up Biglow Gulch about 2 miles 

northeast of Hillyard the shale is exposed at an 

altitude of 2,200 feet. It lies upon granite and 

beneath a basalt fl~w at 2,300 feet corr:esponding to 

the ''rim rock.'' 

In Indian Canyon, above the falls, is a small exposure of fossiliferous shale at an altitude of 2,200 

feet, just above the outcrop of a basalt flow. The 

field relations suggest that the shale lies upon the 

flow which if this is true, should be correlated with 

the 'upper ~ne of the two flows encountered in the 

Hazelwood well (p. 10). However, the evidence is 

not decisive, and the basalt may belong to the "'valley" 

flows and rest unconformably on the shale. .· 

Sediments that doubtless are equivalent to the 

fossil-bearing beds described above are penetr~ted by 

several drilled wells-the Hazelwood well, 7 miles 

west of Spokane; the Hinch well, 18 miles southeast 

of Spokane; and the Davenpor~ Hotel ~nd La~ahTexas wells, in the city. The InformatiOn denved 

from these wells is given on pages 8-9. 

Above Medimont in the valley of Coeur d'Alene 

River,. about 35 miles east-southeast of Spokane, are 

fine white and variegated sediments ·described by 

Hershey 7 as having accumulated in a lake caused 

by a dam formed of basalt. Appa:::-ently the basalt 

referred to is a remnant of the last or highest flow of 

Columbia Plateau. No fossils are reported from these 

beds. ~ 

DEFINITION 

From the foregoing descriptions It appears certain 

that, except for some later intrusiv:e rocks, the slope 

west of Latah Creek from the railway_ cuts to the 

6 Shedd, Solon, op. cit., pp. 181-194. 

1 Hershey, 0. H., Geol. Soc. America Bull., vol. 23, p. 529, 1912. . . 
GEOLOGY Oil' THE LATAH FORMATION! 7 

"riln rock" is underlain by the fossil-bearing shale 

and associated beds, which aggregat~ at least 250 

feet in thickness. Although there is no continuous 

exposure of such a thickness, the different places at 

which horizontal beds are shown at successively 

higher levels are comprised within so small an area 

that there is little room for doubt that all the exposures are parts of a continuous formation. 

Inspection of the several "prairies" north and south 

of Spokane reveals similar relations. Each of these 

pleateau remnants has a cap or "rim rock" at an 

altitude of about 2,400 feet. Below the "rim rock" 

there are smooth soil-covered slopes, mostly in cultivation, as illustrated in Plate II, A and B. These 

smooth slopes are underlain by the clay beds, as 

shown by the clayey texture . of the soil, by the 

presence of flakes of limonite characteristic of the 

weathered surface of the beds, and by scattered 

exposures in wells and road cuts. 

In these localities the beds lie unconformably upon 

the rocks of the granite-schist group. They consist 

chiefly of fine sediments. Their fossils, as described 

farther on, indicate that they are all of the same age; 

and therefore all are regarded as parts of the same 

formation, . for which the name Latah is proposed. 

The Latah formation, consequently, ' may be defined 

as consisting chiefly of clay and shale with some beds . 

of sand and gravel and one or more beds that contain 

sufficient quantities of diatom skeletons to be classed 

as an impure diatomaceous earth. Many of the shale. 

beds appear to be composed largely of very fine 

volcanic ash. The shale generally contains plant · 

remains, which, as described by Mr. Knowlton in the 

following paper, are of middle or lower Miocene age. 

The formation is at least 250 feet thick in the area of -

typical exposure oil the slope west of Latah Creek, 

and its range in thickness in the Spokane-Coeur 

d'Alene area ~s from 1,500 feet to the vanishing point. 

In the Spokane area, so far as known, it rests everywhere upon the granite-schist group, and apparently 

it is or was at one time covered everywhere by the 

lava flows composing the "~im rock." Formerly it 

extended continuously over the area from the Silver 

Hill-Cheney ridge north and east to the mountains, 

except for the "islands" or "step toes" of crystalline 

rock, many of which were not covered even by the 

highest lava flow. South and west of the ridge yhe 

extent of the formation is not definitely known T d 

the upper beds are surely absent. (See p. 10.) 

STRUCTURE 

Where exposed by the railway cuts west of La ah 

Creek the shale of the Latah formation has been f.eformed by intrusive bodies of igneous rock. A sill 50 

feet or more thick, particularly well shown in S., £ & 

S. cut No. 1 and Milwaukee cut No. 1 has forced ts 

way along a bedding plane, lifting and tilting he 

overlying shale. In places the intrusive rock takes 

the form of dikes that break across the beds and 

displace them slightly. This deformation, however, 

is con:fin:ed to the vicinity of the intrusive bodies. In 

Biglow Gulch northeast of Hillyard and at Thirteenth 

A venue and Perry Street and on Thor Street in Spokane 

the shale dips 4°-10° N. Whether this attitu<;le is the 

result of an intrusive igneous body is not shown, but 

there is no reason to thi!lk it may be due to any other 

cause. · Elsewhere from Deep Creek to Coeur d'Alene 

and from Duncan to Milan the beds of shale, wherever 

they can be seen, are horizontal. 

ORIGIN 

Before the Latah formation was deposited and the 

lava of the Columbia Plateau was extruded the rocks 

of the granite-schist group formed the surface in this 

area, the topography of which was apparently even 

more rough than the mountainous lands north and 

east of the plateau are at present. The sectio~ along 

the northern border of the plateau made by Spokane 

and Columbia rivers shows the relief of the old surface 

to be as much as 1,600 feet. At Spokane, as indicated 

by the Latah-Texas well (p. 8), there is a submerged valley at least 1,000 feet deeper than the 

present one. The 1,100, feet of lava and sediments 

penetrated by the Hazelwood well (p. 10) probably 

fill the ancient prolongation of this old valley. At 

the south of this buried valley is a ridge whose summits project through the lava to. form the chain of 

hills that extends from Silver Hill by way of Marshall 

and Cheney to Medical Lake and, as suggested by 

the smaller but otherwise similar hills of granite 

northwest of Deep Creek, probably continues 20 or 

30 miles farther northwest. (See Pl. I.) At Duncan 

the present valley of Latah Creek cro~ses this ridge, 

cutting deeply into the granite and schist. 

Most persons familiar with the Spokane area have 

been of the opinion that the fossil-bearing sediments 

described herein accumulated because the drainage 

was obstructed by lava flows advancing upon a 

mountainous region. Under this con~ition sediments brought down from the lands to the north and 

east would be deposited at the borders of the flows. 

Successive flows would result in a succession of sedimentary deposits, each one farther east or north and 

at a higher level than its predecessors. Thus it 

would be supposed, for example, that after the beds 

at Deep Creek were laid ·down a lava :flow extended 

eastward beyond that point, causing a new pond in 

which the beds at S., P. & S. cut No. 1 accumulated. 

Mter this process was repeated there would be a 

succession of lava flows alternating with layers of 

sediment partly extending ill front of them and partly 

interbedded with them. The information recently 

obtained in this area by the writers, however, makes 

necessary ·a modification of that idea so far as details 

• 
8 SHORTER CONTRIBUTIONS TO! GENERAL GEOLOGY, 1925 

are concerned. North of the buried ridge represented by the Cheney Hills no interbedded lava 

flows were found, except possibly at Indian Canyon 

(p. 6), and such ·flows are known only in the Hazelwood well, mentioned on page 10. The sediments 

appear to belong to a single formation that was completely deposited before any of the flows near Spokane 

and their related sills and dikes came to place. They 

accumulated in a basin that extended from the buried 

ridge north and northeast tb the limits of 'the area 

surveyed. As shown by the character of the sediments, this basin was at times occupied by ponds and 

at times became drained so that streams flowed across 

its floor. Leaves and wood of the forests growing on 

the neighboring lands and on the alluvial plains of 

the basin fell into the streams and, on being buried in 

the mud and sand, were preserved. 

The _ materials that form the leaf-bearing Latah 

formation were derived from explosive volcanoes 

and from the erosion of the granite gneiss of the 

mountains adjacent on the east. The finer beds are 

composed largely of volcanic ash of an andesitic type. 

The coarser beds are generally composed of grains of 

quartz and feldspar, but in some localities black and 

gray quartzite makes up about half of the grains, as 

shown by a study of samples from t:p_e drill holes at 

the Latah Creek dam site. At the Dry Creek dam 

site, near Milan, however, no quartzite was fouud, 

and this fact was used to distinguish the Latah gravel 

from the overlying flood-plain deposits. No basalt 

pebbles were found in any material from the Latah 

formation. _ . 

The character of the material and the type of rock 

composing the larger grains indicate that the formation as a whole was derived from the erosion of the 

region to the east but that local streams draining areas 

with slightly different bedrock carried on the work of 

deposition in ~ifferent places. It appears also that 

the formation was deposited in a basin at the foot 

of the mountains and in a period preceding that of any 

of the basalt flows now exposed on the surface in the 

Spokane region. Some beds were doubtless deposited 

in still water, as shown by their fine grain and delicate 

lamination. The leaves that are so beautifully preserved in m~ny beds are generally quite perfect and 

·lie parallel to the lamination of the shale. They were 

evidently floated into place rapidly but gently. Such 

beds must have been deposited in quiet ponded water 

and seem to indicate the presence of lakes. Other beds, 

however, contain the macerated remains of vegetation 

such as now accumulates in the bottoms of swamps. 

. The sand and fine gravel were deposited by currents, 

as shown by their cross-bedding, and doubtless represent the channels of streams. The Latah formation 

seems therefore to have been deposited in a broad plain 

of alluviation containing lakes and swamps, over which 

the streams from the mountains on the east found 

their way through sluggish channels toward the west. 

The cause of this ponding of the streams might, so 

far as evidence .from the fossil-bearing beds is concerned, 

be attributed either to local subsidence or to the building 

of a dam across the lower courses of the streams by 

the earlier and lower members of the basalt series 

that occupies the basin to the west. The idea of 

subsidence during deposition is unsuppprted by any 

evidence, but ponding of the drainage by lava flows 

is a hypothesis based on a number of ascerta-ined 

facts and logical inferences. The sediments of the 

Latah formation ·are earlier than any of the basalt 

flows that crop out in the immediate neighborhood 

of Spokane, except possibly the flow at Indian Canyon. 

(See p. 6.) On the other hand, the data derived from 

wells presented on page .10 indicate interbedding of 

th~ clay shale with flows west of Spokane. This 

seeming discrepancy has already been explained as 

due to the presence of the submerged ridge now . 

represented by the Cheney Hills and similar knobs, 

which acted as a barrier during .the time of extrusion 

of the basalts of the plateau to the west and held 

back the advancing lava. Thus while flow after flow 

desolated the general region of the Columbia Plateau, 

the Spokane area, owing to the protection afforded 

by the Silv~r Hill-Cheney ridge, was the scene of 

uninterrupted and quiet sedimentation until it too 

was finally overwhelmed by the flows of the "rim 

rock.'' 

Though the Spokane area was free of lava flows, 

showers of volcanic dust were sufficiently frequent to 

supply much of the material composing the shale. 

Mr. Knowlton, as set forth in the succeeding paper, 

believes that the· Latah formation is of middle or lower 

Miocene age and that it is to be correlated with the 

Ellensburg and Mascall formations. These formations 

consist in part of tuff beds. Volcanic debris in the 

Latah formation is to be expected, but the Spokane 

area doubtless lies at a great distance from the centers of eruption, for all the material attributable to 

volcanic· ·explosions so far found is of microscopic 

size. 

THJCKNESS 

As shown in the geologic eros~ section of Figure 2, 

the top of the Latah formation in the Latah Creek 

valley is at an altitude of 2,250 feet, and the floor of 

the valley is at 1, 7 50 feet. These figures indicate a 

thickness, including the intruded sills, of 500 feet. 

The :Yatah-Texas well, however, according to the drill 

samples shown to Mr. Bryan, after passing through 

the gravel of the flood plain and a thin layer of basalt, 

penetrated gray shale, dirty gravel, sand, and gravel, 

similar to material found elsewhere in the Latah formation, for 1,089 feet before entering the underlying 

granite gneiss. The total thickness of the Latah in 

this locality must therefore be from 1,400 to 1,500 feet. 
GEOLOGY OF THE LATAH FORMATION 

I 

9 

In the city of Spokane the well in the Davenport 

Hotel, after passing thr<?ugh 430 feet of gravel and 

basalt, entered shale and sand and ended. in gravel at a 

depth of 668 feet. (See fig. 3.) The sediments 

found in this well below the basalt are correlated with 

the shale that has been exposed in excavation at several 

localities in the · north slope of Manito Prairie up to 

the base of the overlying lava, at an altitude of 2,150 

feet, or about 250 feet above the Davenport Hotel. 

A minimum thickness of 918 feet is thus indicated 

beneath the central part of the city of Spokane~ 

~ 

§~ · SUNSET PRAIRIE 

~~ 

~ "Rim roc~' basalt flows 

EXTENT 

The distribution of the Latah formation is shown 

on the accompanying map (Pl. I). In many places on 

the slopes of the "prairies" it is concealed by talus, 

glacial till, and terrace gravel. In the Latah Creek 

valley the only good exposures are in the railway cuts 

previously described. In general a deep mantle of 

glacial gravel conceals the slopes, but an unusually 

detailed search for outcrops of the shale . and the 

intruded sills, together 1 with the results of drilling at 

.SE. 

MANITO PRAIRIE 

4 MILLS 

~~~----~----~--~----~ 

FIGURE 2.-Geologic cross section froUl Sunset Prairie to ridge 'east of Manito Prairie, Wash., along line A-A', Plate I 

Between the mouth of Deep Creek, 8 miles northwest 

of Spokane, and Mica, about 12 miles southeast of 

the city, the vertical range of exposures, as already 

mentioned on page 4, is about 800 fBet. Several 

wells, about which conflicting stories are current and 

much misinformation exists, were drilled in a vairi 

search for oil near the intersection of Twenty-ninth 

Avenue and Southeast Boulevard. Information obtained by Mr. · Henry Fair during the period of drilling indicates. that one well reached a depth of 1,400 

feet and penetrated 264 feet of basalt and 286 feet of 

clay and shale of the Latah formation before entering 

s. 

Btl MANI~~ PRAIRIE 

R1m.rock basalt flows 

the Latah Creek dam site, permits the mapping of the 

formation in this valley with entire confidence. In 

the valleys of Spokane and Little Spokane rivers the 

underlying formations are masked by glacial gravel, 

but doubtless the Latah formation is close to the surface in a number of places, where it may be later 

uncovered by excavations, as it has been in the clay 

pits south of Vera. 

The Latah formation extends up La tali Creek about 

10 miles to Duncan, where a ridge of granite and other 

rocks is exposed by the erosion· of the valley. This 

ridge, as described on page 10, extends from Silver 

FIVEMILE PRAIRIE" 

uRim .rod' basalt Soil and till flows 

·;;; 

f'--L-1 .L...I ..1...1 .J...I ...l...? ___ ..;.L_ __ z.J...I ---J.~------'1 MILES 

FIGURE 3.-Geologic cross section from Manito Priaire though Fiveinile Prairie to ridge north of Little Spokane River, Wash., along line 

B-B', Plate I 

the underlying rocks. This well is on Manito Prairie 

at a point about 400 feet higher than the collar of the 

Davenport Hotel well. It shows that the pre-Latah 

surface rises rapidly toward the eastern hills (fig. 3), 

a condition also indicated by other field evidence. 

lt is evident from the foregoing considerations that 

the Latah formation attains a considerable thickness:, 

but in Pleasant Prairie, Greenbluff Prairie, and other 

localities the formation decreases in thickness to the 

vanishing point in the direction of the hills that 

existed at the time of deposition, and there the overlying basalt flows rest directly on the granite gneiss. 

Hill, east of Latah Creek, west through Browns Butte 

and the hills nprth of Cheney to a point beyond 

Medical Lake. (See Pl. I.) South of the ridge Latah 

Creek has cut its valley wholly in basalt, of which 

nearly 500 feet is exposed {Pl. III, 13). The Hinch 

well, near Mount Hope, east of the creek, in the. SW. U 

sec. 14, T. 22 N., R. 44 E., penetrates ·53 feet of soil, 

271 feet of basalt, 20 feet of shale, 572 feet of basalt 

with streaks of clay, sand, and gravel, and 530 feet 

of shale and sand. Entirely different conditions of 

deposition from those near Spokane are indicated by 

this log. The overlying lavas are 843 feet thick and 
10 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

~re divided into ·upper and lower portions by 20 feet 

of shale. The 530 feet of shale and sand at the bottom 

of the well, if considered as equivalent to the Latah, 

must represent only the lower part. 

· The well of the State Normal School at Cheney is 

also south of the ridge. Below 32 feet of gra~el and 

clay, doubtless of Pleistocene age, the well penetrates 

·basalt for 4 70 feet. Clay beds from 6 to 12 inches 

thick and zo:p.es of vesicular lava separate this 470 feet 

of basalt into not less than seven distinct lava flows. I 

The deep well at the Hazelwood farm lies 7 miles 

west of Spokane, 4 miles west of the edge of the 

plateau, and several miles north of the Silver Hill-

·Cheney ridge. As reported in the log, the well is 1,135 

feet deep and passes through 12 feet of glacial till, 

159 feet of basalt, 20 feet of shale, 200 feet of basalt, 

67 feet of shale, and 230 feet of basalt, ·below which . 

shale and sand continue to the bottom, wher~ the well 

ended in "coarse sand and white crystals." ·This 

material may be the decomposed top of the ··under- . 

lying granite gneiss. So little information is given b'y 

the log that the two thick beds of basalt below the 

"rim rock" may be interpreted either as flows or as 

sills .. However, a shallow well in the same loeality has 

a more perfect log from which it is evident that the first 

of the two lower basalts consists of alternating hard 

and soft layers. The description by the driller is 

similar to that of the upper or "rim rock" basalt. If 

the log of the shallower well is used· to interpret the 

log of the deeper, it appears that 4 miles west of the 

edge of the plateau the Latah formation is interbedded with lava flows, and this interpretation has 

been used in drawing the cross section of Figur~ 2. 

This locality is on the Spokane side of the buried 

ridge, and therefore the interbedding of lava and 

sediments i$ exceptional. It may be explained as 

caused by a low gap at one point in the . protecting 

ridge which permitted . flows earlier than the "rim 

rock" to enter and overspread a small part of the 

Spokane area. These early flows must have constituted 

the dams against which the upper beds of the Latah 

formation accumulated, the locations of these dams 

being somewhere along the drainage outlet of the 

Spokane area at that time and beyond the limits of 

the region here considered. 

Farther west the lavas are more continuous and 

there is less intervening shale. At ~alouse Falls, 

70 miles southwest of Spokane, a well 951 feet deep, 

as reported by the driller, passed .through 59 feet of 

soil_, sand, and gravel and then through 892 . feet of 

basalt in which beds of shale spaced at uneven distances and ranging from 5 to 16 feet in thickness were 

found. In the Columbia Basin, west of the b~ried 

ridge, 1,200 to 1,500 feet of basalt without intervening 

shale is exposed. The transition between the geologic 

sections in the Spokane and Basin areas is partly 

revealed in the logs of wells at Medical Lake and 

Davenport. At Medical Lake, 13 miles southwest of 

Spokane, only 14 feet of shale can be certainly identified in the upper 465 feet .of the well for which a log 

is available. A well 503 feet deep at Davenport, 33 

miles west of Spokane, after passing through gravel 

and clay for 24 feet, went into rock that, from the log, 

is evidently a series of basalt flows. · 

PRE-LATAH SUR.FACE 

The Latah formation was laid down on a surface 

consisting of hills and valleys that had a relief greater 

than that of the present day. The ridges of that 

surface in part survive and project through the Latah 

formation and even through the overlying basalt. 

The Silver Hill-Browns. Butte-Cheney Hills ridge is 

the best example, but the Little Baldy ridge, north 

of Spokane, is equally conspicuous. In general, however, the small ridges were . more or less completely 

buried. . ~he later valleys have been excavated along 

. new lines, and a number of these older ridges have been 

exposed (Pl. II, A). Where the present valleys cross 

these ridges they are relatively narrow and steep. 

At the Deep Creek and Deadman Creek dam sites, 

north of Spokane,. pre-Latah ridges are exposed. 

Other ridges are entirely buried beneath the Latah 

and the overlying basalt. 

The 'surface on which the Latah formation was laid 

down had been subjected to weathering for a considerable time. As· shown in outcrops and more particularly in the drill holes ·that pass through· the 

Latah formation, put down on Dry Creek and Deadman Creek in the course of the Columbia Basin 

investigation, the granite gneiss is much decomposed 

on _the contact. : The rock is soft and shattered, and 

the feldspar is decomposed into kaolin. Evidently 

the climate of the time just preceding the Latah 

deposition was more humid than at present and resembled that of Latah time, when sequoias, oaks, 

maples, and similar trees grew abundantly. 

BASALT GROUP 

DESIGNATION 

Under the older usage all the basalts that underlie 

the great plateaus of the Columbia region were known 

collectively as the Columbia River basalt. This term, 

as defined by Russell,8 included all of the series, .from 

1,200 to 1,500 feet in thickness, that occupies the 

central region of Columbia Basin, as well as several 

groups .of flows in the foothills of the Cascade Mountains from Yakima to Wenatchee. It was shown 

by Smith,9 however, that in the region northwest of 

Ellensburg Eocene sandstone and shale are interbedded with the .lower flows. The Columbia River 

basalt obviously required subdivision; the name 

s Russell, I. C., A geological reconnaissance in centr~ Washington: U. S. Geol. 

Survey Bull. 108, pp. 20-22, 1893. • · 

g Smith, G. 0., op. cit., pp. 1-4. 
GEOLOGY OF THE LATAH FORMATION' 11 

Columbia, moreover, was preoccupied. The basalt 

flows that overlie the late · Eocene beds and were 

overlain by the Ellensburg formation, of Miocene age, 

were accordingly named by Smith the Yakima basalt. 

Since that time all the basalts of the Columbia Plateau 

have generally been correlated with the Yakima 

basalt, of supposed Miocene .age. As pointed out on 

page 12 the recent studies of the Latah formation cause 

this correlation to be modified so far as the Spokane 

area is concerned. Doubt has also been cast upon 

the general correlation in the neighborhood of Pasco 

by the work of Merriam and Buwalda.10 It therefore 

seems best at present to consider the basalts under 

a general term, and to subdivide them into local 

groups without attempting to assign formation names. 

FLOWS OF THE "RIM ROCK" 

In the neighborhood of Spokane the Columbia 

Plateau is underlain by two or perhaps three basalt 

flows that aggregate at least 200 feet in thickness. 

These flows rest upon the horizontal upper surface 

of the Latah formation at an altitude of about 2,200 

feet. Within the limits of their thickness they 

submerge the older rocks that project above this level. 

As a rule the outcropping edges -of these flows form 

the prominent dark vertical cliffs Md crags that surmount the slopes leading up to the pJateau. The 

conspicuous cliff known as the "rim rock, " which forms 

the edge of the plateau southwest of Fort Wright, 

though it does not ;measure their entire thickhess, 

fairly represents them and affords them a convenient 

name. 

The "rim rock" flows show a pronounced vertical 

jointing that causes them to separate readily into 

the five or six sided columns that. decorate nearly 

every cliff-like exposure. Particularly fine columns 

2 or 3 feet in diameter are to be seen in the cut on 

the Sunset Highway just west of Dead Man's Curve 

(PL IV, B) and in the quarry of the Washington 

Water Power Co. near by. Within the area immediately 

adjacent to Spokane this j9inting appears to be more 

characteristic of the "rim ·rock" flows than of the 

"valley" flows described farther on and thus in a 

measure serves to distinguish them. In a few localities 

shattered material witli large "pillows" occurs, but 

rock of this type is not so abundant as in the "valley" 

flows (p. 14). 

Vesicles, or gas holes, which are common at the top 

and bottom of the flows, are in natural exposures 

empty or contain a little iron· rust or calcium carbonate. In a road cut and quarry near the corner of 

Twenty-ninth A venue and Southwest Boulevard, 

Spokane, aragonite in slender clear crystals and 

sphaerosiderite occur in the v~sicles. In a qu~rry 

on . the southeast face of Fivemile Prairie the vesicles 

1° Merriam, J. C., and Buwalda, J.P., Age of strata referred to the Ellensburg 

formation in the White Bluffs of the Columbia River: California Univ. ·Dept. 

Geology Bull., vol. 10, pp. 255-266, 1917 . . 

are large and shaped ' much like a collapsed tennis 

ball. There sphaerosiderite and calcite occur. Limon 

ite replacing sphaerosiderite is common in most 

localities. It has been found in association with green 

and brown opal 10 miles south of Spokane on the 

Palouse Highway, on Pleasant Prairie, and at the 

nor.th edge of Fivemile Prairie. · 

Representative specimens of the "rim rock)' flows 

from four different localities-the southwest edge of 

Fivemile Prairie, the plateau half a mile west of Fort 

'\Vright, Biglow Gulch east of Hillyard, and the 

quarry of the Washington Water Power Do. south 

of Dead Man's Curve on the Sunset· Highway-are 

all basalts consisting essentially of plagioclase feldspar · 

and pyroxene with subordinate olivine and more or 

less glass. As determined by F. C. Calkins, 

Most of these contain at least a few small roundish blowholes, and all contain small irregular pores from the walls of 

which crystals of feldspar project. All appear well crystaUized. 

Under the microscope it is seen that all contain a moderate 

amount of olivine. The augite forms interstitial granules or 

larger individuals inclosing or molded upon the laths of plagioclase. A good deal of brown: glass, crowded with particles of 

iron ore and with other microlites, is present in all specimens. 

Flows correlated with those of the "rim rock" form 

cliffs at the same level on the opposite side· of the 

valley, at the edges of Fivemile Prairie and the other 

plateau remnants along Little Spokane River, on 

the west side of the Latah Creek valley, and elsewhere, 

as shown on the geologic ;map (Pl. I). Before these 

valleys were cut the flows must have extended· continuously across the area. Within the limits -indicated the flows appear to be horizontal and to be 

confined to altitudes between · 2,200 and 2,400 feet. 

East and southeast of Spokane, however, basalt that 

is apparently the same as the "rim rock" flows occurs 

at higher levels. Near ·Mica it reaches an altitude 

of 2,600 feet but its base is not exposed. In the , 

neighborhood of Coeur d'Alene it occurs between the 

2,300 and 2,500 foot levels. Possibly this difference 

in height is to be explained as a result of a later slight 

elevation of the earth's crust toward the southeast, 

an idea that is supported by the fact that in several 

places in the Columbia Plateau outside of the Spokane 

area the lava is moderately deformed . . 

This basalt is thought to have risen through fissures 

to the surface, where it spread out in _the form of 

sheets. For the reason that no adequate vents are 

known outside the borders of the plateau, the bulk 

of the lava is thought to have come from fissrires 

within its area and therefore to the south and southwest of Spokane. Presumably the . dikes exposed in 

the railway cuts west of Latah Creek described on 

page 12 represent vents through which a small part 

of the lava composing the "'rim rock" flows reached 

.the surface. The bulk of the lava, however, must 

have risen through larger · fissures situated farther 

southwest. 
12 SHORTER CONTIDBUTIONS TO GENERAL GEOLOGY, 1925 

The flows of "rim rock" lie upon the beds of the 

Latah formation and show no angualr discordance 

with them. The contact can be observed in only one 

locality, a road cut on Pleasant Prairie · near the line 

between sees. 29 and 30, T. 24 N., R. 44 E. At this 

place, as shown in Plate IV, 0, the much weathered 

basalt rests on a black soil zone from 2 to 4 inGhes 

thick containing lignitized twigs and other vegetable 

litter. Below the soil the Latah shale, easily identified 

by scattering and imperfect plant remains, is weathered 

and iron stained for 2 to 3 feet. The contact is 

slightly uneven but does not give any definite indication of erosion of the shale. Apparently the soft beds 

of the Latah . formation had been exposed to erosion 

only long enough to produce slight irregularities in 

the surface and a soil zone before the' lava covered 

them. The conclusion seems to be that the ~o)Vs of 

the "rim rock" are but little younger than the Latah 

formation. 

The "rim rock" flows of the Spokane area form a 

definite group, but a thicker series of basalt flows 

underlies the plateau to the south and west of this 

area. On the surface the "rim rock" flows appear to 

be continuous with the top flows. of this thicker series. 

In the Hazelwood well the lower flows are thought to 

belong to the thicker series . 

. In the Ellensburg quadrangle, about 150 miles westsouthwest of Spokane, the geologic section 11 includes, 

in ascending order, the Yakima basalt, Ellensburg 

formation, and Wenas basalt. The Yakima basalt 

submerges an uneven surface of older rocks and consists of many flows piled one on the top of another to 

a thickness · of· 2,000 feet or more. The overlying 

Ellensburg is composed of sediments having a total 

thickness of as much as 1,600 feet. The Wenas basalt 

comprises two or three flows of rather small extent that 

· range from a few feet to 200 feet in aggregate thickness. It overlies the Yakima basalt, from which it is 

separated by Ellensburg sediments ranging from 84 to 

135 feet in thickness. The bulk of the Ellensburg 

beds lie above it. 

In the general vicinity of Yakima the Ellensburg 

formation overlies the Yakima basalt, whlch is generally regarded as equivalent to the bulk of the basalt 

of the Columbia Plateau. Likewise the ·Mascall overlies the main body of basalt in central Oregon, which 

also is regarded as a part of the basalt of the Columbia 

Plateau. In the Spokane area no flows were found in 

a position corresponding to the Yakima basalt, namely, 

beneath sediments corresponding to the Ellensburg, 

or in other words, the Latah. The "rim rock" flows, 

which overlie the Latah, are therefore later than the 

Yakima basalt. However, there is nothing to suggest 

that they are much later. 

The area north of Spokane River ~nd west of the 

valley of Little Spokane River shown o~ the geologic 

11 Smith, G. 0., op. cit. 

map (Pl. I) has not been examined in detail by (,he 

writers. The geology has been generalized from the 

excellent map of Weaver,12 and his Camas basalt has 

been considered equivaleil.t to the flows of the "rim 

rock." For this correlation the only evidence is that 

the Camas basalt of Weaver is also olivine bearing, 

attains similar altitudes, and consists of small patches 

that appear to be outliers of the Columbia Plateau. 

BASALT SILLS AND DIKES 

The Latah formation has been intruded by igneous 

rocks, as may be observed at intervals along the slope 

west of Latah Creek from S., P. & S. cut No. 1 and 

Milwaukee cut No. 1 southward and also in the 

slopes of several of the "prairies" north of Spokane 

and elsewhere. . 

In the railway cuts of the Latah Creek valley three 

dikes from 2 to 10 feet wide and several dik~s merging 

int,o sills are exposed. The type of dike is shown in 

Plate V, A, the base of one of the sills in Plate V, B, 

and the end of another in Plate V, 0. The rock in 

both dikes and sills is a fine-grained dense blue-gray 

basalt similar in hand specimen to the overlying 

basalt of the "rim rock." The similarity in mineral 

composition, particularly in the presence of olivine, as 

shown below, between the rock of the dikes and that 

of the "rim rock" flows lends support to the supposition that the dikes were feeders in the eruption of 

the flows. Both the dikes and the sills have a finegrained or glassy exterior where they cooled quickly 

in contact with inclosing shale. The grain of the 

interior is fine in small bodies and becomes coarser in 

the central parts of large bodies. Near the contact 

the shale is slightly hardened and changed in color. 

This influence on the shale extends from 6 inches to 

io feet. Beyond this zone the shale is entirely 

unchanged. 

Specimens representing three of these intru~ive 

bodies exposed in the railway cuts west of Latah Creek 

are described by Mr. Calkins as follows: 

Specimens taken several feet· from contacts either are quite 

compact or contain only minute irregular pores not readily 

visible without the aid of a hand lens. The textures are 

mode~ately fine and might be taken for holocrystalline. Under 

the microscope, however, a little residual glass is found in even 

the most crystalline specimen (No. 10), taken from the middle 

of a 40-foot sill. Except for the presence of this glass, the 

texture of the specimen is typically ophitic. The most abundant constituents in all are of course plagioclase and augite; 

and olivine, though subordinate to plagioclase and augite, 

is present in all the specimens having a crystalline appearance 

but No. 7. This specimen is further remarkable in containing 

uniformly scattered grains of siderite which shows no evidence 

of being secondary; . I regard it as having been the last original 

constituent to form. 

Two specimens from the 'margins of a sill and a dike have a· 

wavy surface and a . visibly glassy selvage about half an inch 

thick. A thin section from the selvage shows plagiocla3e laths 

· as the only identifiable crystals in a cloudy glass base. 

u Weaver, C. E., op. cit., pp. 99-101. 
U . S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE II 

A. PLEASANT PRAIRIE, WASH. 

B. LATAH CREEK VALLEY AND THE COLUMBIA PLATEAU, WASH. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE III 

A. LATAH FORMATION AND FOSSIL LOCALITY OF DEEP CREEK CANYON, WASH. 

B. EAST SIDE OF LATAH CREEK VALLEY SOUTH OF DUNCAN, WASH. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE IV 

A. "RIM ROCK" FLOWS, SUNSET HIGHWAY WEST OF SPOKANE, WASH. 

B. DETAIL OF COLUMNAR JOINTING IN CUT ON SUNSET HIGHWAY 

C. CONTACT OF ~'RIM ROCK" FLOWS ON LATAH FORMATION ON PLEASANT PRAIRIE, WASH. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE V 

A. BASALT DIKE INTRUDED INTO SHALE, S., P. & S. CUT NO.4, SPOKANE, WASH. 

B. LOWER CONTACT OF BASALT SILL WITH SHALE, MILWAUKEE CUT NO.1, SPOKANE, WASH. 

C. END OF BASALT SILL, SPOKANE, WASH. 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE VI 

A. "THE CLIFF," NEAR MILAN, WASH 

B. VALLEY FLOWS ON LEFT BANK OF SPOKANE RIVER NEAR SEVENMILE, WASH. 
U. S. GEOI,OGICAL SUH.VEY 

A. BASALT CLIFFS AT MOUTH OF CREEK 

PROFESSIO NAl , PAPEH. 140 PLATE VII 

B. "PILLOW" STRUCTUR'_E IN THE VALLEY FLOWS OF THE CANYON 

VIEWS ON DEEP CREEK, \V ASH. 

C. DEVILS TOP 

Photograph by William Donahue 
GEOLOGY OF THE LATAH FORMA'.riON 13 

The dikes arose along joint planes 3tnd caused no 

disturbance of the shale, but the sills have wedged 

themselves between beds and have. broken and 

crumpled the shale for distances of 50 to 100 feet. 

In the Latah Creek valley the number of sills is 

large. Most of them were intruded at altitudes 

between 1,800 and 2,000 feet. Many are 25 to 50 feet 

thick and from 300 to 500 feet long. All that could 

be observed end abruptly. The lower sill shown in 

the cross section of Figure 2 is at least 100 feet thick, 

and it crops out along the valley for about half a mile. 

The sill on the west abutment of the Latah Creek 

dam site (Pl. II, B) is more than 250 feet thick, yet, 

as was brought out in striking fashion during drilling operations at this place, it ends abruptly on 

the east. 

Basalt sills are co:rrunon features of the slopes developed on the Latah formation in all the "prairies" 

north of Spokane. These sills are irregular in position, thickness, and length, and their out'crops are in 

many places more or less concealed by soil or glacial 

till. A few of the more prominent sills are represented 

on Plate I. · 

Because the sills intruded in the Latah formation 

lie approximately horizontal, there is some difficulty 

in distinguishing in the field the outcrops of such 

bodies from those of interbedded lava flows. The 

niineral composition and texture of the two, so far as 

can be seen by the unaided eye, are almost identical. 

But the sills cooled under cover and under pressure 

and therefore, except for the thin glassy crust, which 

is seldom seen except in artificial exposures, they are 

massive and free from scoriaceous and vesicular 

portions. Near the margin some sills have small 

scattered g~s holes. The flows, however, owing to 

the expansion of gases expelled from the lava during 

cooling, have scoriaceous and vesicular layers at the 

top and usually similar layers at the bottom. Some 

of the sills have well-marked columnar jointing, the 

joints being tight and the columns large and regular, 

but as a rule jointing is not well marked in these 

bodies. Generally the flows show a jointing that is 

variable or irregular but usually open and conspicuous. 

The lnost useful criterion is perhaps the discontinuity- of the sills. Interbedded flows would have 

more or less continuous outcrops at the same altitude 

for long distances. The end of a flow, moreover, is 

marked by a characteristic rubble or by scoriaceous 

material or, as in the "valley" flows described in the 

next section, by "pillow" structure. 

FLOWS IN THE VALLEYS 

The basal~ flows that underlie the city of Spokane 

and cause Spokane Falls occur, so far as now known, 

only in valleys eroded in the "rim rock" flows and 

the Latah formation. 

In the city of Spokane, along the gorge of Spokane 

River, and in the valleys of Latah Creek, Deep Creek~ 

85658°-26--2 

and Little Spokane River the slope below the ''rim 

rock" exhibits , cliffs and other rugged outcrops of 

basalt that, in one place or another, include parts of 

all the flows of a complete series built up from the 

bottom. In general the areas in which these lavas 

crop out are small, but on the geologic map (Pl. I) 

a large area is shown west of the valley of Little 

Spokane River near Deer Park. This area was not 

examined in detail. It is generally flat and has an 

altitude of about 2,000 feet, or about that of the :most 

prominent glacial terrace (p. 15). Half Moon Prairie 

is underlain by basalt, and so also are large areas 

southeast of Deer Park. The cover of gravel belonging to the terrace makes mapping a long and tedious 

task and makes the identification of the basalt with 

the younger series uncertain. The inclusion of this area 

with the area of "valley" flows must ·be considered 

tentative. 

The highest of these" valley" flows reaches an altitude a little greater .than 2,100 feet. It forms the 

cliff at the falls in Indian Canyon and low cliffs near 

the head of the small valley tributary to Latah Creek 

north of S., P. & S. cut No. 1. Large loose masses of 

basalt on the slope above this cut, in Spokane at 

Cannon Hill and elsewhere, probably are remnants of 

this flow. At Ash and Fairview streets, in t~e northwestern part of Spokane, and at places down Spokane 

River there are remnants of a flow at an altitude of 

about 2,000 feet. At the next lower level is the thiek 

mass of basalt composed of two or three separate flows 

across which Spokane River descends in the famous 

. cataract of Spokane Falls. 

The base of the ''valley" flows at Spokane is located 

by the well at the Davenport Hotel (p.-9 and fig. 3). 

Farther north, however, it may be lower. If the 

bottom of the lava in the Davenport Hotel well is the 

maximum depth, the valley eroded in the "rim rock" 

flows and the Latah formation had a depth of at 

least 880 feet· at Spokane. The erosion of this valley 

must have required considerable time. It is a measure 

of the difference in age of the "valley" and "rim 

rock'' flows. 

Contacts between the "valley" flows and the Latah 

formation have been observed by the writers in only 

three places. At Deep Creek, in 1922, the basalt 

could be observed resting against a slope covered by 

5 feet of rubble and soil, which in turn rested on the 

shale of the Latah · formation. This contact was 

buried as a result of the spring floods in 1923. ln a 

cut . on the Spokane, Portland · & Seattle Railway in 

the western outskirts of Spokane, near Fort Wright, 

the contact of the lavas on the . Latah is well 

exposed. The contact has irregularities of 5 . to 1 Q 

feet, but the general slope is to the north and east. 

Much of the lava at this place is a breccia or rubble 

of broken material and "pillows." The higher parts 

of each flow and the higher flows extend farther to 

the south and west. It is evident that the lava was 
14 SHORTER . CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

extruded in an ancient valley and that each succeeding 

flow rose higher against the hill slope. At Twelfth 

A venue and Thor Street, Spokane, the street cut 

exposes a similar contact. Here a single bed of fragmented lava anfl "pillows" rests with a very irregular 

contact on shale with fossil leaves of the Latah 

formation. 

R ussell/3 in 1896, observed the contact in a cut 

made in grading for the street-car line where it turns 

east from Barnard Street on Eighth A venue. This 

exposure is no longer visible, but as described by 

Russell and shown in his sketch the basalt rested on 

the shale with an uneven contact. Gravel and sand 

resting on micaceous clay, together with detached 

masses of the clay, extended upward into the inequalities of the under surface of the basalt. Russell 

believed that this basalt flow moved from west to 

east into a shallow lake, the bottom of which was disturbed and forced up into the ridges described above. 

The lowest exposure of the ''valley" flows is at the 

canyon of Deep Creek on Spokane River, at an altitude of about 1,650 feet. The higher flows reach an 

altitude of 2,100 feet in several localities in the eastern 

outskirts of Spokane and also near Mead and near 

Milan. These facts indicate a thickness for the flows 

of 450 feet. However, the well of the Davenport 

Hotel, after penetrating 60 feet of sand and gravel, 

passed through 370 feet of basalt, the base of the 

flows in this well being therefore at an altitude of 

about 1,520 feet. The difference between this altitude 

and 2,100 feet is 580 feet, which may be taken as the 

maximum known thickness. 

These flows are generally massive and thick. Commonly they are separated into small irregular blocks 

by shrinkage cracks that cut them in different directions. They contrast with the older basalt in their 

general lfl,ck of vesicles and frothy lava. So far as 

observed they do not show a columnar jointing comparable to that of the flows composing the" rim rock." 

Small irregular columns occur, ·but large regular 

columnar jointing is rare. Locally the rock at Spokane 

Falls breaks into columns, but the columns are curved 

and comparatively small, and they stand at various 

angles. It is thought that the lack of regularity is 

due largely to the fact that the exposures most comnwnly observed in the vicinity of Spokane are near 

the margin of the flows, for in" The Cliff," a small remnant near Milan, columnar jointing is well developed 

(Pl. VI, A). A characteristic feature of . the valley 

flows is a tendency to weather along widely spaced 

joints into columns, rounded pinnacles, and other 

forms, som.e of which assume an odd or fantastic 

appearance (Pis. VI, B, and VII, A). At· the mouth 

of Deep Creek there is an unusually fine display of 

these huge masses loosened from their parent ledges 

and tumbled together in grand confusion (Pl. VII, 0). 

1a Russell, I. 0 .• U.S. Geol. Survey Water-Supply Paper 4, pp. 52-54, 1897. 

Apparently they are the result of weathering along two 

or more sets of widely spaced joints. 

The· basalt is generally a fine-grained gray or black 

rock, but there is some variation between flows. 

Beds of a peculiar breccia occur along the margin of 

the basalt where it rests against the Latah formation. 

In this material, like plums in a pudding, are rounded 

masses of basalt from 1 to 6 feet in diameter (Pl. 

VII, B). They have a glassy outside c.oating from a 

quarter to half an inch thick and dense or vesicular 

interiors. These masses are of the typ~ known as 

''pillows" and evidently broke free from the advancing 

flows as big drops of liquid lava. The exteriors 

cooled suddenly and therefore are glass, but the 

interiors cooled more slowly and are largely crystalline. 

In most of the masses the gases contained in the 

molten lava separated as bubbles, forming .the vesicular 

and scoriaceous interior. "Pillow" structure in 

lava is usually attributed to extrusion of the lava 

into or under waterY The general presence of lava 

of this type near contacts and the change from solid 

sheets of basalt to "pillow" lava may be considered 

part of the evidence that the basalt of tR.e younger 

series was extruded in valleys where the advancing 

flows moved into temporary water bodie$ near the 

sides of the valleys. 

In the summer of 1924 Edward Sampson visited 

Deep Creek, and he has furnished the following account 

of the unique basalt breccia associated with the 

"pillow" lava. 

The pillow lava is displayed in great perfection on the eas\ 

side of the Deep Creek canyon. Ib some places individual 

pillows, as is common in such lava, fit over the irregularities 

of those beneath, so that there is very little space betweel}. them. 

In other places the pillows are not closely packed but form only 

about half the total mass, and a few pillows are apparently 

wholly detached and surrounded by fragmental rock or 

breccia. This breccia is a loosely coherent mass of rough 

fragments averaging about a quarter of an inch across. The 

color is generally gray but in places is buff to yellow. 

Through the skill of C. S. Ross, both polished and thin 

sections were prepared by impregnation with a balsam-kololith 

mixture and with bakelite. Microscopic study of these sections 

shows that the fragments of the breccia are composed of basalt 

glass containing a few phenocrysts of plagioclase and a much 

less number of augite grains. Almost every fragment contains 

one or more vesicles through which the boundaries of the fragments pass at random. Obviously the fragments have been 

formed by the disruption of a glass that was already vesicular. 

Most of the fragments bear no oriented relation to adjacent 

fragments, but a few show only slight displacement from their 

neighbors. 

The fragments of the brown or buff rock are surrounded by a 

thin shell of material of unknown composition. In thin sections 

it is orange-colored and contrasts with the glass, which is dark 

brown. Part of the shell is moderately birefringent, and part 

appears isotropic, but the isotropism may be due to an extreme 

fineness of grain in an anisotropic substance. It seems unquestionable that the shell is formed by the alteration of the glass 

of the fragments, as feldspar laths project from unaltered glass 

into the yellow crust. 

H Russell, I. 0., Geology and water resources of the Snake River Plains of Idaho: 

U.S. Geol. Suryve Bull. 199. pp. 113-117, 1902. 
GEOLOGY OF THE LATAH FOE,MATION 15 

In the spaces between the fragments is a substance which 

from its optical properties is probably halloysite (Ab03.2Si02. 

nH20) or allophane (Al20a.Si02.nH20). It is gray to cream-col.: 

ored, very soft and cheesy, with a hardness of about 3 in the 

Mohs scale. In thin section the mineral is opaque, but when 

crushed to a size passing a 200-mesh screen it is transparent. 

Such pieces are dark brown, perhaps owing to included air, 

but 24 hours' immersion in oil did not appreciably change the 

color. The mineral appears to be perfectly isotropic and has 

an index ranging from 1.46 to 1.47, owing to lack of uniformity. 

According to Larsen's tables, the properties recounted above 

are common to the minerals halloysite and allophane. The 

mineral does not completely fill the interstices, and it also has 

relatively wide cracks within its mass. Thus it appears to have 

shrunk in volume as if through the dehydration of a gel. 

The present writer believes the view fairly well established 

that pillow lavas have formed by lava flowing into, over, or 

under water. It seems not improbable that the associated 

breccia has formed by the disruption of a basalt flow thr:ough 

the violent physical reaction of highly heated lava and water. 

Gas released from within the lava may have aided in this disruption, as indicated by the large number of vesicles. 

From collections made by Mr. Henry• Fair, Shannon 15 has identified a long list of minerals obtained 

from the vesicles in this basalt. The principal species 

are ~ristobalite, black bpal, hyalite, and sphaerosiderite. The sphaerosiderite occurs as an incrustation 

similar to that fo~d in the flows of the "rim rock," 

and also as hemispheres from a quarter to half an inch 

in diameter that are secondary and later in origin. 

Limonite and goethite replacing the sphaerosiderate 

are found. 

At Deep Creek, 8 miles northwest of Spokane, black 

opal, opal and chalcedony replacing aragonite, and 

hyalite are present in cracks in ''pillow" lava. Sphaerosiderite occurs alone in small gas holes of the basalt 

in a quarry near Milan. The minerals found in the 

younger flows all occur in artificial exposures except 

at the Deep Creek locality. 

Specimens of the "valley" flows from the foot of 

Spokane Falls, the cut on Division Street, and the 

mouth of Deep Creek were examined by Mr. Calkins, 

who says: 

They show to the unaJded eye no consistent difference from 

the "rim rock" flows, though they are perhaps a little duller 

and more bluish. The blow holes in No. 15 (the specimen from 

Division Street) are almost wholly filled with hard iron oxide 

(goethite?). Their appearance under the microscope is highly 

characteristic. All are without olivine, which occurs in all the 

"rim rock" specimens; and the augite occurs in splintery or 

prismatic forms and seems to be nearly contemporaneous with 

the plagioclase, instead o(distinctly later, as in the "rim rock" 

lava. These later flows are probably less magnesian than the 

older. 

So far as positive evidence goes the flows in the 

valleys may be as young as early Pleistocene. Probably, however, they belong to the same period of 

volcanism that produced Columbia Plateau and other 

igneous features in the Northwest that are thought 

generally to belong within the Tertiary. 

15 Shannon, E. V., On siderite and associated minerals from the Columbia River 

basalt at Spokane, Wash.: U. S. Nat. Mus. Proc., vol. 62, pp. 1-19, 1923. 

GRAVEL GROUP 

Large deposits of unconsolidated or loosely coherent 

gravel occur in Spokane Valley and the · valleys of 

Latah Creek and other streams. These deposits lie 

upon the eroded surface of the rocks previously 

described and are mostly of glacial origin. In the 

valley of Latah Creek and in that of Lake Creek near 

Marshall are large terraces at an altitude of about 

2,300- feet -built of gravel that contains much basalt 

and here and there a boulder of the fossiliferous shale. 

This gravel was deposited during a comparatively 

early Pleistocene stage of glaciation, described by 

Bretz 16 as the Spokane glaciation. · The ice advanced 

from the north, crossing Fivemile Prairie, Pleasant 

Prairie, and ·other areas, from which it plucked masses 

of basalt and shale. ~ 

The floor of Spokane Valley and the extensive 

terraces along the river below Spokane up to an 

altitude of 2,000 feet are composed chiefly of graveL 

derived from granite and metamorphic rocks. This 

deposit is later than the other. Traced eastward it 

leads to a moraine at the south end of Pend Oreille 

Lake. Evidently it is outwash from a glacier that at 

a late stage, presumably Wisconsin, occupied the 

basin of that lake. 

Both the older and younger members of the gravel 

group lie upon surfaces eroded across the valley 

flows. Evidently they were not deposited until after 

the greater part of these flows-all except the present 

remnants_:_had been cleared from the valleys. -~-

SUMMARY OF THE GEOLOGIC msTORY 

The events of geologic time prior to the Tertiary 

period have left a record in the Spokane area only in 

the rocks of the granite-schist group. The story, 

doubtless much obscured, has not yet been deciphered, 

and so far as the events recorded in the rocks described 

in this paper are concerned the pre-Tertiary history 

is a closed chapter. The recital begins anew with the 

form of the pre-Latah surface, which indicates that by 

Miocene time the area was a mountainous land. 

Hills and mountains greater than those of to-day extended westward beyond Spokane, where now lie the 

relatively smooth plains of the Columbia Plateau. 

This mountainous region was doubtless wooded and 

well watered, for, wherever found, the ancient surface 

is composed of deeply weathered rock. 

With the beginning of volcanism and the outpouring of basalt to the south and west, the drainage of 

the area became obstructed. In the ponded stream 

channels debris stripped from the mountains and 

· dropped from the air as ash showers resulting from 

the explosions of distant volcanoes accumulated in 

the form of extensive sheets of gravel, sand, and clay. 

As basalt was built up sheet by sheet and as one lava 

16 Bretz, J. H ., Glacial drainage on the ColUiilbia Plateau: Geol. Soc. America 

Bull., vol. 34, pp. 573-£08, 1923. ' 
16 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

flow followed another, the Columbia Plateau was 

- constructed. The flows, moving northeastward, extended farther with each successive outpouring and 

buried much of the old rugged highland, entering 

valleys, swinging around headlands, and completely 

surrounding isolated hills. Against this flood of lava 

the Silver Hill-Cheney Hills ridge and the doubtless 

more isolated hills to the west and north formed a 

barrier that almost wholly prevented the entrance of 

the molten lava into the Spokane area. 

Behind this encircling ridge the streams poured 

sediment into quiet ponds, sh~llow swamps, and 

slowly-moving channels. Here the Latah formation 

was gradually built to a maximum thickness of 1,500 

feet, and here were entombed iri the clay the leaves, 

fruits, and twigs of the plants that grew in the area and 

also some remains of those . that occupied higher 

ground. 

Twice this area was partly invaded by lavas, as 

indicated by the record-'of the Hazelwood well, before 

it was finally overwhelmed by the flows of the "rim 

rock." When in this catastrophe the encircling ridge 

was overtopped the lavas not only covered the plain 

of alluviation but exteTJ.ded beyond it onto the lower 

slopes of the· bordering mountains. These flows were 

fed from the west, but in addition there were local 

vents from which molten rock welled up from below 

through the Latah formation to augment the volume 

of the overlying lava. 

After the invasion of the "rim rock" flows valleys 

deeper than those of to-day were cut in the basalt and 

the underlying shales of the Latah formation. Here 

new outpourings of basalt built up a plain nearly to 

the height of the "rim rock" flows. 

Again the streams cut through these flows to a level 

below that of the present. Next they,were obstructed 

by glacial deposits, first by debris deposited directly 

by a glacier from the north and next by gravel washed 

down from a glacier at Lake Pend Oreille. Immense 

floods carried the gravel from this source down Spokane Valley, filling it at Spokane to the 2,000-foot 

level. The Spokane Falls are an indirect result of 

this last filling. After clearing its valley up to the 

falls and incidentally producing extensive gravel terraces below Spokane, the river found itself placed at 

one side of its former channel and hung up, so to , 

speak, on a ridge of basalt. · 

Thus it appears that since the old and rough sur~ 

face of the granite-schist group of rocks became 

buried beneath .the fossil-bearing shale and that 

formation w·as in turn covered by the flows of the 

"rim rock," the valleys of this area have been excavated, filled, and reexcavated, time after time. When 

Spokane River, therefore, has finally completed its 

task of reexcavating its valley, Spokane Falls, Coeur 

d'Alene Lake, and many other of -the beautiful water 

bodies that form one of the chief attractions of this 

region will have disappeared. Save then for the 

"prairies" with remnants· of leaf-bearing shale and 

their "rim rock" of basalt, the region will be largely 

restored to its condition before any of these events 

took place, and the cycle will be complete. 
• 

FLORA OF THE LATAH FORMATION OF SPOKANE, WASHINGTON, AND COEUR D'ALENE, 

IDAHO 

By F. H. KNOWLTON 

With a report on the diatom deposit by ALBERT MANN 

INTRODUCTION 

The geologic conditions under which the flora of the 

Latah formation occurs have beeri set forth at length 

in the preceding paper by J. T. Pardee and Kirk 

Bryan. Briefly summarized these conditiom.s are as 

follows: 

The area which has supplied the fossil flora herein 

described lies along the Columbia Plateau and the 

mountains of northern Idaho and northeastern Washington. It includes parts of the valleys of Spokane 

and Little Spokane rivers and adjoining parts of 

the mountains and the plateau. 

The mountainous part of the area is composed 

principally of crystalline and metamorphic rocks, such 

as granite, ·gneiss, and schist, but includes small 

masses of quartzite. The topography is very rugged. 

The city of Spokane stands at the northeast 'corner of 

the Columbia Plateau, which stretches far away to 

the south and west and owes its general character to 

the fact that it is built up of vast lava flows that 

remain nearly as flat as they were when cooled. 

The plant-bearing beds, to which the name Latah 

formation has been given by Messrs. Pardee and 

Bryan, consist mostly of shale or clay but include a 

few layers of sand and gravel. The colors o~ the beds 

range from pale yellowish gray to lead-gray or bluish 

gray, the prevailing shades being rather dull. These 

beds rest uncomformably on the granite-schist group 

and are overlain by the basalt flows. As they are 

very soft they are easily eroded and have been largely 

removed except . where protected by the basalt, and 

consequently they are of rather small areal extent. 

The maximum thickness of the Latah formation is 

approximately 1,500 feet, though this thickness can 

not be noted at any one place. 

Further details concerning the geologic and other 

relations will be found in the preceding paper. 

SPECIES INCLUDED 

As a preliminary to the consideration of! the flora 

the following complete list of the forms thus far 

identified is given: 

Archaeomnium patens E. G. Britton, n. gen. and sp. 

Polytrichites washingtonensis E. G. Brittop, n. gen. 

and sp . 

.- Moss, genus and species? 

· Fern, fragment. 

Ginkgo adiantoides (Unger) Heer. 

Equisetum, underground stem. 

Lycopodium hesperium Knowlton, n. sp. 

Tumion bonseri Knowlton, n. sp. · 

v'Pinus sp. . 

equoia langsdorfii (Brongniart) Heer. 

v Sequoia? sp. 

vTaxodium dubium (Sternberg) Heer. 

vTaxodium, male aments. 

vLibocedrus praedecurrens Knowlton, n. sp. 

Typha? sp. 

~otamogeton sp. 

Grass, leaf. 

vGrass?, genus? 

Arisaema hesperia Knowlton, n. sp. 

t/Populus heteromorpha Knowlton, n. sp. 

./Populus fairii Knowlton, n. sp. 

/ populus lindgreni Knowlton. 

Jl>opulus washingtonensis Knowlton, n. sp. 

v Salix remotidens Knowlton, n. sp. 

JSalix elongata 0. Weber. 

/ Salix perplexa Knowlton. 

,Salix inquirenda Knowlton, n. sp. 

/ Salix bryani Knowlton, n. sp. 

,/Salix day ana Knowlton. 

/ Salix sp. 

/ Alnus, cones. 

Betula fairii Knowlton, n. sp. 

L, Betula nanoides Knowlton, n. sp. 

L Betula heteromorpha Knowlton. 

J Betula thor Knowlton, n. sp. 

c Betula? largei Knowlton, n. sp. 

L Betula bryani Knowlton, n. sp. 

Qarpinus sp. 

VCastanea castaneaefolia (Unger) Knowlton. 

uercus merriami Knowlton. 

"-Quercus bonseri Knowlton, n. sp. 

uQuercus cf. Q. pseudo-lyrata Lesquereux. 

v Quercus rustii Knowlton, n. sp. 

uercus spokanensis Knowlton, n. :Sp. 

Quercus payettensis Knowlton. 

Q~ercus praenigra Knowlton, n. sp. 

/ Quercus simulata Knowlton. 

J Quercus chaneyi Knowlton, n. sp. 

uercus obtusa Knowlton, n. sp. 

J.Quercus, cup. ·. 

Quercus, acorn. 

/ Ulmus speciosa Newberry. 

vUlmus fernquisti Knowlton, n. sp, 

Ficus? washingtonensis Knowlton, n . . sp. 

_/Laurus similis Knowlton. 

Laurus princeps Heer. 

v Laurus californica Lesquereux. -

vLaurus grandis Lesquereux. · 

~ Magnolia dayana Cockerell. 

./Magnolia sp. · 

Liquidambar pachyphyllum Knowlton. 

Liquidambar, fruit. 

17 
18 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

Hydrangea bendirei ·(Ward) Knowlton. · 

Prunus rustii Knowlton, n. sp. 

Cercis? spokanensis Knowlton, n. sp. 

Sophora alexanderi Knowlton, n. sp. 

Sophora spokanensis Knowlton, n. sp. 

Robinia? sp. 

Meibomites luceris Knowlton, n. gen. and sp. 

Celastrus fernquisti Knowlton, n. sp. 

_}.thu,s typhinoides Lesquereu:x:. 

Acer bendirei Lesql,lereux. 

V.Acer merriami Knowlton. 

cer minor Knowlton. 

Acer chaneyi Knowlton, n. sp. 

~ccinium salicoides Knowlton, n. sp. 

~~ospyros anci.()rsonae Knowlton n. sp. 

Di9spyros? microcalyx Knowlton, n. sp. 

Malva? hesperia Knowlton, n. sp. 

Phyllites amplexicaulis Knowlton, n. sp. 

Phyllites crustacea Knowlton, n. sp. 

Phyllites pardeei Knowlton, n. sp. 

Phyllites sophoroides, n. sp. 

Phyllites peculiaris Knowlton, n. sp. 

Phyllites relatus Knowlton, n. sp. 

Phyllites sp. 

Carpites menthoides Knowlton, n. sp. 

Carpites boraginoides Knowlton, n. sp. 

Carpites polygonoides Knowlton, n. sp. 

Carpites spokanensis Knowlton, n. sp. 

Carpites ginkgoides Knowlton, n. sp. 

Carpites magnifica Knowlton, n. sp. 

Carpites paulownia Knowlton, n. sp. 

Branchlet and bud? 

RELATIONS OF THE FLORA 

As already set forth in detail in the geologic account 

by Messrs. Pardee and Bryan, the plants of the Spokane 

area occur in layers of clay associated with basalt 

flows. The stratigraphic relations of the plants from 

the Coeur d'Alene area are not so definitely known, 

but as a number of the species are identical with those 

of the Spokane area the age and structural relations 

are also presumably nearly identical. 

The primary object of the study of this flora was to 

ascertain its bearing on the age of the basalt flows 

·· with which the plant-bearing beds are so intimately 

associated. -· Spokane is at practically the northeastern 

limit of the great basalt flow, the so-called Columbia 

River basalt, one of the greatest bodies of lava in the 

world, which has an area of approximately 250,000 

square miles, including the greateryart of Washington, 

eastern Oregon, much of northern California, and the 

great Snake River Plain in Idaho. As the fossil plants 

obtained from the sediments associated with these 

flows afford the )llost extensive paleontologic data-for 

the determination of their age, the study of the 

present collection is of great stratigraphic value. 

Before discussing the floras from Spokane and Coeur 

d'Alene it is necessary briefly to review certain floras 

and formations with which these may be compared. 

• 

COMPARABLE FLORAS IN OTHER FpRMATIONS 

PAYETTE FORMATION 

The Payette formation, named by Lindgren/ is ,a 

series of lake-bed deposits having a :maximum thickness 

of 1,000 feet in the lower part of the Snake River valley, 

Idaho. Fossil plants were found in these beds at 

four localities. The total flora then recognized 

numbered 32 species, of which 17 were regarded as 

new to science and 5 were not named specifically, 

leaving, as then known, only 10 species having an 

outside distribution. As 6 of these 10 forms were 

regarded as identical with described species from 

Bridge Creek, Oreg., and several others as closely 

related to Bridge Creek species, it was concluded that 

the Payette formation was of the same age as . the 

beds at Bridge Creek, which were then regarded as 

upper Miocene. 

The age determination of the plant-bearing beds 

in the John Day Basin, Oreg., that was then current 

was based largely on the earlier work of Lesquereux, 

but the localities were not differentiated, all being 

grouped under the designation "John Day Basin." 

Although it was of course noted that there were 

marked differences in the matrix bearing the plants, 

the specimens were all supposed to be of approximately 

the same age-that is, upper Miocene. 

Subsequently (1900) John C. Merriam visited the 

John Day Basin and worked out in detail the stratigraphic relations of the Tertiary deposits. To the 

oldest of these deposits, a series of beds some 400 feet 

in thickness, composed of rhyolite and andesite flows 

and ash and tuff beds resting on Cretaceous rocks, 

Merriam gave the name Clarno formation. The 

Bridge Creek locality is in the extreme upper part 

of the Clarno formation and the age was con~idered 

to be upper Eocene. 

The next higher plant-bearing beds above the 

Clarno were named by Merriam the Mascall formation. 

This formation is a series of s·ediments from 800 to 

1 000 feet in thickness, composed largely of ash and ' . . tuff, generally light in color. Near the base of this 

formation is the well-known Van Horn or Belshaw 

ranch locality. The Mascall was considered to be of 

middle Miocene age. 

With this digression we lnay now return to the 

Payette formation. In my "Fossil flora of the 

John Day Basin" 2 I discussed certain floras that are 

more or less closely related to those of the John Day 

region, among them that of the Payette formation. 

As this flora is clearly related to that of the Bridge 

1 Lindgren, Waldemar, U.S. Geol. Survey Eighteenth Ann. Rept., pt. 3, p. 632, 

1898. 

2 Knowlton, F. H., U.S. Geol. Survey Bull. 204, p. 110, 1902. 
FLORA OF 1

THE LATAH FORMATION 19 

,Creek locality, which had in the meantime been 

relegated to the upper Eocene instead of the upper 

Miocene, I felt justified in regarding the age of the 

Payette as the same, namely, upper Eocene. This 

reassignment was met with protest by the geologists, 

but on the basis of the material then available this 

was the logical conclusion to be drawn. 

· The matter has been held in abeyance pending 

the discovery of additional data, and these have now 

in a measure been supplied by the investigations 

of Dr. R. W. Chaney, of the Carnegie Institution of 

Washington. In 1921 Chaney visited the Snake 

River valley and procured collections from one or 

two of the original localities as well as from some 

four or five other points, with the result that the 

original flora of 32 species is increased by 17 species, 

bringing the total flora now recognized up to 49 

species. The preliminary results of Chaney's studies 

are set forth in a short paper 3 published in 1922. 

First it may be pointed out that he is now of the 

opinion that a further change in the age assignment 

of the flora from Bridge Creek is probable. He says: 

The writer has not yet brought together all the necessary 

evidence, but recent field studies in the John Day Basin and 

at other points in eastern and central Oregon point to the 

placing of the Upper Clarno formation in the Oligocene rather 

than in the Eocene. If this is correct, and the supporting 

evidence will be brought forth in a subsequent paper, there 

are no atypical Eocene plants in the Payette flora. 

At the time of the original discussion of the Payette 

flora only 10 of the 32 species had a known distribution beyond this formation, but by the work of 

Chaney the number has been increased to 21. His 

analysis discloses that 12 of the 21 species occur in 

the Mascall formation (middle Miocene) and only 

5 ~pecies in the flora from Bridge Creek (upper par,t 

of the Clarno formation). Although mere numerical 

superiority may not be the safest criterion for correlation, it has distinct value. 

. There are, however, other criteria that point to 

the Miocene age of the Payette formation. Thus 

the position of the formation, above basalt lavas, is 

in accord with the relations of the Mascall formation 

to the Columbia River lavas in the John Day Basin. 

Further, vertebrate remains from the Payette found 

by J. P. Buwalda are pronounced by him to be of 

middle or upper Miocene age. It seems, therefore, 

that .. jhe conclusion reached by Chaney must be 

accepted, namely, that the Payette formation is 

proba"oly of Miocene age. He says: 

So far as the plants are concerned, the age would not be 

younger than middle Miocene, and in view of the inclusion 

of Oligocene and possibly Eocene forms, it might better be 

considered as. lower Miocene. The present knowledge of the 

western floras does not justify an attempt to draw the line 

of age too sharply, and at the present time the writer is satisfied 

to make the reference to the Miocene without further specification. 

a Chaney, R. W., Notes on the flora of the Payette formatron: Am. Jour. Sci., 

5th ser., vol. 4, pp. 214-222, 1922. 

EAGLE CREEK FORMATION 

The Eagle Creek formation is a very thick series 

of beds of volcanic ,conglomerate, ash, and tuff, with 

some intrusions of basalt, exposed in the Columbia 

River gorge, mainly in Multnomah County, Oreg., 

and across the river in Skamania County, Wash. 

The flora, described by Chaney/ is a comparatively 

rich one, comprising 72 species, of which 38 are described as new and 14 are not named specifically, 

leaving 20 species with an outside distribution. 

An analysis of the range of these species shows that 

the greater number are found in the flora from Bridge 

Creek, in the John Day Basin, and that a considerable 

number are common also to the Mascall flora. At 

the time Chaney's paper was written the flora · from 

Bridge Creek was considered to be upper Eocene. 

From a comparison of the species having ' an outside distribution, as well as the distribution of species 

obViously closely related to certain of the new forms, 

Chaney concluded that the Eagle Creek flora. seemed 

to show a transition between Eocene and Miocene. 

He says: 

While most closely related to floras of upper Eocene age, 

the E.agle Creek flora is also definitely related to those of 

Miocene age, if these formations have been correlated correctly. 

On the basis of these relations it has seemed proper to consider 

the Eagle Creek flora as transitional between the upper.Eoce:rio 

and Miocene, or, in other words, of Oligocene age. 

In view of what was brought out above regarding 

the flora fro~ Bridge Creek, to which that of theEa.gle 

Creek is obviously related, it is probable that the Eagle 

Creek would now be regarded by Chaney as of Miocene 

age. 

AURIFEROUS GRAVELS IN CALIFORNIA 

In 1878 Lesquereux 5 published a paper o~ the fos~il 

plants of the auriferous gravel deposits of the Sierra 

Nevada, in which he describes over 50 species. From 

their apparent close affinity with liVing · species, their 

more or less close agreement with certain European 

floras, and their association with vertebrate remains, 

they were considered to be of Pliocene age. In later 

years, as additional stratigraphic data and collections 

of plants became available, it came to be accepted that 

the plant-bearing beds, or at least those which supplied 

most of Lesquereux's material, were upper Miocene. 

As more and more intensive stratigraphic work was 

done in the Sierra Nevada it became evident that the 

so-called auriferous gravels represent a phase of sedimentation that was comparatively long, extending from 

upper Eocene time well into and possibly through the 

Miocene. The localities most frequently mentioned 

(such as Table Mountain, Tuolumne Coufity, and 

Chalk Bluffs, Nevada County) fall within the Miocene. 

4 Chaney, R. W., Flora of the Eagle Creek formation: Chicago Univ. Walker 

Mus. Contr., vol 2, No. 5, pp. 1 5-181, pls. 5-22, 1920. 

a Lesquereux, Leo, Harvard Univ. Mus. Comp Zoology Mem, vol. 6, No.2, pp~ . 

i-vi, 1-62, pls. 1-10, 1878. ' 
20 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

MASCALL FORMATION 

The position of the Mascall formation is briefly 

referred to abqve in the section on the Payette formation. The flora of the Mascall formation was described in 1902 in my "Fossil flora of the John Bay 

Basin, Oregon," 6 and embraces about 80 species. As 

already pointed out, the affinity of this flora is with the 

Miocene, and from its stratigraphic position, as well as 

from the vertebrate remains, the positionis fixed with 

much certainty as middle Miocene. 

ELLENSBURG FORMATION 

The Ellensburg formation, which was named by 

G~o. Otis Smith,7 comprises certain fluviatile deposits 

of stratified silt, sand, and .gravel of volcanic materials 

near Ellensburg, Wash., about 150 miles west of the 

Spokane area. The older of these beds are overlain by 

or interbedded with the Wenas basalt. Fossil plants 

have been found in the formation at two localities, one 

about 6 miles squtheast of Ellensburg and the other 

in Kelly Hollow, Wenas Valley, some 15 miles south 

of Ellensburg. The matrix is a white, generally finegrained volcanic ash, identical in appearance with that 

from the Van Horn ranch (Mascall formation), in the 

John Day Basin, Oreg. 

e Knowlton, F. H., U. S. Geol. Survey Bull. 204, p. 106, 1902. · 

7 Smith, G. 0., u:s. Geol. Survey Geol.Atlas, Ellensburg folio (No.86),p.2,1903. 

The Ellensburg flora numbers 15 species, 13 of 

which are found in greater or less abundance in the 

Mascall formation of the John Day Basin, and on this 

basis the Ellensburg formation is considered to be of 

the same age, namely, middle· Miocene. Four or five 

of. the species from the. Spokane area are identical with 

or closely allied to species identified in the Ellensburg 

formation. 

FLORAS OF THE SPOKANE AND COEUR D'ALENE AREAS 

With the above background we may now consider 

the floras of the Spokane and Coeur d'Alene areas. 

The most striking feature of these floras at first glance 

is their very modern appearance, and the apparent 

living analogues are at once suggested for many of the 

forms, ·especially in Ginkgo, Sequoia, Taxodium, Populus, Castanea, Quercus, Ulmu.s, and Acer. It was the 

very modern aspect of the flora of the auriferous gravels 

of California, as well as its resemblance to certain 

European floras, that led Lesquereux originally to 

refer it. to the Pliocene. 

An analysis of the 95 forms that make up the 

Spokane and Coeur d'Alene floras shows that 25 species have a ·distribution' outside .these areas. The 

following table shows the vertical distribution of 

these 25 species: 

Vertical distribution of the extralimital species of the Spokane and Coeur d'Alene floras 

Lance 

formation 

Fort 

Union 

formation 

Kenai 

formation 

Clarno 

formation 

Eocene ~g;~~-6 Oligo- tion cene 

Eagle Mascall A if 

Creek forma- ~user- Miof~~:a- tion gravels cene 

Pliocene 

-----------'----------1------------------------------------

Ginkgo adiantoides_____________________ X X X X X X ------ ------ ------ ------ Sequoia langsdorfii______________________ X X X X ______ ______ ______ ______ X X 

Taxodium dubium______________________ X X X X ______ ______ ______ ______ X X X 

Populus lindgrenL _________________________________________ ~- __ _ ___ __ _ X _ _ _ __ _ _ __ ___ X __________________ , Salix elongata ______________ . ______________________________ ---..,.-- __________ . _________________________ :.. X · Salix perplexa _____________________________________ ..: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X ? _ _ _ _ _ _ X ______ ,... __________ _ Salix dayana ___________________________ ~----- ______ ______ ______ ______ ______ ______ ______ X _________________ _ Betula heteromorpha _____________________________ .__ ______ X ______ ______ ______ X _______________________ _ 

Y Castanea castaneaefolia ________________________ ------ ______ ______ ______ ______ ______ ______ X X ______ ------ Quercus merriamL __________________________________________________________ ,_ _ _ _ _ X X _________________ _ 

Que·rcus cf. Q. pseudo-lyrata_____________ ______ ______ ______ ______ ______ ______ ______ X X ____________ ------ QuercuS payettensis _____________________ ______ ------ ______ ______ ______ X __________________ ---~-- ______ ------ Quercus simulata ______________________________________ · _______ :..._ ______ X X __________________ ------

Ulmus speciosa_________________________ ______ ______ ______ X ______ ______ X? X __________________ ------ Lauros similis__________________________ ______ ______ ______ ______ X? ______ ______ X _______________________ _ .r Laurus princeps________________________ _ _ _ _ _ _ X? _______________ ~ __ __ X __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X ___________ _ Laurus californica ______________________ ------ ------ ______ ______ ______ ______ ______ ______ ______ X X 

" Laurus .grandis _________________________ ------ ------ ______ ______ ______ ______ ______ _____ _ ______ X X 

; Rhus typhinoides __________________ · _____ ------ _________________________ .:.____ ______ X? __ ·____ X ------------ Magnolia day ana:.. _______________________ ..: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ X X 

Acer minor _______________ !.. _________________________________________________ - . _ _ _ _ _ _ _ _ _ _ X _________________ _ 

v !~:~ Liquidambar ~~~~~ pachyphyllum ~ ~ ~ = = = = = = = = = ___________________ = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = ~ = = = = = = = = = = = = = = = = = = = = = = =· = = = = = = ~ ------ --~ -- ------ .:. ______ ______ ______ ______ ______ ______ X X _________________ _ 

Hydrangea be~direL-----------------.,--- ______ ______ ______ ______ ______ ______ ______ ______ X ____________ ------

3 4 3 5 2 3 3 9 13 6 7 1 
FLORA OF THE LATAH FORMATION 21 

The first three species in the above list have so wide the undiffere4iated Miocene, or altogether no less 

a vertical range that they are of comparatively little than 19 species. The Latah formation has 5 species 

value in fixing the age. Another possible element of found in the j upper part of the Clarno formation 

uncertainty may hinge upon the correctness of all (Bridge Creek locality) 3 in the Payette formation, 

the identifications. Conifers are not always easy to and 2 in the Eagle Creek formation, or 9 spec~es in 

identify with certainty unless they ·are exceptionally these three formations. · 

well preserved. As the three species now stand they As already ~ointed out, the Mascall formation of the 

range from Lance to Miocene-indeed, one (Taxodium John Day Basf, Oregon, is now very definitely fixed 

dubium) persists into the Pliocene, and this one con- as middle Miocene in age, and as the latest determinanects with the living species ( Taxodium distichum) tion ·seems to place the upper part of the Clarno, the 

with very little if any change. As a matter of fact it Payette, and the Eagle Creek floras also in the Miocene 

is difficult to draw a satisfactory line between what is the conclusionJ seems justified that the Spokane and 

now called Taxodium dubium-which was long known Coeur d'Alene !floras (Latah formation) are of Miocene 

as Taxodium distichum miocenum-and the living age. T.his floia. is therefore regar __ded as not young. er species. 

A glance at the above table discloses the fact that 

the flora, of the Spokane and Coeur d'Alene areas finds 

its closest agreement with the floras of the Mascall 

formation, · the auriferous gravels, and the Miocene in 

general, 13 of the 25 species being common to the 

Mascall, 6 to the auriferous gravels, and · 7 to 

.than nnddle :N1wcene and not older than lower MwcenTehi. ·· I t f ·t· · till f th h s assigrup.en o posi wn Is s ur er emp a- t 

sized by the distribution of the species t(} which1 cer-

~ain of t~e n1w spec~es are obviously related. This 

IS shown m the followmg table: . I 

Horizons of species related to the Spokane and Coeur d'Alene plants 

I . . Most closely related fossil species Horizon 

Pinus sp ___________ .:. ____________ .:_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Pinus knowltonL ________ -------- Eagle Creek. 

Taxodium, male aments ____________________________________ Taxodium, male aments __________ Mascall. 

Carpinus SP----------------------------------------------- Carpinus grandis ________________ Mascall and Eocene. 

Q b . . {Quercus pseudo-lyrata_---------- }Mascall ~ercus onserl_ - - - - - - - - -- - --- - ----- - - - - - - - - - --- - - - - - - - :- - - Quercus merria;mi- - - - - - - - - - -- - - - . . 

Quercus cf. Q. pseudo-lyrata_ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ Quercus pseudo-lyrata _____ ------ Do. 

Q t .. ' {Quercus payettensis _ _ _ _ _ _ _ _ _ _ _ _ _ Payette. uercus rus 11 - - - - - - --- - - - --- - - - - - - - - - - - - - - - - - - - -- - - - - - - - - - Quercus merriami _______ - - - - - - - - Mas call. 

Quercus spokanensis __________ . __________________ ___ -·- _____ -: Quercus cowlesi ________ ,... _ _ _ _ _ _ _ _ Eagle Creek. 

Quercus chaneyL _______________ '- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Quercus simplex_____ ____________ U ppet part of Clarno. 

Ulmus fernquistL ___ _____ __ ___________ ------..,-- _ __ _ _____ __ _ Ulmus californica ____ ' ..: ______ _ _ __ Auriferous gravels. 

~~~~s ':~~~~~~~~~~s!~= = = = = = = = = = = = = = ==== = = = = = = == = = = == = = = = = = ~~~~su~?rf~~~~;~~ ~== = = =-= = = = = = = = = Mas?afi: Celastrus fernquisti _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Celastrus taurinensis _ _ _ _ _ _ _ _ _ _ _ _ Fort Union. 

Acer chaneyL---------- _-- --- _- _- _- _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Acer angustilobatum__ _ _ _ _ _ _ _ _ _ _ _ Swiss Miocene. 

Of the 13 species in this list 6 are more or less closely 

related to forms in the Mascall formation, 2 each to 

species in the Eagle Creek and auriferous gravels floras, 

and 1 each in the Payette, upper part of Clarno, Fort 

Union, and Swiss Miocene. 

Many of the forms found iri the floras from Spokane 

and Coeur d'Alene are so modern in appearance that 

it may be of interest to note the obvious living affinities 

of the new species. This is brought out in the following table: 

Relation of new species of Spokane and Coeur d'Alene plants to 

species now living 

New fossil species 

Archaeomnium patens ____ _ 

Polytrichites washington-' 

ensis. 

Lycopodium hesperium ____ _ Tumion bonseri_:.. ________ _ 

Libocedrus praedecurrens __ _ 

Typha SP------------:----- Potamogeton sp __________ _ AI:isaema hesperia ________ _ 

Related livin~ species 

Aulacomnium palustre. 

Polytrichum sp. 

Lycopodium carolinianum. 

Tumion californicum. 

Libocedrus decurrens. 

Typha latifolia. 

Potamogeton heterophylla. 

Arisaema triphyllum. 

Relation of new species of Spokane and Coeur d'Alene plants to 

species now livi.ng-Continued 

New fossil species Related living species 

' {Populus alba. Populus hyteromorpha_---- Populus canescens. 

Salix bryani _ _ _ _ _ _ _ _ _ _ _ _ _ _ Salix discolor. 

Alnus, cones ______________ Alnus incana. 

'Betula nanoides_ _ _ _ _ _ _ _ _ _ _ Betula humilis. 

Betula? largei_ ______ ______ Betula papyrif~ra: 

Betula bryanL_ _ _ _ _ _ _ _ _ _ _ _ Betula papyrifera. 

Betula thor _____________ .:._ Betula papyrifera. 

. {Quercus michauxii. Quetcus spokanens1s_------ Quercus prinos. 

Quercus praenigra_ _ _ _ _ _ _ _ _ Quercus nigra. 

Quercus chaneyL __________ J Quercus virginiana. Quercus o btusa_ _ _ _ _ _ _ _ _ _ _ _ Quercus virginiana. 

Quercus, cup __________ ..:.___ Quercus lyrata. 

Ulmus fernquistL _ _ _ _ _ _ _ _ _ Ulmus fulva. 

Magnolia sp _ _ _ _ _ _ _ _ _ _ _ _ _ _ Magnolia f oetida. 

Prunus sp _________ , _______ Prunus americana. 

Cercis? spokanensis__ _ _ _ _ _ _ Cercis canadensis. 

Robinia _______________ ·___ Robinia pseudoacacia. 

Meibomites lucens_ _ _ _ _ _ _ _ _ Meibomia arenicola. 

Diospyros andersonae_ _ _ _ _ _ Diospyros virginiana. 

Diospyros? microcalyx_ _ ___ Diospyros texana. 

Malva? hesperia--~-------- Malva spp. Vaccinium salicoides_ _ _ _ _ _ _ Vaccinium pennsylvanicum. 

Carpites paulownia _ _ _ _ _ _ _ Paulownia tomentosa. 
22 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

COMPARISON OF THE FLORAS FROM THE SPOKANE AND 

COEUR D'ALENE AREAS 

Most of the plants described in this report came from 

the Spokane area, but a single. large and interesting 

collection, submitted by Mr. H. J. Rust, was obtained 

near the bottom of a well 43 feet deep on the south 

slope of Stanley Hill, about 2 miles northeast of Coeur 

d'Alene, Idaho. No detailed stratigraphic study has 

been made of the Coeur d'Alene area, but at my .suggestion Mr. Pardee made a hasty examination in July, 

1923. He states that no exposures of the fossiliferous 

beds were seen, but "remnants of basalt flows that 

appear to overlie the fossil-bearing shale crop out near 

by, and a little farther away granite and schist that 

form the ~edrock are exposed." Mr. Pardee is therefore of the opinion that the relations at Coeur d'Alene 

are in general similar to those atSpokane. 

The Coeur d'Alene flora comprises 25 forms, of which 

13 are regarded as new, 3 are not named specifically, 

and 9 are previously known species. .It is especially 

rich in oaks, as regards both species and individuals, 

probably more than half of the individuals belonging 

to the oaks. Only the following 6 species are common 

to the Spokane area: 

Taxodium dubium. 

Sequoia langsdorfii. 

Betula heteromorpha. 

Quercus merriami. 

Ficus? washingtonensis. 

Prunus rustii. · 

In one way it seems rather strange that there is not 

more in common between the two areas, which are 

separated by only 25 miles, but comparison of the 

lists of plants from the several Spokane collections 

shows that there are few species common to two localities that are separated even by only a few feet vertically or a few miles areally. This localization is doubtless to be ascribed to two sources-the accident of 

fossilization and the extent of exploit~tion. In one 

locality a shower of oak leaves may fall or be blown 

into the water and if not transported to any great 

distance may dominate the deposits. In another locality scattered leaves of many kinds may find a 

resting place in proximity. 

. ECOLOGIC CONDITIONS 

The accompanying illustrations show that many of 

the species1 such as the poplars, oaks, elms, and alders, 

have. a very modern appearance. By using their obvious a:ffimties with living species it is possible to 

deduce certain conclusions regarding the probable ecologic conditions and climate under which these plants 

lived. 

The physical setting that preceded and accompanied 

the entombment of these plant remains has been fully . 

discu~sed by Messrs. Pardee and Bryan in the preceding 

paper and will be only briefly recapitulated here. 

The basement or floor on which the lavas and associated sediments rest is composed mainly of crystalline 

and metamorphic rocks, such as granite, gneiss, and 

schist, and had developed a topography which "was 

apparently even more rough than the mountainous 

lands north and east of the plateau are at present." 

When the lava was extruded it spread in a broad sheet, 

filling the depressions, and as it advanced upon the 

mountainous region it projected into the mountain 

valleys and retired around the intervening spurs "like 

the coast line of a sea." As it pressed up the valleys 

it obstructed the streams, producing ponds and possibly small lakes. The appearance and composition 

of the , fossil-bearing shale are described by Messrs. 

Pardee and Bryan (pp. 4-10). 

In this flora three fairly well differentiated ecologic 

types can be distinguished-hydrophytes, mesophytes, 

and xerophytes. The hydrophytes include what appears to be a leaf of Potamogeton, of a type growing in 

shallow water with leaves both submerged and floating. 

There are also leaves of Typha, which presumably 

lived in very shallow water or in flats continually or 

periodically inundated. At one of the localities, the 

well at Mica, there are numerous fresh-water diatonm. 

A report on these diatoms, with an interpretation of 

the probable conditions under which they lived, is 

given by Dr. Albert Mann on pages 51-55. 

The mesophytes are apparently the most abundant 

element in the flora. The species represented by the 

greatest number of individuals are Populus heteromorpha and Taxodium dubium, of which there are 

literally hundreds of specimens. Their abundance 

and their perfect preservation shows that they must 

have grown very near where they were entombed. 

The Taxodium, if it has been correctly interpreted, 

probably grew in swamps either along streams or on 

the borders of the ponds. The poplars probably grew 

along the streams, together with the several species of 

willows; and the alders, and their leaves fell directly 

into the ponds or lakes, as ,they show little effect of 

transportation. On slightly higher ground back from 

the streams were the magnolias, maples, and chestnuts 

and possib~y some of the oaks, together with the huckleberries, laurels, and elms. · 

The xerophytes or semi-xerophytes probably clothed 

the ridges. These are the several species of oaks that 

have more or less coriaceous leaves. The oak leaves 

are perhaps third in abundance of individuals, and the 

fact that only a few acorns are preserved would seem 

· to indicate that the trees were some distance from the 

streams or ponds, into which the leaves could be 

easily transported by winds. 

It is not always easy to differentiate between mesophytic .. and xerophytic assemblages, for in the living 

floras it usually happens that there is more or less of a 

commingling , of the two elements. As Chaney 8 has 

said: 

s Chaney, R. W., Chicago Univ. Walker Museum ·Contr., vol. 2, No. 5,,p. 246, 

1920. 
FLORA OF THE LATAH FORMATION 23 

In modern forests there is a degree of mixture of ecological 

types, due to the lagging behind of certain relic~ xerophytes 

after the phmt association has become mesophytw, or to the 

advance into a xerophytic association of certain pioneer mesophytes. In the first case mentioned the plants would be dominantly mesophytic with scattered xerophytes; in the second 

case the plants would be dominantly xerophytic with scattered 

mesophytes. 

We may now draw a picture of the probable physical 

settin6 in the Spokane area when these plants were 

entombed. The area was a broad valley flanked by 

rolling hills and ridges, some of which rose 1,500 feet 

or more above the general level, with considerable 

streams coming down from the north or northeast. 

Then came the lava flow, which completely dammed 

the streams, throwing the water back int'O shallow 

lakes or ponds. As the lava was eroded slowly the 

ponding continued for a sufficient length of time for 

a considerable growth of trees, shrubs, and smaller 

herbaceous plants. The open bodies of water were teeming with microscopic diatomaceous life. Here and there 

pond weeds floated on the surface, and about the borders 

were patches of cattails, grasses, and sedges. In the 

swamps adjacent to the open water were the forests 

of bald cypress and an occasional soft maple. Overhanging the streams and in places along· the borders 

of the ponds were the alders and willows and also the 

poplars, of which there were several kinds, some of 

them doubtless forming groves back from the water. 

On the slopes and foothills there were forests of 

deciduous trees, including elms, maples, magnolias, 

laurels, and some oaks. In the moist, rich, shaded 

parts were Indian turnips and doubtless other more 

or less herbaceous growth. Still higher were the 

groves of oaks of several kinds, with a few chestnuts 

and scattered clumps of pine. It is hard to place the 

position of the sequoia and ginkgo, but probably they 

were on the middle slopes. 

· CLIMATE 

The composition of the flora of the Spokane and 

Coeur d'Alene areas indicates that it was distinctly a 

temperate assemblage, if the plants had approximately 

the same climatic requirements as their living allies, as 

there is every reason to suppose they had. It was a 

flora very similar to that now living in the northeastern pa-rt of the United States. 

INSECT REMAINS IN THE LATAH FORMATION 

.. Although the clay shale in which the plants are preserved with such remarkable fidelity is very fine 

grained and in every way fitted for the preservation of 

insect remains, such remains are exceedingly rare-in 

fact, so far as has come to my knowledge, only three 

specimens have been found. These are the elytra of 

a large carabid beetle, apparently of a single species. 

The first one found was submitted to Prof. T. D. A. 

Cockerell, of the University of Colorado, who named 

and described it as Oalosoma fernquisti. 9 It was 

named in honor of the collector. 

SUMMARY 

The flora herein described comes from the vicinity 

of Spokane, Wash., and Coeur d'Alene, Idaho. It 

occurs mainly in clay shale associated with the l~va 

. flows of the Columbia Plateau. These plant-beanng 

beds to which the name Latah formation has been 

give~, have a minimum thickness in the Spokane area 

~ of approximately 1,500 feet. r 

This flora comprises 95 fo~ms, of which 51 ~re 

regarded aShew to science, 18 are not named specifically, and 25 are found in other areas. . 

As a whole this flora is very modern m appearance, 

the ginkgo, cypress, sequoias, oaks, elms, mapl~s, 

poplars, and others being especially similar to certam 

living analogues. 

This. flora has been coin pared with floras f.rom the 

auriferous gravels of California, the Eagle Creek formation of Oregon and Washington, the upper part of 

the Clarno formation (Bridge Creek locality) and the 

M.ascall formation of the John Day Basin, Oregon, the 

Payette formation of Idaho, and the floras at Elko, 

Nev., and Ellensburg, Wash., as well as with more 

distant Eocene and Miocene floras. 

Of the 25 species having an outside distribution, 3 

occur in the Lance formation, 4 (1 doubtful) in the 

Fort Union 3 in the Kenai, 5 in the Clarno, 2 (1 

doubtful) i~ the Eocene, 3 in the Payette, 3 in the Oligocene, 9 in the Eagle Creek, 5 in the Ellens?urg, 13 

in the Mascall, 6 in · the auriferous gravels, 7 1n other 

Miocene beds, and 1 in the Pliocene. Six (1 d~ubtful) of the . 25 species occur in beds of established 

Eocene age, but only one is confined to th~se beds. 

On the other hand, 19 of the 25 species occur in accepted Miocene or higher beds. Thisleaves the upper 

part of the Clarno, the Payette, and the Eagle Creek 

formation, with 9 species in common, which have 

usually been considered as of upper Eocene a?e but 

which are now regarded as probably lower Mwcene. 

The affinity of the floras from the Spokane and 

Coeur d'Alene -areas is undoubtedly with the higher 

beds and the conclusion is reached that they are of 

Mio~ene age. They are not younger than middle 

Miocene nor older than early Miocene. 

THE FLORA 

Phylum BRYOPHYTA 

Class MUSCI 

In the collections made by various. people .in the 

Spokane region the~e are a number of fairly well 

preserved mosses. These were all submitted ~o Mrs. 

E. G. Britton and Dr. Arthur Hollick, of the New 

9 Cockerell, T. D. A., U, S. Nat. Mus. Proc., vol. 64, p. 14, pl. 2, fig. 8, 1924. 

• 
• 

24 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

York Botanical Garden, and Mrs. Britton .has been 

kind enough to prepare the following identifications 

and diagnoses. 

Family MNIACEAE 

Genus ARCHAEOMNIUM E. G. Britton, n. gen. 

With the characters of the species. 

Archaeomnium patens E. G. Britton, n. sp. 

Plate VIII, Figures 1, 2 

Plants up to 2 centimeters· high by 3 millimeters broad; 

stems simple or branched, erect, apparently mentose, with 

one branch bearing a curved, leafless apical prolongation about 

1 centimeter in length; leaves crowded and spreading, larger 

and more numerous at the apex of the stems, lanceolate-acuminate, about 1.5 millimeters long by 0.5 millimeter broad, seemingly entire and costate to apex, with revolute margin. · 

Resembles the living species A ulacomnium palustre (Linne) 

Schwaeger in the leafless prolongation of the stem with a slight 

induration of a capitate tip, the presence of tomentum, and· the 

larger crowded apical leaves. 

Occurrence: Latah formation, cut No. 1 on Spokane, Portland & Seattle Railway, Spokane, Wash., 

collected by Henry Fair and C. E. Fernquist, June, 

1922. . 

Family POLYTRICHACEAE 

Genus POLYTRICmTES E. G. Britton, n. gen. 

With the characters of the species. 

Polytrichites spokanensis E. G. Britton, n. · sp. 

Plate VIII, Figures 3, 4 

Plant erect or slightly decumbent at base; stems up to 2 

centimeters high, branching; leaves not crowded except at the 

summit of the stems, composed of two distinct portions-a 

paler basal part, which is erect, appressed, and clasping the 

stem, and an apical part, which is bent outward and spreading, 

which measures 3 to. 4 millimeters in length, is evidently strongly 

veined and keeled, apparently entire and sljw.rply subulate. 

Although much resembling, when magnified, certain living 

species of Polytrichum, the actual size of the plant precludes 

any definite reference to this genus. 

Occurrence: Latah formation, Deep Creek, northwest of Spokane, Wash., collected by Henry Fair and 

C. E. Fernquist, June, 1922. 

Moss, genus and species? 

Plate VIII, Figures 5, 6 

N otwithstandi~g the extensive coflecting that has 

been done in the Spokane area mosses appear to be 

but poorly represented though evidently diversified, 

for of the three specimens thus far found two are 

described above as new genera; the third specimen is 

here figured. It consists of several densely leafy 

stems that it seems to me might without violence be 

referred to Polytrichites, described above, but it has 

passed under the critical eye of Mrs. Britton, arid she 

considers it too obscurely preserved to permit adequate 

diagnosis, and it must therefore remain without a 

name. It is presented simply to show that this type 

of vegetation is present. 

Occurrence: Latah formation, Deep Creek, northwest of Spokane, Wash., collected by Henry Fair and 

C. E . Fernquist, April, 1922. 

Phylum PTERIDOPHYTA 

Fern, fragment \ 

Plate IX, Figure 10 

Among several hundreds of specimens that have 

been studied from the Spokane area this is the only 

fern observed, and it, of course, has no value beyond 

indicating the presence of this plant type. It is the 

basal portion of a pinna or pinnule that was evidently 

coriaceous and has a very strong mid vein and numerous 

strong veins that arise at an angle · of about 45°. 

The veins fork just as they emerge from the midvein 

and twice or three times before reaching the margin. 

None of the margin is retained except the base, and 

this is entire. 

Occurrence: Latah formation, cut No. 2 on OregonWashington Railroad & Navigation Co.'s line, Spokane, 

Wash., collected by Henry Fair and Kirk Bryan, 

May, 1923. 

Class EQUISETALES 

Family EQUISETACEAE 

Equisetum, underground stem 

Plate IX, Figure 1; Plate XXVI, Figure 5; Plate XXIX, Figure 8 

Equisetum was apparently a rare element in this 

flora, as only three specimens have been found thus far. 

The best preserved is a segment of an underground 

stem with three groups of opposite, sessile, . large 

tubercles. The stem has four or five strong, somewhat 

irregular longitudinal ridges: The tubercles are unusually large, spherical or nearly so, marked with 

strong ridges. · 

Occurrence: Latah formation, cut on Spokane, Port..: 

land & Seattle Railway in Spokane, Wash., collected 

by Henry Fair and C. E. Fernquist, June, 1922. 

Order LYCOPODIALES 

Family LYCOPODIACEAE 

Lycopodium hesperium Knowlton, n. sp. 

Plate VIII, Figure 7 

Sterile stems unknown; fertile spike erect, very 

slender, over 3.5 centimeters long, about 3 millimeters 

in diameter; bracts apparently cordate, short acuminate at apex, the margins entire, with the oval -sporangia in their axils. 

The fragmentary specimen, the only one found in 

the collections, lacks both base and apex and was 

probably at least 4 centimeters long. It is unfortunate that a leaf-bearing portion of the stem is not 

preserved. Among living ;:;pecies it appears to ap-
, FLORA OF THE LATAH FORMATION 25 

proach most closely Lycopodium carolinianum Linne, 

of the moist pine barrens from New Jersey to Florida 

and Louisiana, especially near the coast. This species 

has the bracts cordate, short. acuminate, and mostly . 

entire, thus agreeing with the fossil so far as the latter 

can be made out. 

Only five species of Lycopodium have been reported 

in a fossil state in this country. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. 

Rust, July, 1920. 

Phylum SPE~MATOPHYTA 

Class GYMNOSPERMAE 

Order GINKGOALES 

Family GINKGOACEAE 

Ginkgo adiantoides (Unge.r) Heer 

Plate VIII, Figures 10, 11 

Ginkgo adiantoides (Unger) Heer, Flora fossilis arctica, vol. 5, 

Abt. 3, p. 21, pl. 2, figs. 7-10, 1870. 

·ward, U.S. Geol. Survey Sixth Ann. Rept., p. 549, pl. 31, 

1igs. 5, 6, 1886; idem; Bull. 37, p. 15, pl. 1, figs. 5, 6, 1887. 

Chaney, Chicago Univ. Walker Mus. Contr., vol. 2, No. 

5, p. 159, pl. 5, fig. 1, 1920. 

Thus far only three leaves of Ginkgo have been found 

in the Spokane area. One was collected in 1910 and 

the others in April and June, 1923, and as collecting 

in the area has been intensive between these dates it 

is safe to assume that Ginkgo was not a very conspicuous element of this flora. 

In all the specimens the leaf substance is so well preserved that the leaf can be removed from the matrix 

intact and mounted between small plates of glass. 

This condition is unusual_:.:_in fact, these are the only 

leaves of Ginkgo that I have seen that could be completely removed from the matrix. There are, however, 

a few coniferous leaves in the Spokane material that 

are equally well preserved. (See Tumion, pp. 25-26 .. ) 

Their thick, leathery texture and resinous 11ature are 

doubtless the reason for their excellent preservation . 

. Ginkgo is a very ancient type that has come down 

to the present with very little change, at least in the 

leaves. There is a considerable range in the degree of 

lobation in the leaves of Ginkgo biloba, the only living 

species, some being practically entire and others so 

deeply lobed as to be almost bisected. Ginkgo was a 

very abundant element in the Jurassic flora, and a 

good many nominal "species" have been differentiated, yet it is seemingly possible to duplicate many 

of these forms among the various forms of the living 

species, and differentiation is increasingly difficult as 

we ascend in the geologic time scale. Although the 

leaves from Spokane appear to be identical with what 

has been called Ginkgo adiantoides (Unger) Heer, they 

are practically identical with certain forms of the 

living species. The margin is undulate with but slight 

indentation of the central sinus, and in this particular 

the form agrees with specimens so identified by 

Chaney 10 from the Eagle Creek formation, where it is 

abundant. 

Occurrence: Latah formation, in S., P. & S. cut 

No. 1, Spokane, Wash., collected by T. A. Bonser, 

specimen now in the U. S. Nat. Mus., No. 37192; 

inS., P. & S. cut No.3, Spokane, collected by Leland 

Hirst, April, 1923 (Pl. VIII, fig. 10); in the gully at 

Fivemile Prairie, east of Spokane, collected by Miss 

Arleen Schmidt, June, 1923 (Pl. VIII, fig. 11). The 

last two specimens preserved in the Spokane Public 

Museum. 

Order CONIFERALES . Family TAXACEAE 

Subfamily TAXEAE 

Tumion bonseri Knowlton, n. sp. 

Plate X, Figure 3 

This species is based on the /fragment of branchlet 

figured. It is a segment about 5 centimeters long, 

broken from what was evidently a long, stout branchlet which is nearly 3 millimeters in diameter. The 

leaves are scattered at remote and somewhat unequal 

distances and jtre inserted spirally but become tworanked by a twist of the petiole. They are 2.5 to 3 

centimeters long and about 3 millimeters wide. They 

are broadest at the base, wh~nye they are abruptly 

n·arrowed below and gradually above to what appears 

to be a short callous point. The leaf substance is so 

well preserved that a whole leaf may be separated 

from the matrix, and when it is mounted in glycerine 

or Canada balsam the details of its cell structure can 

be stu.died under a compound microscope almost as 

well as those in a living leaf. The under side of the 

leaf shows a rather strong midrib, and on either side 

of it a broad band on which the stomata are borne. 

Altogether there are ·about 25 longitudinal rows of 

stomata, each with two large guard cells. The bands 

containing the stomata are darker in color than the 

remainder of the leaf, but whether the rows of stomata 

are in grooves could not be made out with certainty. 

T.he cells outside the bands of stomata are rectangular 

and mainly about twice as long as they are broad. 

The genus Tumion of Rafinesque ( Torreya of Arnott) 

comprises four species, two of which are American and 

two are natives of Japan and China. Of the American 

species, Tumion taxijolium Greene is found only in a 

very small area along Apalachicola River in Florida 

and Tumion calijornicum Greene is pretty well distributed ove~ the State of California, being most 

abundant and of the largest size in the northern Coast 

Ranges. The California species is a tree from 50 to 

70 or occasionally 100 feet in height and from 1 to 2 

or exceptionally 4 feet in diameter. 

10 Chaney, R. W., Chicago Univ. Walker Mus. Oontr., vol. 2, No.5, p. 159, pl. 5, 

fig. 1, 1920. 
26 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

The fossil species from Spokane appears to be nearest 

to Tumion californicum, from which it differs in its 

much smaller leaves, with broader stomatiferous 

bands. Otherwise the general appearance is much the 

same in both. 

Six nominal fossil species of Tumion ·from North 

America have been described, all from Cretaceous 

rocks. The two species ( Torreya falcatum and T. virginicum) fr~m the Patuxent formation of Virginia described by Fontaine 11 are very doubtfully allocated to 

Tumion-in fact, they are quite different from the 

living species. Tumion oblanceolatum Lesquereux,12 

from the Dakota of Colorado, with the leaves attached 

by their whole base and thence decurrent down the 

branchlet, is also doubtfully referred to this genus, and 

the two species described by Dawson 13 (Tumion demifolium and T. dicksonioides), from the Upper Cretaceous of Alberta, are even more remote from the 

living Tumion. Dawson's species are said by Lesquereux to resemble certain of Heer 's species from the 

Cretaceous of Gr enland, but even so it is evident that 

all are greatly in need of revision. 

The form from the Spokane area here described is 

clearly more closely related to the living forms than 

any previously described from this country-in fact, it 

hardly differs except in size from the · living Tum~on . 

californicum. 

This species is named in honqr of Prof. T. A. Bonser, 

curator of the Public Museum of Spokane, who nat 

only submitted the type specimen but has been especially generous in supplying material and informa-

. tion for this study. 

Occurrence: Latah formation, Spokane, Wash., collected by T. A. Bonser. 

Subfamily ABIETINEAE 

Pinus sp. 

Plate VIII, Figure 9 

Leaves in clusters of three, the sheath deciduous; 

leaves more than 4.5 centimeters in length, about 1 

millimeter wide, each with a faintly indicated median 

nerve or midrib. 

I have hesitated to give this form a new specific 

name, as it is the only specimen of a pine that is present 

in the collections, and proper characterization of a 

species on such meager data is difficult. So far as can 

be made out the sheath at the base of the cluster of 

leaves is absent, and hence it is believed to belong to 

the group of so-called white or soft pines. Most of 

the American species belonging to this s~ction of the 

genus have the leaves in clusters of five, but there is a 

small group of species in which the leaves are in one to 

11 Fontaine, W. M., U. S. Geol. Survey Mon.15, pp. 234, 235, pl. 109, fig. 8; pl. 

113, fig. 4, 1889. 

12 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous and Tertiary floras), p. 30, pl. 1, fig. 2, 1883. 

13 Dawson, J. W., Roy. Soc. Canada Trans., vol. 1, pp. 21, 25, pl. 2; fig. 4; pl. 5, 

figs. 20, 20a, 1882. 

four leaved clusters, and there is also a single North 

American species (Pinus chihuahuana Engelmann) belonging to the pitch or hard pines, which has the sheath 

deciduous and the leaves in threes. · 

This cluster of leaves from the Spokane area is 

similar to Pinus knowltoni Chaney, 14 from the Eagle 

Creek formation of Multnomah County, Oreg., and 

may indeed be identical with it. The description 

given by Chaney agrees very well with ·the specimen 

in hand, though he says nothing about the sheath. 

The figure of Pinus knowltoni showing the leaves is so 

obscure that nothing can be ;made out of it, and it is 

impossible to compare it with the Spokane specimen. 

Nothing like the staminate cones has been noted in 

the Spokane material. -

Occurrenc~: Latah formation, well near Mica, 

southeast of Spokane, Wash., collected by Thomas 

Large for J. T. Pardee, August, 1922. 

Subfamily TAXODIEAE 

Sequoia· Iangsdorfii (Brongniart) Heer 

Pia te IX, Figures 3-6 

Sequoia Zan sdorfii Brongniart) Heer, Flora tertiaria Helvetiae, 

vol. 1, p. 54, pl. 20, fig. 2; pl. 21, fig. 4, 1855. 

Lesquereux, U. S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous and Tertiary floras), p .. 240, pl. 50, figs. 2-4, 

1883. 

Knowlton, U. S. Geol. Survey Bull. 204, p. 25, 1902. 

S equoia langsdor.fii has almost as wide a distribution, 

both vertical and areal, as Taxodium dubium ( T. 

distichum miocenum), and as with · that species it 

seems more than possible that several fo;rms of this 

type have been confused, as otherwise considerable 

variation must be aecounted for. 

This form is fairly abundant in the Spokane area 

and, as may be seen from the figures, agrees with 

the usual figures . of this species. One specimen 

(fig. 5) has the ;male aments at the tip of the branchlet 

and hardly emergent from the apical leaves. This 

proves conclusively that it is a Sequoia and not a 

Taxodium, with which it is associated. 

The branchlet shown in Figure 4 is quite similar to 

the lower portion of the branchlet figured by Lesquereux 15 from the auriferous gravels of California 

under the name Sequoia arigustifolia and should 

perhaps be identified with that form, though it seems 

improbable that two species so closely allied as these 

seem to be should occur in the same beds. The other 

specimens here figured are certainly not . to be distinguished from Lesquereux's ,figures of Sequoia 

langsdorfii from the John Day Basin.16 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d-'Alene, Idaho, collected by H. J. Rust, 

( 

14 Chaney, R. W., Chicago Univ. Walker Mus. Contr., vol. 2, No.5, p.160, pl. 5, 

figs. 3, 4, 1920. 

15 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 8 (Cretflceous and Ter· 

tiary floras), p. 252, pl. 58, fig. 3, 1883. 

16 Idem, pl. 50, figs. 2, 3. 
FLORA OF THE LATAH FORMATION ' 27 

July, 1920; west bank of Deep Creek half a mile above 

mouth, northwest of Spokane, Wash., cut 1 mile west 

of Shelly Lake, about 10 miles east of Spokane, and 

well at Mica, 10 miles southeast of Spokane, collected 

by Henry Fair and C. E. Fetnquist, 1922. 

Sequoia? sp. 

The material from the Spokane area submitted by 

T. A. Bonser and Thomas Large includes two lots of 

fossil wood. One is a solid block about 7 centimeters 

long and nearly 6 centimeters in diameter and was cut 

from a log about 15 feet long and 2 or 3 feet in diameter 

found at Division Street and the Spokane International Railway, in the city of Spokane. It was found 

in a pocket of clay, sand, and gravel between two 

lava flows. The other material consists of several 

fragments brought up from shale interbedded with 

lava 400 feet below the surface in a deep well at the 

State Custodial School near Medical Lake, sputhwest 

of Spokane. 

The specimen from the large log is dark brown, 

. almost black, and heavy and has apparently undergone 

considerable mineralization; the other specimens are 

light brown and show little or no evidence of infiltrating minerals. 

No thin sections of these specimens have been cut, 

and the identification must be considered tentative, 

though so far as can be judged from examination with 

a low-powered microscope the structure is that of 

Sequoia. 

Occurrence: Latah formation, between lava flows 

at Division Street and the Spokane International Railway, Spokane, Wash., from a log 15 feet long and 2 to 3 

feet in diameter, collected in 1909 and submitted by 

T. A. Bonser; small fragments from depth of 400 feet 

in well at State Custodial School, Medical Lake, 20 

miles southwest of Spokane, collected by Thomas 

Large, 1922 

Taxodium dubium (Sternberg) Heer 

Plate IX, Figures 2, 7-9; Plate X, Figure 2 

Taxodium dubium (Sternberg) Heer, Flora tertiaria Helvetiae, 

vol. 1, p. 49, pl. 17, figs. 3, 15, 1855. 

Berry, U, S. Geol. Survey Prof. Paper 91, p. 171, pl. 15, 

figs. 4-16, 1916. 

Taxodium distichum miocenum Heer, Miocene baltische Flora, 

p. 18, pl. 2, pl. 3, figs. 6, 7, 1869. 

Newberry, U. S. Geol. Survey Mon. 35, p. 22, pl. 47, fig. 6; 

pl. 51, fig. 3; pl. 52, figs. 2, 3; pl. 55, fig. 5, 1898. 

Knowlton, U. S. Geol. Survey Bull. 204, p. 27, 1902; 

Alaska, vol. 4, p. 152, Harriman Alaska Expedition, 1904; 

Washington A cad. Sci. Pro c., vol. 11, pp. 204, 207, 1909. 

Penhallow, North American gymnosperms, p. 217, D07; 

Report on Tertiary plants of British Columbia, p. 91, 

1908. 

The plant here designated Taxodium dubium is by 

far the most abundant species in the collections, occurring literally in hundreds. They are practically all 

detached branchlets with only a few detached leaves. 

There is a considerable range in the length and shape 

of the leaves, but they agree in a number of essential 

particulars. Most of the branchlets are slender, 

with a number of thin longitudinal lines or ridges. 

The leaves are attached at points all around the branch 

but by torsion at the base they are disposed in a tworanked flat spray. The leaves are rather narrow, 1.5. 

to 2.5 centimeters long., qbtusely pointed at the apex, 

and contracted at the base to a very short petiole or 

almost sessile. The leaves are not decurrent, though 

there is a line running down the branchlets for a short 

distance. They have a very distinct midrib. 

The propriety of referring these branchlets to 

Taxodium dubium may be discussed. Under the name 

Taxodium distichum miocenum or occasionally as 

Taxodium dubium, branchlets of this type have been 

identified from a great number of localities throughout 

the Northern Hemisphere ranging in age from lower 

Eocene to Pleistocene and thence through many 

Pleistocene deposits to the living bald cypress of the 

coastal swamps of the Eastern and Gulf States. To 

judge by the figures given by the several authors 

there is a considerable variation in size and appearance, and it may be that more than one species has 

been confused, but as it is impossible without an 

adequate .series of specimens to determine the specific 

limits, the species may be. taken ·as a type of tree that 

had this wonderful geologic and geographic distribution. The specimens from the 'Spokane area agree 

well with many of the figures from both European 

and American localities, and there is no doubt that 

they can properly be classed with Taxodium dubium. 

They are also very much like some of the smaller 

examples of Taxodium tinajorum Heer/7 from the 

Kenai formation of Alaska and the Miocene of Spitzbergen. 

In 1872 Lesquereux 18 described some coniferous 

branchlets from Elko, Nev., under the name Sequoia 

angustifolia. This species was figured in 1878 in his 

"Tertiary flora" 19 and characterized as follows: 

Branches short, slender; leaves at unequal distances, some· 

times very close, two or three together, or very distant, often 

dimorphous, · linear-lhnceolate, taper-pointed, open or curved 

backward, decurrent; middle nerve indistinct. 

To this description he added the following comment~ 

This form, though very variable, preserves its peculiar 

characters: the narrow, lanceolate, acute leaves, decurrent but 

not narrowed at base, with thin scarcely distinguishable middle 

nerve. 

Unfortunately only one of the figured types of 

Sequoia angustifolia ("Tertiary flora," .pl. 7, fig. 6) is 

preserved in the United States National Museum, and 

as this happens to be the smallest and least perfectly I 

17 Heer, Oswald, Flora fossilis alaskana, p. 22, pl. 1, figs. 1-5, 1869. 

18 Lesquereux, Leo, U.S. Geol. and Geog. Survey Terr. Ann. Rept. for 1872, p. 

372, 1873. . 

19 Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary flora): p. 77, 

pl. 7, figs. 6--10, 1878. 
28 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

preserved one, Lesquereux's diagnosis can not be 

confirmed. 

A fe~ y~ars later Lesquereux 20 identified his Sequoia 

angust~foha from the auriferous gravels at Corral 

Hallow, Calif., and gave a single·figure, and in 1902 

I admitted a specimen from the Mascall formation 

".in ~y "~lora of the John Day Basin," 21 largely on th~ 

basis of Its resemblance to the specimen from California. · 

~ I have a large number of specimens of coniferous 

branchlets recently .collected at Elko, Nev., and they 

do not agree at all with Lesquereux's diagnosis and 

figures of his S equouia angustijolia. One of the Elko 

specimens has been figured for comparison (Pl. IX, 

fig. 7), and from this it will be noted that the leaves 

are irregular and open or spreading, are obtuse at the 

apex instead of acuminate, and are distinctly con- · 

tracted at the base and have a very distinct midrib. 

This form is distinctly a Taxodium and not a Sequoia. 

If the diagnosis and type figures of Sequoia angustifolia ar,e correct, it obviously can not be the form that 

is now so well known from Elko. 

Although the specimens of Taxodium dubim are so 

~bundant in ~he present collection,s, only one example 

In the flowering state has been noted. This is shown 

on Plate IX, Figure 5, and is clearly the staminate 

inflorescence of a Taxodium and in all probability 

belongs with this species, but as there is no absolute 

connection between them, it has been figured without 

specific designation. . · 

Occurrence: Latah formation, Edwards ranch, 

Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. 

Rust, July, 1920 (Pl. IX, fig. 8); Deep Creek half a mile 

above mouth, northwest of Spokane, Wash. (Pl. IX, 

fig. 2), and cut 1 ~le west of Shelly Lake, 10 miles 

east of Spokane, collected by Henry Fair and C. E. 

Fernquist, 1922; cut along Spokane, Portland & 

Seattle Railway, Spokane (Pl. IX, fig. 9; Pl. X, fig. 2), 

collected by T. A. Bonser. 

Taxodium, male aments 

Plate X, Figure 4 

Among the several hundred coniferous branchlets 

the one here figured is the only one showing organs 

of reproduction. These are undov.btedly the staminate flowers of a Taxodium and probably belonged 

to the species here designated Taxodium dubium. 

They agree perfectly with those from the Mascall 

formation figured under the same caption in my 

"Flora of the John Day Basin." 22 

, Occurrence: Latah formation, Deep .Creek half a 

mile above mouth, Spokane, Wash., collected by 

Henry Fair and C. E. Fernquist, 1922. 

20 Lesquereux, Leo, U.S. Geol. Survey Terr, Rept., vol. 8 (Cretaceous and Tertiary floras), p. 240, pl. 50, flg. 5, 1883. 

21 Knowlton, F. H., U.S. Geol. Survey Bull. 204, p. 24, 1902. 

22 Idem, p. 27, pl. 1, figs. 4 6. 

Subfamily CUPRESSINEAE 

Libocedrus praedecurrens Knowlton, n. sp .. 

Plate VIII, Figure 8 

Similar to the living Libocedrus · decurrens 'rorrey 

but more robust, the branches and branchlets nearly 

twice as thick as in the ordinary living specimens. 

The little fragment figured is all that has been found 

of this form. It is small to serve as the basis of a supposed new species, and this assignment must be considered tentative and must await more complete material before it can be positively settled. 

The incense cedar (Libocedrus decurrens Torrey) is· 

found in the mountains of southern Oregon, the Sierra 

Nevada and Coast Ranges of California, the western 

edge of Nevada, and northern Lower California. It 

is a tree from 75 to 100 feet high and is 2V2 to 4 feet 

(exceptionally 5 or 6 feet) in diameter. According to 

Sudworth it attains an age of some 500 to 700 years. 

It does not now live within some hundreds of miles 

of the Spokane area, but if the fragment here figured 

is . correctly identified, the immediate forerunner of 

the species existed in Miocene time far to the north 

of its present habitat. 

Occurrence: Latah formation,· cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected for and submitted by the Spokane Public 

Museum. 

Class ANGIOSPERMAE 

Subclass MONOCOTYLEDONES · 

Order PANDANALES 

Family TYPHACEAE 

Typha? sp. 

Plate IX, Figure 11 

The collection made by R. W. Chaney in the 

Spokane area includes a single fragment of a monocotyledonoJ].s leaf . . It was evidently a long, narrow, 

cattail-like leaf about 1 centimet.er wide and has 

parallel veins of three degrees. The major nerves are 

strong and are about 1.5 millimeter apart. Between 

these are three less strong veins, and between these 

one to three very fine veins. The cross veins are 

usually between the veins of the second degree, 

though here and there a cross vein may pass over 

two of . the second-rate parallel veins. 

This fragment is so small that it is possible only to 

characterize · it in a general way. It appears to be a 

leaf of Typha, but as this is not certain the reference 

to Typha has been questioned. It simply serves to 

direct attention to the fact that a plant of this type 

was present. 

Occurrence: Latah formation, Spokane, Wash., 

collected by R. W. Chaney, July, 1921, specimen in 

the University of California, No·. ~· 
FLORA OF THE LATAH FORMATION 29 

Order NAIADALES 

Family POTAMOGETONACEAE 

Potamogeton sp. 

Plate X, Figures 5, 6 

This appears to be a fragment of the basal portion 

of a thin, pellucid, grasslike submerged leaf of Potamogeton. It is narrowly linear, narrowed below to a 

long wedge-shaped point of attachment, and of unknown shape above. There is a fairly strong midvein, 

and on each side of it there are three or four very 

thin, somewhat irregular veins, connected by more 

or less irregular cross veins. 

As nearly as I may judge from so small a fragment 

it appears to resemble most closely the submerged 

leaves of the living Potamogeton heterophyllus Schr·eber. 

This is a highly variable species, occurring in different 

forms throughout almost all of North America except 

the extreme north and also in Europe. Its submerged 

leaves are linear-lanceolate, from 1 tb 6 or 7 inches 

long and 1 to 8 lines wide. 

As this flora was deposited in ponds or slow-moving 

streams it is reasonable to suppose that the habitat 

would be congenial for Potamogeton-in fact, it is 

surprising that there is not more evidence of the 

presence of this genus. 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Order GRAMINALES 

Grass, leaf 

Plate X, Figure 7 

The small specimen here figured is of little value 

except to indicate the undoubted presence of this 

group of plants. It is a fragment of the apical portion 

of a leaf about 5 centimeters long and 2.5 millimeters 

Wide. It is deeply channeled in the middle. 

Specimens that are little if any better preserved 

than this have received both generic and specific 

names, but there is hardly one chance in a thousand 

that such a form could be correctly allocated or 

identified subsequently. 

Occurrence: Latah formation, cut on . Chicago, 

Milwaukee & St. Paul Railway near Spokane, Wash., 

collected by Kirk Bryan, June, 1923. 

Grass?, genus? 

Plate X, Figures 8, 9 

This small and rather obscurely preserved specimen 

appears to be a small, creeping grass. The basal 

part apparently consists of a radicle from which two 

or three rhizomes arise. These rhizomes were apparently procumbent or creeping, with short, erect, 

compact, leafy or scaly branches. 

85658°-26--3 

Dr. Arthur Hollick has been kind enough to compare this specimen with living rna terial in the herbari urn 

of the New York Botanical Garden, especially in those 

genera of grasses with creeping· stems, such as Eragrostis, Syntherisma, Dactyloctenium, Elusine, and 

Oapriola, and although there is a general resemblance 

it is not sufficiently close to warrant even a generic 

identification. This specimen seems most like a 

grass and has been figured in the hope that someone 

may be able to place it. 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, W~sh., collecte'd by Henry Fair apd C. E. Fernquist, April, 1922. 

Order ARALES 

Family ARACEAE 

Arisaema hesperia Knowlton, n. sp. 

Plate X, Figure 1 

The material from the Spokane area . includes the 

single specimen of this plant that is here figured. 

It is a globose head of fruits or " berries " borne on a 

long, naked peduncle. The head is about 2 centimeters 

in diameter and bears a number (nine are shown in the 

side view of the specimen) of globose fruits or berries 

that are about 4 millimeters in diameter. The surface of these berries is more or less corrugated or 

irregularly wrinkled,· as if they had been fleshy or had 

had a fleshy covering with perhaps a hard "stone" 

beneath. Of the supporting organ or peduncle 3.5 

centimeters is preserved, but it was longer than this, 

as it runs off the matrix without evidence of attachment. It is slightly more than 2 millimeters broad 

and is striate or wrinkled longitudinally, a feature 

which indicates that it was fleshy. " 

So far as I am able to determine this specimen is 

closely similar to the fruit of the living Arisaema 

triphyllum (Linne) Torrey, the Indian turnip of the 

eastern United States, which ranges from Nova 

Scotia to Florida and west · to Ontario, Minnesota, 

Kansas, and Louisiana, delighting especially in moist 

woods and thickets. The fossil form has a longer, 

more uniform-sized peduncle than the living species. 

the head is globose rather than ovoid, and the berries 

are apparently wrinkled instead of being smooth and 

shining. Whether these differences are sufficient to 

warrant a generic separation seems doubtful, and if 

the form is correctly interpreted, as it seems to be, 

the presence of the genus in this flora is placed on a 

secure footing. 

Two other fossil species from this country have 

be~n described under the name Arisaema-namely, 

Arisaema cretacea · Lesquereux, from the Dakota 

sandstone of Kansas and the Magothy formation of 

Cliffwood, N.J., and Arisaema? mattawanense Hollick, 

also from the Magothy formation at Cliffwood, N.J. 
30 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

However, both these are based on portions thought to 

represent the spathe and can not be compared with the 

present specimen, quite aside from the marked difference in age. The genus has not been reported in a 

fossil state outside of the United States. No other 

portion that can be referred to Arisaema has been 

found in the Spokane area. 

Occurrence: Latah formation, Deep Creek, northwest of Spokane, Wash., collected by Henry Fair and 

C. E. Fernquist, 1922. 

Subclass DICTOTYLEDONES 

Order SALICALES 

Family SALICACEAE 

Populus heteromorpha Knowlton, n. sp. 

Plate XII, Figures 8-10; Plate XIII, Figures 1-7; Plate XIV, 

Figures 1-3; Plate XV, Figures 3-5 

This form is represented by approximately 200 

specimens, and it is without exception one of the most 

polymorphous species that I have ever studied. 

If it were not for connecting forms it would be easy 

to select a number that are seemingly so distinct as to 

merit specific separation, but when the specimens are 

viewed as a whole it seems impossible to draw any 

definite lines. From the carbonaceous substance 

that is still present in many specimens it is evident 

that the leaves were rather thick and coriaceous. 

They had a fairly stout petiole about 2.5 centimeters in 

length. In perhaps a majority of the specimens the 

leaves are ovate or ovate-elliptical, with a rounded or 

very obtusely wedge-shaped or nearly truncate base. 

They are all more or less obtuse, and some of them are 

rounded at the apex. From the ovate form there 

is variation in two directions. In one, shown in Plate 

XII, Figure 10, the apical portion is proportionally 

more elongated, a form reached through the forms 

shown in Plate XIII, Figure 6, and Plate XIV, 

Figure 2. In the other type the apical portion is 

short and obtuse, and the basal portion is expanded 

until the outline is almost circular or even reniform, 

as. shown in Plate XIII, Figures 2 and 5, and Plate 

XV, Figure 3. 

In the configuration of the margin there is considerable variation. In the smallest leaf noted 

which ' is only 2 centimeters long and 1.75 centimeters 

broad, shown in Plate XII, Figure 9, the margin is 

slightly undulate. In the leaf shown in Plate XII, 

Figure 8, it is entire except for two slight basal lobes. 

A few of the large leaves have a similar marginal 

outline, as shown in Plate XV, Figure 5; or, as shown 

in Plate XIII, Figure 2, there may be two small 

lobes on each side. In some of the broader forms 

the effect is to become three-lobed with perhaps 

undulations or slight minor lobes. 

The principal nervation in these leaves is essentially 

the same-three-ribbed from the top of the petiole. 

The midrib is slightly larger than the ribs and ha8 

usually three or four pairs of secondaries in the -

upper portion, these curving upward and arching 

near the border. The lateral ribs are usually much 

curved and pass upward for varying distances, some 

of tnem nearly or quite reaching the apex, others 

joining the lowest pair of secondaries on the midrib. 

In the very broad leaves these ribs may reach up 

for only half the length of the blade. They have 

several branches on the outside which arch near 

the margin, some of them with two or three series 

of loops. The nervilles are numerous, thin, and 

nearly always broken. The finer nervation forms 

irregularly quandrangular areas. ~ 

This species does not appear ·to be very closely 

similar to any living North American form, but it 

is suggestive of Populus alba Linne and Populus 

canescens Smith, of western and southern Europe. 

In diversity of form it is especially like Populus 

alba, which has leaves ranging from ovate or elliptical 

to markedly three-lobed ~ith variously toothed 

margins. The primary nervation in P. alba shows 

three ribs from the top of the petiole, but the lateral 

ribs do not ascend so high as they do in many of 

the leaves of Populus heteromorpha. 

Certain fossil American species, however, show 

strong points of agreement with the leaves of P. 

heteromorpha. These are leaves of the type of 

Populus arctica Heer, which are so abundant in the 

Arctic Eocene and especially in the Fort Union formation. In these the lateral ribs arch around and 

terminate in or near the apex of the blade. This 

feature, as already pointed out, is to be noted in 

the leaves under consideration, but it IS not so marked 

as in Populus arctica and its more or less close relatives. 

It seems possible that the leaves of P. heteromorpha 

are showing a transition from the three-ribbed arctica 

type to the pinnate-veined leaves of most modern 

forms. It is held by some students that the forms 

of the arctica type are not properly referred to Populusthat they represent, for instance, archaic survivals 

from the Trochodendraceae-but if the above interpretation is correct there may be an actual transition between the palmately r~bbed Eocene types 

and the modern pinnate types. 

Occurrence: Latah formation, cut along Spokane1 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Populus fairii Knowlton, n. sp. 

Pla.tP. XV. Fillure 2: Plate XVI, Figures 1-3 

Leaves evidently coriaceous, large (8 to 12 centir 

meters broad, 6.5 to 8 or 9 centimeters long), from 

nearly circular to very broadly ovate, truncate, or 

slightly heart-shaped at the base, obtuse and rounded 

at the apex; margin entire below, with three or four 

large, obtuse lobes on each side separated by shallow r 
FLORA OF THE LATAH FORMATION 31 

sinuses; petiole stout, at least 4 centimeters long; 

nervation palmately five-ribbed from the top of the 

petiole; midrib with two or three pairs of thin, alternate, often irregular secondaries above the middle of 

the blade, which arch around nearly or quite to the 

midrib in the upper part; lateral ribs nearly as strong 

,... as the midrib, arising at an angle of 40° or 50°, much 

curved upward and joining the lowest pair of secondaries on the midrib, each with several tertiary branches 

on the outside, these mainly arching around and 

each joining the one next above; lowest pair of ribs 

(these are virtually basal secondaries on the lateral ribs 

which arise with the ribs at the top of the petiole) 

thin, usually at right angles to the midrib, occasionally 

stronger (as shown in Pl. XVI, fig. 3), nearly as 

strong as the other pair of ribs; nervilles thin, broken, 

breaking up into the finer quadrangular-areolations ......... 

This form is represented by five leaves, four of 

which are figured. They were found in association 

with the numerous leaves of Populus heteromorpha, and 

it is possible that they should be referred to that 

species, but they are so very much larger and show so 

strongly marked a tendency toward five ribs instead 

of three- that it hardly seems as if they could be that 

species, especially as there are no intermediate forms. 

They are certainly closely related toP. heteromorpha, 

however, and subsequent collections may show them 

to intergrade in size and nervation. 

I take pleasure in naming this species in honor of 

Mr. Henry Fair, of Spokane, Wash., who assisted in 

collecting these and many other excellent specimens. 

Occurrence: Latah formation, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, March, 

1922. 

Populus lindgreni K:~towlton 

Plate XIV, Figures 4-7 

Populus lindgreni Knowlton, U. S. Geol. Survey Eighteenth 

Ann. Rept., pt. 3, p. 725, pl. 100, fig. 3, 1898; U. S. 

Geol. Survey Bull. 204, p. 29, pl. 2, fig. 1, 1902. 

The type of this species came from the Payette formation near Marsh post office (now Montour), Boise 

County, Idaho. A single example was subsequently 

found in the Mascall formation of the John Day Basin, 

Oreg. The material from Coeur d'Alene includes 

four finely preserved leaves, all of which have been 

figured, as well as several les~ : perfect specimens. 

These specimens permit a revisic1n or amplification of 

the description. In the type specimen there are five 

ribs that arise at the top of the petiole, the second 

pair being by far the stronger. In the new specimens 

there are three principal ribs, the lateral ones with 

several secondary branches on the outside. In some 

specimens the first pair of secondaries arise from the 

ribs at or near the base, thus appearing to be fiveribbed, but in .most specimens the first secondaries 

arise a short distance above the base. The lowest 

pair of secondaries in the broader leaves have several 

tertiary branches that supply the lower portion of the 

blade. Many of the upper secondaries on the midrib 

as well as the lateral ribs and the secondary and tertiary branches from them are forked, the ultimate 

branches ending in the marginal teeth. The nervilles 

are strong, mainly broken and irregular, some of them 

not reaching across the space between the major 

nervation. 

It is now evident that there is a considerable range 

in size and in the shape of the base of this species. 

The smallest leaf found (fig. 7) is 4.5 centimeters long 

and 4.5 centimeters wide; it has the petiole preserved 

for a length of 1.5 centimeters. The next in size (fig. 5) 

is a little more than 6 centimeters long and is 7 centimeters broad. The one shown in Figure 4 is about 

6.75 centimeters wide and 6.5 centimeters long. The 

largest specimen (fig. 6) is fully 8 centimeters broad 

and nearly 8 centimeters long. 

It will be seen that two of the specimens figured are 

practically truncate at the base, but a third (fig. 5) is 

slightly and the fourth (fig. 6) markedly heart-shaped 

at the base. In all the specimens the margin is finely 

and evenly undulate-toothed. In one of the specimens 

(fig. 5) there is a slight lobe on one side in which the 

lateral rib terminates. 

· Among living forms this appears to approach most 

closely the European Populus tremula or its American 

relative P. tremuloides Michaux, especially in marginal 

dentation, but they differ considerably in shape. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Populus washingtonensis Knowlton, n. sp. 

Plate XV, Figure 1 

Leaf thick and coriaceous, nearly circular, broadly 

truncate at the base and rounded obtuse at the apex; 

margin with few large, low, rounded lobes; petiole very 

stout, probably flattened; nervation pinnate, the midrib straight, very thick below, thin above, with about 

five pairs of strong, opposite, parallel secondaries, the 

lowest pair arising at the top of the petiole and thus 

simulating a three-ribbed appearance; the lowest pair 

of secondaries with three or four tertiary branches and 

the middle secondaries with two or three branches, 

which terminate in the margin; nervilles rather sparse, 

mainly broken; finer nervation not well retained. 

This species is represented only by the specimen 

figured. It is about 6.5 centimeters long and nearly 

8 centimeters wide; the petiole is 2.5 centimeters 

long and was either flattened or was thick and fleshly 

and has been crushed flat. It is fully twice the thickness of the base of the midrib. 

This leaf was found in association with leaves of 

Populus lindgreni and may be an extreme form of it, 

but the differences are so many and so marked that 

the leaves must seemingly be separated. Thus in 
32 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

place of the evenly and finely undulate-toothed 

margin of P. lindgreni we have the few large 

rounded lobes with entire margins in P. washingtonensis. The nervation in P. washingtonensis is 

more strict and more obviously pinnate than it is in 

P. lindgreni, and the petiole is obviously stouter. 

The margin in P. washingtonensis is most like the 

margin of the living P. grandidentata Michaux; the 

shape of the leaf is different. It does not approach 

very closely any fossil form described from the region. 

· Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene~ Idaho, collected by H. J. Rust, 

July, 1920. 

Salix elongata 0. Weber 

Plate XII, Figure 4 

Salix elongata 0. Weber, Palaeontographica, vol. 2, p. 177, pl. 

19, fig. 10, 1852. 

Lesquereux, U. S. Geol. Survey Terr. Rept., vol. 7 (Tertiary flora), p. 169, pl. 22, figs. 6, 7, 1878. 

Knowlton, U. S. Geol. Survey Mon. 32, pt. 2, p. 698, 1899. 

The leaf here figured, which is absolutely perfect, 

appears to be the same as specimens from Elko, Nev., 

identified by Lesquereux as Salix elongata 0. Weber. 

Whether or. not they are correctly referred to the 

European species is a question that need not be 

answered at this time. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Salix perplexa Knowlton 

Plate XII, Figure 5 

Salix perplexa Knowlton, U. S. Geol. Survey Bull. 204, p. 31, 

pl. 2, figs. 5-8, 1902. 

Chaney, Am. Jour. Sci., 5th ser., vol. 4, p. 216, 1922~ 

The specimen figured agrees well with one of the 

figured types of this somewhat variable species. This 

species is very abu.ndant in the Mascall formation 

of the John Day Basin, and recently Chaney has 

found it in the Payette formation of western Idaho. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Salix dayana Knowlton 

Plate XII, Figures 1, 2 

Salix dayana Knowlton, U. S. Geol. Survey Bull. 204, p. 31, 

pl. 2, figs. 9, 10, 1902. 

There are several specimens that appear to belong 

to this species. Of the two examples illustrated the 

one seen in. Figure 1 is the under side of the leaf, 

showing the finely reticulated ultimate nervation. 

The other (fig. 2) shows the upper side of the leaf 

and the disposition of the secondaries. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Salix remotidens Knowlton, n. sp. 

Pia te XII, Figure 7 

Leaf of finer texture, lanceolate, 11 centimeters 

long, 2. 7 centimeters wide, broadest below the middle, 

thence tapering to the obtuse base and above to a 

long, slend~rly acuminate apex; margin. entire for the 

lower and upper thirds of the blade, ~he middle third 

with a few very small, blunt teeth; petiole stout, 1.5 

centimeters long; midrib moderately strong for the 

size of the blade, straight; secondaries ·12 or 15 pairs, 

thin, mainly alternate, the basal pair opposite, at an 

angle of about 45°, the others nearly at a right angle, 

all much curved upward and running for a considerable 

distance near the margin; in the lower and middle 

portions of the blade there are a few intermediate 

secondaries; finer nervation obscure. . 

This leaf appears to be very well · char~cterized by 

the few, blunt teeth in the middle of the blade, but 

in size, shape, and nervation it is so characteristically 

a willow leaf that it would be difficult to diagnose it so 

that it could be readily distinguished from numerous 

others. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected 

by Henry Fair and C. E. Fernquist, 1922. 

Salix inquirenda Knowlton, n. sp. 

Plate XI, Figures 1, 2 

Leaves firm in texture, large, lanceolate-acuminate, 

rather abruptly rounded at base, long and slenderly 

acuminate at apex; margin evenly toothed throughout, 

even near the base, the teeth rather remote, some of 

them fairly sharp but most of them blunt and rounded; 

midrib very strong below, very thin above; secondaries 

numerous, arising at· a low angle) some of them almost 

at a right angle, then curving upward along the 

borders and often each joining the one next above and 

sending thin branches, almost nervilles, to the teeth; 

intermediate secondaries between most of the secondaries, especially in. the lower and middle portions of 

the blade; finer nervation producing a fine . irregular 

network. 

This species is represented by several more or less 

perfect leaves, three of which are figured. The 

largest leaf (fig. 2) is nearly 3 centimeters wide and 

has the base well preserved. The others (fig. 1) lack 

the base but have the apex almost complete. The 

lower ·of these two, preserved on the same piece of 

matrix, is about 13 centimeters long and 2.25 centimeters wide. The upper one was at least 12 centimeters long and is nearly 2.5 centimeters wide. 

In size, shape, and nervation .these leaves are so 

characteristic of Salix that the generic reference can 

be considered settled, but decision as to the species is 

quite another matter. Many llving species can not be 

separated by the leaves alone, and many fossil species 

are equally difficult to characterize. 
FLORA OF THE LATAH FORMATIONi 33 

Of the several forms of willow leaves described in 

the present paper the species that seems to be nearest 

to the leaves under discussion is Salix remotidens, 

which has the few remote, blunt teeth confined to the 

middle of the margin, whereas in these the teeth are 

present throughout, although of much the same 

character. Among described species the leaves under 

discussion are very similar in size, shape, and nervation 

to some of the leaves from the Swiss Miocene, described 

and figured by Heer 23 under the name Salix varians 

Goppert, but they differ in the character of the teeth. 

Salix varians Goppert is accepted as present in the 

Mascall formation, as well as in the beds at Ellensburg, 

Wash., the Miocene of the Yellowstone National 

Park, and supposedly in the Kenai formation of 

Alaska. 

Occurrence: Latah formation, Twelfth A venue and 

Thor Street, Spokane, Wash., collected by Henry 

Fair and Kirk Bryan, June, 1923. 

Salix bryani Knowlton, n. sp. 

Plate XII, Figure 6 

Leaf firm in texture, rather narrowly lanceolate, 

apparently acuminate at both base and apex, t~ough 

these parts a~e missing; margin with very small, 

remote, sharp, appressed teeth; midrib very strong, 

especially below; secondaries numerous, probably 15 

or more pairs, alternate, at a low, almost right angle 

in the lower part, at an angle of about 30° in the 

middle and upper part of the blade, all camptodrome, 

each curving and joining the one next above, forming 

an intramarginal "stitch"; finer nervation forming a 

close network of irregularly quadrangular areas. 

The leaf figured must have been about 8 centimeters 

in length when perfect and is 1.5 centimeters wide 

near the middle, whence it narrows in about equal 

degree to base and apex. The secondary nervation 

is characteristical;ly that of Salix. 

This leaf, as regards size and shape, belongs to the 

nondescript type that is very hard to characterize, but 

the_,_ peculiar type of marginal teeth is unusual and 

should make it easy to recognize in future. The 

living Salix discolor Muehlenberg has teeth of this 

kind. 

Occurrence: Latah formation, cut on Chicago, 

Milwaukee & St. Paul Railway near Spokane, Wash., 

collected by Kirk Bryan, June, 1923. 

Salix sp. 

Plate XII, Figure 3 

In the collection from Coeur d'Alene I find this 

little leaf, which appears to be different from any of 

the other Salix leaves. It was evidently rather thin 

in texture, lanceolate, with an apparently rounded 

base and ·probably acute apex. It was 5 centimeters 

in length and nearly 1.5 centimeters in width. The 

2a Beer, Oswald, Flora tertiaria Helvetiae, vol. 2, pl. 65, figs. 1-3, 6--16, 1856, 

margin is entire and slightly undulate. The nervation is delicate, consisting of a thin, straight midrib 

and about 10 pairs of thin, alternate, camptodrome 

secondaries, which arch upward and each joins the 

one next above, often by several large loops. The 

finer nervation produces rather large irregular areolae. 

This form could be compared with a number of 

described species, but the difficulty of establishing 

identity on a single incomplete leaf is . so great that · 

it has seemed best not to assign a specific name. If 

1 more complete leaves are found later it will be an 

easy matter to · name them and characterize them 

more fully. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Order FAGALES 

Family BETULACEAE 

Alnus, pistillate cones 

Plate XVIII, Figures 3-5a 

The two specimens figured are undoubtedly the 

m~ture pistillate aments or "cones" of an Alnus. 

The-shape' and margins of the individual scales can 

not be made out with certainty, but the nutlets 

appear to be ovoid, though the presence or absence 

of a wing can not be determined. 

Among living species these ''cones'' seem to resemble most closely those of Alnus incana (Linne) 

Willdenow, the hoary alder, a species widespread in 

northern North America as well as in Europe and Asia. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill. Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Betula fairii Knowlton, n. sp. 

Plate XVII, Figure 4 

Leaves small, about 23 millimeters long, 13 millimeters wide, apparently coriaceous, elliptical, about 

equally rounded to both base and apex; margin entire 

at the base, thence finely toothed, the teeth somewhat 

irregular, mainly sharp-pointed, the point indurated 

or thickened; nervation strong, especially the midrib; 

there is a thin pair of basal secondaries at right angles 

to the midrib, then about six pairs of alternate secondaries at an angle of' 45°, straight and ending in the 

teeth; nervilles numerous, mainly percurrent and at 

right angles with the secondaries; finer nervation 

abundant, forming an irregularly quadrangular network. 

This little leaf, the only one observed, is absolutely 

perfect, including the petiole. It may be known by 

its elliptical shape with obtuse and rounded apex and 

rounded, almost truncate base, irregularly toothed 

margin, and very · strong nervation. It is most 

closely related to Betula heteromorpha Knowlton,24 

24 Knowlton, F. H., U. S. Geol. Survey Bull. 204, p. 39, pl. 3, figs. 6, 7, 1902. 
34 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

from the upper part of the Clarno formation (Bridge 

Creek locality), from which it differs in its smaller 

size, elliptical shape with rounded and obtuse apex 

and more truncated base, and fewer secondaries. 

This species is named in honor of Mr. Henry Fair, 

of Spokane, who not only collected the type specimen 

but has rendered invaluable aid in collecting throughout the Spokane area. 

Occurrence: Latah · formation, cut on Chicago, 

Milwaukee & St. Paul Railway near Spokane, Wash., 

collected by Henry Fair and Kirk Bryan, June, 1923. 

Betula nanoides Knowlton, n. sp. 

Plate XVIII, Figure 2 

Leaves small,.about 15 millimeters long and 12 millimeters broad, broadly ovate, abruptly rounded and 

slightly heart-shaped at base, almost equally rounded 

above to the acuminate apex; margin finely serrate, the 

teeth sharp-pointed, probably glandular tipped; midrib 

relatively very strong; secondaries six or seven pairs, 

the lowest pair nearly at right angles with the midrib, 

with tertiary branches on the lower side, other secondaries at an angle of about 40°, nearly straight, lower 

and middle ones with one or two branches, all craspedodrome and ending in the teeth; nervilles numerous, 

mainly at right angles to the secondaries, broken or 

percurrent. 

This little ieaf seems certainly referable to Betula. 

The margin is finely serrate, and in addition there is a 

faint indication of its being doubly serrate-that is, 

there are slight projections beyond the general outline 

where the secondaries and their branchlets enter the 

teeth, but they are of little prominence. 

This species does not seem to approach very closely 

any living American birch, perhaps the nearest in 

shape being Betula occidentalis Hooker, but that 

species has leaves 7 or 8 centimeters long that are 

IP.Ore acute at the apex. The European Betula 

humilis Schrank, however, is very similar both in size 

and shape. This is a small shrub from 3 to 6 feet 

high growing on peat bogs in the Tyrol and else~here 

in central Europe, but the leaves are less truncate at 

the base and have fewer and larger teeth, with no 

tendency to be doubly serrate. 

Occurrence: ·Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Betula heteromorpha Knowlton 

Plate XVII, Figures 5, 6 

Betula heteromorpha Knowlton, U. S. Geol. Survey Bull. 204, 

p. 39, pl. 3, figs. 6, 7; pl. 5, fig. 1, 1902. 

Several leaves were noted in the collections that 

must be referred to this species. Except for its 

slightly larger size the larger specimen here figured is 

\ not to be distinguished from the leaf figured on Plate 

V, Figure 1, of my "Flora of the John Day Basm," 

and the smaller one (fig. 5) is the same as Figures 6 

and 7 of Plate III of that work. · 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. 

Rust, July, 1920; cuts on Spokane, Portland & 

Seattle Railway and Chicago, Milwaukee & St. Paul 

Railway, Spokane, Wash., collected by R. W. Chaney, 

1922. Specimen in UniversitJ" of California Museum, 

No. N-M:· 

Betula? largei Knowlton, n. sp. 

Plate XVII, Figures 1, 2 

Leaves large, 12 to 15 centimeters long, 6 to 8 centimeters wide, fairly firm in texture, elliptical or broadly 

ovate-elliptical, abruptly rounded below to a truncate 

or slightly heart-shaped base and above to .an apparently acuminate apex; margin obscurely doubly serrate-that is, the teeth entered by the secondaries are 

slightly larger than the others, of which there are 

usually two or three between two of the larger ones; 

all are sharp-pointed; midrib thick, straight; secondaries 10 or 12 pairs, at an angle of 40°-50°, parallel, 

nearly straight, entering the larger teeth; nervilles 

rather sparse, mainly unbroken and ~t right angles 

to the secondaries, finer nervation producing a fine 

network between the nervilles. · 

This form is represented by several leaves, two of 

the best of which are figured. I am uncertain as to the 

generic reference. There is some resemblance to certain living leaves of Alnus and Oorylus, but altogether 

they agree best with larger leaves of Betula, such as 

especially long, slightly heart-shaped leaveF' of Betula 

papyrifera Marshall. However, considering the uncertainty the generic reference has been questioned. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922; well 

at Mica, Wash., southeast of Spokane, collected by 

Thoma,s Large for J. T. Pardee, August, 1922. 

Betula bryani Knowlton, n. sp. 

Plate XVIII, Figure 1 

Leaf thin, ovate-elliptical, abruptly rounded below 

to the slightly heart-shaped base, apparently acuminate 

at the apex; margin entire at the base, then strongly 

toothed, the teeth entered by the secondaries slightly 

larger than the two or three intermediate ones, all 

deltoid in shape; midrib strong; secondaries six pairs . 

alternate, at an angle of about 45°, very little curved 

upward, craspedodrome, entering the larger teeth; 

nervilles numerous, mostly simple and at right angles 

to the secondaries; finer nervation producing a fine 

quadrangular network. 

The little leaf figured is the only one noted in the 

collections. It is about · 5.5 centimeters long and 

nearly 3.5 centimeters wide. It is not exactly doubly 
FLORA OF THE LATAH FORMATION 35 

serrate, though there is a tendency for the teeth entered by the secondaries to be slightly· larger than 

the intermediate ones. Among living species it 

seems to approach most closely certain of the 

broader, heart-shaped forms of Betula papyrijera 

Marshall, the well-known canoe or paper birch. The 

teeth, however, are not so sharp-pointed as in most 

living species of Betula. The species is named in 

honor of Mr. Bryan. 

Occurrence: Latah formation, Twelfth Avenue and 

Thor Street, Spokane, Wash., collected by Henry 

Fair and Kirk Bryan, 1923. 

Betula thor Knowlton, n. sp. 

Plate XVII, Figure 3 

Leaf of medium size, about 6.5 centimeters long 

and 4 centimeters wide, with a petiole at least 2 centimeters long, membranaceous, ovate, very obtusely 

wedge-shaped at the base and acuminate at the apex; 

.margin entire at base, then distinctly doubly serrate, 

_the teeth sharp, pointing upward; petiole and midrib 

stronO'; secondaries eight or nine pairs, alternate, at an 

angleb of about 40°, straight, parallel, ending in the 

larger teeth, and usually with two or three light 

branches which enter the smaller teeth; nervilles 

numerous, thin, irregular, mainly oblique to the 

secondaries; finer nervation producing an intricate, 

fine network. 

Among living American species the present species 

appears to approach most closely certain of the narrower, more normal leaves of Betula papyrifera Marshall, the common paper birch, which ranges widely 

from Labrador, the southern shores of Hudson Bay, 

and Great Slave Lake westward to Montana and 

northwestern Washington, though not very abundant 

in the Rocky Mountains. 

Among fossil species known from the general region 

Betula thor shows points of agreement with several. 

Thus, Betula heteromorpha Knowlton,25 from the 

upper part of the Clarno formation at Bridge Creek, 

Oreg., agrees in size, but its marginal teeth are almost 

invariably rounded instead of sharp, and it is less 

obviously doubly serrate. 

The species described above under the name Betula 

bryani is from the same locality as the present species, 

but it is distinctly heart-shaped at the base and has 

the teeth deltoid instead of sharp-pointed; it is also 

less obviously doubly serrate. If a series of leaves 

were available from this locality it might show these 

two forms to be the same, but as at present known 

they seem to be quite distinct. It may be that these 

correspond to the type and the variety cordifolia of 

Betula papyrifera. 

Occurrence: Latah formation, Twelfth Avenue and 

Thor Street, Spokane, Wash., collected by Henry Fair 

and Kirk Bryan, 1923. 

2.1 Knowlton, F. H., U. S. Geol. Survey Bull. 204, p. 39, vol. 3, figs. 6, 7; pl. 5, 

fig. 1, 1902. 

Carpinus sp. 

This specimen is a fragment of what appears to be 

a leaf of Carpinus. It is a small leaf, apparently between 6 and 7 centimeters in length and a little over 

2 centimeters in width. It is lanceolate, apparently 

long wedge-shaped ·at the base and narrowly, acuminate at the apex. The margin is sharply doubly serrate, though the distinction between the major ~eeth, 

or those entered by the secondaries, and the Intermediate teeth is not very pronounced. The number 

of secondaries can not be made out ftom this fragmentary specimen, but there must have been 10 or 12 

pairs. They are close, parallel, at an angle of 45 ° or 

50°, and nearly straight. The nervilles are ~umerous, 

rather strong, at right angles to the secondanes·. 

This specimen is so fragmentary that it can not be 

compared very successfully with other forms. It is 

nearest to the living Carpinus carolinensis Walter but 

is apparently longer and narrower. In some particulars it agrees with Alnus carpinoides Lesquereux, 26 from 

Bridge Creek, Oreg., but that is a much larger species 

and has the margin much more pronouncedly doubly 

serrate. The present specimen is also similar to certain of the smaller, narrower leaves of Carpinus grand is 

Unger, such for instance as some of those figured by 

Heer 27 from the Miocene of Sakhalin. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Castanea castaneaefolia (Unger) Knowlton 

Plate XVIII, Figures 7, 8; Plate XIX, Figure 1 

Castanea castaneaefolia (Unger) Knowlton, U. S. Geol. Survey 

Bull. 152, p. 60, 1898. 

Castanea ungeri Heer: Lesquereux, U. S. Geol. Survey Terr. 

Rept., vol. 8 (Cretaceous and Tertiary floras), p. 246, 

pl. 52, figs. 3-7, 1883. 

These specimens agree with those previously 

reported from the John Day Basin, Oreg. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Quercus merriami Knowlton 

Plate XIX, Figures 4, 5 

Quercus merriami Knowlton, U.S. Geol. Survey Bull. 204, p. 49 

pl. 6, figs. 6, 7; pl 7, figs. 4, 5, 1902. 

Quercus pseudo-lyrata an. gustiloba Lesquereux, U. S. Nat. Musl 

Proc., vol. 11, p. 17, pl. 11, fig. 2, 1888. 

The nearly perfect leaf figured is not to be dis 

tinguished from the smaller of the leaves figure 

among the types of Quercus merriami Knowlton, excep 

that the teeth are not quite so sharp-pointed. Th 

tip of a leaf shown in Figure 4 has the teeth bristlej 

26 Lesquereux, Leo, U. S. Geol. Survey Terr., vol. 8 (Cretaceous and Tertiar 

floras), p. 243, pl. 50, fig. 11; pl. 51, figs. 4, 5, 1883. 

21 Heer, Oswald, Flora fossilis arctica, vol. 5, Abt. 4, pl. 8, figs. 3, 4, 6; pl. 9, fi 

1, !:!, 1878. 
36 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

pointed, as in the types, though the teeth are not quite 

so large. · 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Quercus cognatus Knowlton, n. sp. 

Plate XX, Figures 1-4; Plate XXI, Figures 1, 2 

Leaves variable in size, coriaceous, lanceolate or 

elliptical-lanceolate, rather obtusely wedge-shaped at 

the base, moderately acute at the apex; margin entire 

for a short distance at the base, then provided with 

6 to 10 large teeth separated by rounded sinuses; the 

lower teeth are the smaller and are usually rounded; 

the upper ones are the larger and usually sharp-pointed; 

petiole strong; midrib very strong; secondaries strong, 

straight, mainly alternate, as many as the teeth and · 

entering them; nervilles numerous, strong, mainly 

broken, forming with the smaller veins a fine network. 

This is one of the most abundant species in the collections, being represented by not less than 25 more · 

or less perfect leaves. The largest specimen (Pl. XX, 

fig. l) must have been at least 18 centimeters in length 

exclusive of the petiole, which is 1.5 centimeters long; 

its greatest width is 6.5 centimeters. The next size 

(Pl. XX, fig. 2) was probably about 13 or 14 centimeters long and only 4 centimeters wide. A nearly 

similar example (Pl. XXI, fig .. 1) was i 1 or 12 centimeters long and about 4.5 centimeters wide. This 

specimen, which has somewhat sharper lobes than 

those already mentioned, has a petiole 2.5 centimeters long. The one shown in Figure 1 of Plate XXI 

has all the lobes sharper pointed than the majority. 

Still another specimen was only about 10 centimeters 

long. Plate XX, Figure 3, shows the nearly complete 

apical portion. 

At first it was presumed that these Spokane leaves 

could be referred to one of the forms of the polymorphous Quercus psewlo-lyrata Lesquereux, which 

is so abundant in the Mascall formation of the John 

Day Basin, but a careful comparison convinces me 

that they are not identical. Some of the Spokane 

leaves approach more closely what has been segregated as Quercus merriami Knowlton, 28 but that species 

differs so much that they can not be placed together. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920 (Pl. XX, fig. 3); Spokane, Wash. 

Quercus cf. Q. pseudo-lyrata Lesquereux 

Plate XXII, Figure 2 

The specimen here figured, a mere fragment, is all 

that was noted of this form. It was a large leaf 

probably not less than 15 centimeters long and 8 or 9 

centimeters wide. The margin is very deeply cut 

28 Knowlton, F. H., U.S. Gool. Survey Bull. 204, p. 49, pl. 6, figs. 6, 7; pl. 7, figs. 

4, 5, 1902. 

into probably three or four large, upward-pointing, 

rather acute· lobes. The .sinuses between the lobes 

are very deep and rounded. The nervation is preserVed with remarkable fidelity and is well shown in 

th~ figure. The midrib is very strong and shows 

little diminution within the fragment present. The 

secondaries are also strong; they pass nearly straight 

well into the lobes and then turn slightly upward. 

The intermediate secondaries are numero:us, at irregular distances, and of ·various sizes, all nearly at right 

angles with the midrib and mimptodrome, arching for 

considerable distances just inside the margin, .especially around the sinuses. The finer nervation is 

irregularly quadrangular. 

This leaf is of the type of Quercus lyrata Walter 

and in fact may be a large leaf of Quercus psewlolyrata Lesquereux, 29 which is an abundant form in the 

Ma8call formation of the John Day Basin. It would 

probably do no great violence to identify this leaf 

directly with Lesquereux's species, but as it is so frag- · 

mentary it seems best to question the determination. 

Quercus psewlo-lyrata is probably . more closely related to Quercus velutina Lamarck and Quercus californica Cooper; the latter is the largest and most 

abundant species of the valley of southwestern Oregon 

and of the Sierra Nevada. 

Occurrence: Latah formation, 1 mile west of Shelley 

Lake, half a mile south of "Apple Way," and about 

10 miles east of Spokane, Wash., collected by Henry 

Fair, October, 1922. \ 

Quercus rustii Knowlton, n. sp. 

Plate XXI, Figures 3, 4 

Leaves 'evidently cotiaceous, lanceolate, narrowed 

from a point near or above the middle to the long 

wedge-shaped base and prolonged above into a slender, acuminate apex; margin with three remote, rather 

small, sharp-pointed teeth on each side; · the teeth are 

separated by long, shallow sinuses; petiole short, stout; 

midrib very .strong for the lower half of the blade, 

thence greatly reduced; secondaries 10 or 12 pairs, at 

an angle of 60° or 70°' the lower ones curving along 

the margin, those in the middle and upper part 

remote, entering the teeth; finer nervation producing 

a fine quadrangular· network. 

The best preserved of these leaves (fig. 3) is 10 

centimeters long and about 2.5 centimeters wide. 

The other one figured (fig. 4) was probably nearly 

12 centimeters long and about 3.5 centimeters wide 

between the points of the largest teeth. 

This species is probably most closely related to 

Quercus payettensis Knowlton but differs in -the long 

wedge-shaped base, _ the fewer, _remote teeth, and the 

slenderly acuminate apex. This species is also very 

similar to certain of the narrower leaves of Quercus 

29 Lesquereux, Leo, Harvard Univ. Mus. Comp. Zoology Mem., vol. 6, pl. 2, 

figs. 1, 2, 1878. . . 
FLORA OF THE LATAH FORMATION. 37 

nerriami Knowlton 30 but differs in having fewer and 

.mailer lobes and in the peculiar wedge-shaped base. 

The species is named in honor of Mr. H. J. 'Rust, 

\Tho collected all of the splendid material from the . 

Joeur d'Alene locality. 

Occurrence: Latah formation, Edwards ranch, Staney Hill, Coeur d'Alene, Idaho, collected by H. J. Rust., 

ruly, 1920. 

Quercus spokanensis Knowlton, n. sp. 

Plate XIX, Figure 3 

This form is represented by the single specimen 

igured, which is the upper portion of a leaf that is now 

kbout 8 centimeters long but must have been 12 

:entimeters or more when complete. It is 6 centineters wide in the middle. It appears to have been 

:lliptical or possibly slightly obovate-elliptical. The 

nargin is almost undulate-toothed, or in any event 

he teeth are regular, obtuse or very obtusely pointed, 

,nd separated by shallow sinuses. The midrib is 

noderately strong, and the secondaries are regular, 

.venly spaced, alternate, and as many as the marginal 

eeth, which they enter. The finer nervation is 

rregularly quadrangular and distinctly quercoid in 

,ppearanqe. 

This species is quite unlike any of the other oaks 

rr the collections. It is of the type of a group of 

[ving species which includes Quercus michauxii 

~uttall, Q. prinus Linne, Q. acuminata Sargent, and 

·thers. 

Among fossil species this is very close to Quercus 

owlesi Chaney,31 from the Eagle Creek formation of 

ll:ultnomah County, Oreg.-in fact, it may be idenical with that species. However, Quercus cowlesi has . 

ewer, less prominent teeth and fewer, less regular 

econdaries. A series of specimens might well enough 

how these comparatively slight differences breaking 

.own. 

Occurrence: Latah formation, cut along Spokane, 

>ortland &. Spokane Railway, Spokane, Wash., 

ollected by Henry Fair and C. E. Fernquist, 1922. 

Quercus payettensis Knowlton 

Plate XXI, Figures 5-7 

uercus payettensis Knowlton, U. S. Geol. Survey Eighteenth 

Ann. Rept., pt. 3, p. 730, pl. 102, fig. 9, 1898. 

This species was based on a leaf froni the Payette 

)rmation of Idaho that lacks both base and apex but 

:well characterized by its lanceolate outline and large 

eltoid teeth. None of the nervation is preserved 

x:cept the midrib and secondaries. 

The collection from Coeur d'Alene, Idaho, includes 

~veral specimens that, though slightly larger, must 

e referred to Quercus payettensis. The best preso Knowlton, F. H., U.S. Geol. Slirvey Bull. 204, p. 49, pl. 6, figs. 6, 7, 1902. 

a1 Chaney, R. W., Chicago Univ. Walker Mus. Contr., vol. 2, No. 5, p. 169, pl. 

' fig. 5, 1920. 

served example, shown in Figure 7, is nearly perfect. 

I tis long wedge-shaped at the base and rather abruptly 

deltoid pointed at the apex. It is 7 centimeters long 

and about 2.5 centimeters wide. Another specimen 

(fig. 5) is also nearly perfect. It shows the wedgeshaped base with one or two very small teeth, and 

in the ;rniddle of the leaf are the strong teeth, one of 

w.hich is distinctly spine-tipped. The other specimen 

figured (fig. 6) is a segment from the middle of a leaf 

that must have been at least 10 centimeters long; 

it is nearly 3.5 centimeters wide between the points 

of the lobes. This is precisely the same as the type, 

except for its larger size. 

O<(currence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

(luercus sp. 

Plate XIX, Figure 7; Plate XXII, Figure 9 

Leaves coriaceous, ovate or ovate-elliptical; very 

obtusely wedge-shaped at the base, obtusely pointed 

at the apex, with two or three large, obtusely acuminate lobes ori each side; midrib strong, more or less 

irregular and zigzag; principal secondaries as many as 

the lobes, at a low angle, .much curved upward toward 

the margin; intermediate secondaries numerous, at 

irregular distances and angles, curving upward and 

disappearing along the margin; nervilles numerous, 

strong, irregular, mainly broken; finer nervation 

strong, irregularly quadrangular. 

The two figured specimens are referred to this 

form. The larger one (Pl. XIX, fig. 1) was probably 9 or 10 centimeters long and 7 centimeters wide 

between the largest lobes. The other specimen 

(Pl. XXII, fig. 7) is 8 centimeters long and 5 centimeters wide. 

This species seems to be quite distinct from the 

other forms found in these beds, though it may 

possibly be represented by somewhat distorted or · 

abnormal leaves of one of the common forms. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Quercus praenigra Knowlton, n. sp. 

Plate XIX, Figure 6 

Leaf coriaceous, narrowly obovate, broadest above 

the middle, whence it is gradually narrowed to an 

abruptly rounded base; margin perfectly entire; 

petiole very stout; midrib very strong; secondaries 

mainly alternate, thin, at irregular distances, arising 

at a low angle (about 20° or 25°), much curved upward along the margins; nervilles mainly oblique to 

the secondaries, broken and irregular, and forming 

with the finer nervation a complicated network. 

The incomplete specimen figured is the only one 

noted in the collectioJ;l.S. It probably lacks the upper 
38 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

third and when perfect was presumably about 14 

centimeters long. It is about 4.5 centimeters · wide 

at the point where it is broken, and the missing 

portion was probably 5 centimeters or slightly more 

in width. Only a short portion of the thick .petiole 

is retained. 

This leaf is quite distinct from the other oaks of 

the collec-tion; but among living species it seems 

fairly close to Quercus nigra Linne, the water oak 

of the eastern and southern United States. It is 

somewhat more · obtuse at the base but otherwise is 

very similar. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. ~ust, 

1920. . 

Quercus simulata Knowlton 

Plate XXII, Figures 3, 4 

Quercus simulata Knowlton, U. S. Geol. Survey Eighteenth 

Ann. Rept., pt. 3, p. 728, pl. 101, figs. 3, 4; pl. 102, 

figs. 1, 2, 1898; 

Chaney, Chicago Univ. Walker Mus. Contr., vol. 2, 

No. 5, p. 168, pl. 12, fig. 1, 1920. 

This species is represented by several examples, 

two of which have been figured. These, it will be 

seen, agree perfectly with the entire-leaved specimens 

from the type locality-that is, the Payette formation 

of Marsh, Idaho. In the type specimens the finer 

nervation was not well preserved, but in the present 

specimens it is perfectly retained. It is well shown 

in Figure 4. 

A poorly ._preserved leaf found in the Eagle Creek 

formation of the gorge of Columbia River, Oregon, 

has been identified as Quercus simulata by Chaney. 

It has more marginal teeth than any of the type 

specimens, and the details of nervation are missing. 

Occurrence: Latah formation, Deep Creek half a 

mile above mouth and cut along Spokane, Portland & 

Seattle Railway, Spokane, Wash., collected by Henry 

Fair and C. E. Fernqu.ist, 1922. 

Quercus chaneyi Knowlton, n. sp. 

Plate XXII, Figure 1 

This interesting species is well represented by the 

little leaf figured, which fortunately is nearly perfect. 

It was evidently very thick and coriaceous and is 

narrowly lanceolate, being slightly broader at a point 

about one-fourth its length from the apex. It was 

about 9 centimeters long and 1.5 centimeters wide, 

with the petiole preserved for a length of 0.5 centimeters, but is evidenhly not complete. From the 

broadest point in the blade it narrows gradually abov~ 

to. what was apparently an obtusely acuminate apex 

and downward to a long, narrow basal portion. The 

margin is entire or slightly undulate for the lower twothirds and thence with four or five teeth on each side, 

these low and rounded below but one or two sharppointed higher up.. These teeth are so small that they 

are hardly perceptible to the naked eye, though they 

are plain enough under a glass. The midrib is very 

thick and strong and is perfectly straight, but the 

secondaries are thin and immersed in the leaf substance. The secondaries number about 12 pairs. 

They arise at an angle of 40° or 45° and .. .are close together in the lower part of the blade but remote in the 

upper part. They curve upward for a long distance, 

each usually joining the one next above and sending a 

thin branch to one of the marginal teeth or slight 

swellings. The nervilles are inconspicuous, being 

immersed in the' leaf substance; they are mainly percurrent. The finer nervation is peculiar in that it 

forms a complete network of small, equal-sized arms. 

This leaf is probably correctly referred to Quercus. 

At first glance its shape might suggest a leaf of Salix; 

and the peculiar netlike finer nervation is very much 

like that of certain lauraceous typ~s, such as Persea, 

but the thick substance of the leaf and the few, small 

marginal teeth point to Quercus. It appears to belong 

to the group of so-called live oaks, in which the old 

leaves persist until the spring of the next year. It is 

perhaps closest to Quercus virginiana Miller, though 

longer and narrower than most leaves of that species. 

Among fossil American species Quercus chaneyi 

most closely resembles Quercus simplex Newberry/2 

from the upper part of the Clarno formation of the 

John Day Basin, Oreg., and it has also been reported 33 

from the Raton formation of northeastern New Mexico 

. and southeastern Colorado. It differs, however, in 

being longer and narrower, broadest above instead of 

below the middle, in the sparsely toothed instead of 

entire margins, and in the netlike, finer nervation. 

I take pleasure in naming this species in honor of 

Dr. Ralph W. Chaney, of the Carnegie Institution 

of Washington, who collected a part of this Spokane 

material. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Quercus obtusa Knowlton, n. sp. 

Plate XXII, Figure 8 

Leaf small, about 5.5 centimeters long and 2 cen'tieters broad, coriaceous, obovate-lanceolate, broadest in the upper third, whence it rounds above to an 

obtuse apex · and below to a long, regularly wedgeshllped base; margin entire except very near apex, 

where there are two or three small, sharp-pointed teeth; 

petiole very strong; midrib exceptionally strong, per ... 

fectly straight; secondaries about 12 pairs, mostly 

alternate, thin, immersed, slightly curved upward, 

camptodrome, arching well inside the margin, each 

joining the one next above ·and sending an outside 

nerve to one of the teeth; nervilles fairly numerous, 

83 Newberry, J. S., U. S. Geol. Survey Mon. 35, p. 78, pl. 43, fig. 6, 1898. 

88 Knowlton, F. H., U.S. Geol. Survey Prof. Paped01, p. 298, pl. 70, fig. 3, 1918. 
FLORA OF THE LATAH FORMAT'ION 39 

n, approximately at right angles to the secondaries, 

egular but mainly percurrent; finer nervation 

·ming a fine, irregularly quadrangular network, 

eply immersed. 

This species seems to be quite distinct from any 

1er found ilil the collections from the Spokane area 

from the Pacific coast region. It was evidently a 

[ck, coriaceous leaf, probably an evergreen leaf of 

3 type of Quercus virginiana Miller-in fact, it is 

ite like some of the leaves of this somewhat variable 

3cies. 

Occurrence: Latah formation, cut along Spokane, 

·rtland & Seattle Railway, Spokane, Wash., col-

:ted by Henry Fair -and C. E. Fernquist, 1922. 

Quercus, cup 

Plate XXI, Figure 10 

The collections contain a number of acorn cups, 

t most of them are so crushed that it is impossible 

make out any satisfactory characters. The present 

3cimen, however, is very well preserved and shows 

3 arrangement and shape of the scales clearly. 

Lis cup appears to belong to the white-oak group, 

d there is some evidence to show that the acorn 

s practically immersed, as in the living Quercus 

·ata, but this is not certain. It was of course the 

Lit of one of the species characterized from the 

LVes, but there is no means of connecting them. 

Occurrence: La.tah formation, Edwards ranch, Stanr Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

ly, 1920. 

Quercus, acorn 

Plate XIX, Figures 8, 9; Plate XXI, Figures 8, 9 

This is clearly the impression of a small acorn. 

is ovoid, with a rather broad, truncated base. The 

1gth is about 12 millimeters and the width or 

:tmeter about 7 millimeters. There are no prounced surface markings. 

This is presumably the fruit of one of the forms 

scribed from the leaves, but as there is no way of 

nnecting them, it is best retained as above. 

Occurrence: Latah formation, cut on Spokane, 

>rtland & Seattle Railway, Spokane, Wash., col-

~ted for and submitted by the Spokane Public 

useum. 

Order URTICALES 

Family ULMACEAE 

Ulmus speciosa Newberry 

Plate XVIII, Figure 6 

:mus speciosa Newberry, U. S. Nat. Mus. Proc., vol. 5, p. 

507, 1883; U. S. Geol. Survey Mon. 26, p. 80, pl. 45, 

figs. 3, 4, 1898. 

The specimen figured is the only one noted in these 

•llections. It is nearly perfect, being about 12 

:ntimeters long and 5.5 centimeters wide. The 

argin is not as well preserved as could be desired, 

but so far as can be noted the teeth are large, sharppointed, and with only a few secondary teeth. Many 

of the teeth are without a trace of a smaller taoth, 

and those present are only very slight projections. 

The secondaries, of which t~ere are about 15 pairs, 

are both opposite and alternate, close, parallel, and 

ending in the teeth. The nervilles are numerous, 

somewhat irregular but mainly percurrent, and at 

right angles to the secondaries. The finer nervation 

forms an irregular fine-meshed, quadrangular areolation. 

I do not see how this leaf can be held distinct from 

the larger of the leaves referred by Newberry to his 

mmus speciosa, from Bridge Creek, Oreg. Newberry 

described his species as doubly serrate, but in the 

figures he gives only a few of the teeth near the middle 

of the leaf have additional smaller denticulations, 

thus agreeing with the Spokane leaf. mmus speciosa 

was reported by Penhallow 34 from beds supposed to 

be of Oligocene age in British Columbia. 

This species is of the same type and, indeed, is-very 

closely related to Ulmus pseudo-fulva Lesquereux,35 

from the auriferous gravels of California, and ' also 

reported from the Miocene of Lamar River, Yell owstone National Park. It is a smaller leaf-8.5 centimeters lon(J' and 3.5 centimeters wide-than the leaves 0 

now referred to mmus speciosa and is also described 

as being doubly serrate, b~t the secondary teeth are 

an inconspicuous feature. If a series of specimens 

from California and Oregon and Washington could be 

assembled it might well enough be shown that these 

supposed distinct species should really be merged. 

mmus tanneri Chaney 36 also belongs to this groupin fact, it is in part based on two of the smaller leaves 

of mmus speciosa as figured by Newberry. It is still 

smaller than mmus pseudo-julva Lesquereux but does 

not greatly differ otherwise. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway west of Latah Creek, 

Spokane, Wash., collected by Henry Fair and C. E. 

Fernquist, 1922. 

Ulmus fernquisti Knowlton, n. sp. 

Plate XIX, Figure 2 

Leaf small, about 4.5 centimeters long, 1.5 centimeters wide, evidently coriaceous, lanceolate, slightly 

unequal-sided at the base, acuminate at the ape~; 

margin coarsely and simply dentate, the teeth deltmd 

and large for the size of the leaf; petiole about 5 

millimeters long; midrib straight, very strong; secondaries about 16 pairs, mostly opposite, close, parallel, little curved upward, each ending in a marginal 

· tooth; finer nervation not retained. 

34 Penhallow, D. p ., Report on the Tertiary plants of British Columbia, p. 94, 1908. 

a~ Lesquereux, Leo, Harvard Univ. Mus. Comp. Zoology Mem., vol. 6, No.2, 

p. 16, pl. 4, fig. 3, 1878. 

36 Chaney, R. w., Chicago Univ. Walker Mus. Contr., vol. 2, No.5, p.172, pl.14, 

figs. 1; 2, 1920. 
40 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

This little leaf, the only one noted in the collections, 

seems to belong to mmus, but it differs from most of 

the elms in having the margin simply instead of 

doubly serrate. All the living American species are 

doubly serrate, but some of the European forms are 

simply serrate. It also resembles Planera in that the 

leaves are simply serrate, but the general facies is 

more that of mmus. 

Several long, narrow leaves. representing species of 

mmus from this region have been described, but they 

all differ in being conspicuously doubly serrate. Thus 

mmus tanneri Chaney,37 from the Eagle Creek 

formation of Oregon, is a small-leaved species but is 

much larger and broader than tl...e one from Spokane 

and moreover is doubly serrate. The smaller of the 

two leaves of mmus californica Lesquereux 38 as 

figured by Lesquereux, from the auriferous gravels 

of California, is very much like the leaf under consideration, being only slightly broader, and furthermore 

it is described as simply serrate. The other type 

speciinen as figured by Lesquereux is very much 

larger and broader than the one just mentioned and 

is of course quite different from the Spokane leaf. 

Although it would perhaps do no great violence to 

refer. this leaf to Ulmus californica, it seems advisable 

to give it a different name pending the collection of 

additional material, with the admission that it is 

very closely related to if not indeed identical with 

Ulmus californica. It is named in honor of C. E. 

Fernquist, the collector. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected 

by Henry Fair and C. E. Fernquist, 1922. 

Family MORACEAE? 

Ficus? washingtonensis Knowlton, n. sp. 

Plate XXV; Plate XXVI, Figures 1-3 

Leaves large, 9 or 10 centimeters wide, 10 or 12 

centimeters long, firm, perhaps coriaceous, broadly 

ovate or nearly circular, equal-sided at the base, 

which is rounded and truncate in most specimens 

but in some very obtusely wedge-shaped, the apex 

apparently rounded and obtuse; the margin is entire 

with one specimen showing a pronounced boss on one 

·side; petiole stout, more than 3.5 centimeters long; . 

, palmately five-ribbed from the top of the thick 

petiole, the midrib much the stronger, with about 

three pairs of camptodrome secondaries in the upper 

part; second pair of ribs strong, at an angle of about 

45°, slightly curved upward, joining the lower pair of 

secondaries on the midrib, each with several branches 

on the outside; lower pair of ribs very slender, at a 

37 Chaney, R. W., op. cit., p. 172, pl. 14, figs. 1, 2. 

as Lesquereux, Leo, Harvard Univ. Mus. Comp. Zoology Mem., vol. 6, p. 15, pl. 

4, fig. 2, 1878. -

right angle or very low angle with the midrib; nervilles 

numerous, irregular, forming a large meshed, irregularsized network. 

This form is represented by four specimens, one 

from the Spokane area and the others from Coeur 

d'Alene. It seems to be congeneric and may indeed be 

conspecific with what Lesquereux called Ficus sordida,S9 

from the auriferous gravels of California, since 

detected in the Miocene of the Yellowstone National 

Park. It is very much to be doubted, however, that 

these leaves were correctly referred to Ficus. Lesquereux compared his species to Ficus gronlandica 

Heer/0 from Greenland, but the resemblance is not 

very close-in fact, Heer's species resembles certain 

forms that have been referred to Populus. 

It has been suggested that these leaves from Spokane and vicinity may be referable to the genus 

Menispermites as established by Lesquereux on leaves 

from the Dakota sandstone. Of the 20 species of 

Menispermites described 9 are found in the Dakota 

and the others in several Cretaceous formations except 

a single species, M. wilcoxensis Berry,41 from the Wilcox 

formation of Louisiana. The typical Cretaceous species of Menispermites are more or less three-lobed or 

with undUlate margins and have the major nervation 

craspedodrome, ending in the lobes or undulations. 

This last-mentioned character clearly excludes the 

leaves under consideration and apparently also Menispermites wilcoxensis, in which all the ribs and secondaries are distinctly camptodrome. The Wilcox species 

may be congeneric with the Spokane leaves. Some 

of the Cretaceous leaves included in Menispermites 

are more nearly circular and distinctly pel tate. These 

have a camptodrome nervation, thus disagreeing with 

the type species of the genus. The whole aggregation seems in need of revision. 

A careful comparison of the Spokane leaves with 

Ficus sordida discloses some differences. Thus the 

California species is somewhat larger, and the lateral 

and basal pairs of ribs have a greater number of secondaries, especially the basal pair, and those are more 

regular. The finer nervation also differs somewhat. 

Although it is probable that those leaves do not 

belong to Ficus, in the absence of any other probable 

generic designation I am_ constrained to refer them to 

Ficus but with a distinct mark of interrogation. They 

are easily recognizable, and when more data are available they can easily be transferred to another genus. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920 (Pl. XXVI, figs. 1-3); Spokane, Wash., 

collected by C. E. Fernquist May, 1922 (Pl. XXV). 

39 Lesquereux, Leo, Harvard Univ. Mus. Comp. Zoology Mem., vol. 6, p.17, pl. 4, 

figs. 6, 7, 1878. 

•o Heer, Oswald, Flora fossilis arctica, vol. 2, No.4, pl. 54, fig. 2, 1869. 

41 Berry, E. W., U.S. Geol. Survey Prof. Paper 91, p. 218, pl. 115, figs. 1, 2; pl. 

116, figs. 2, 3, 1916. 
FLORA OF THE J4TAH FORMATION 41 

Order THYMELALES 

Family LAURACEAE 

Laurus similis Knowlton 

Plate XXIII, Figures 4-6; Plate XXIV, Figure 2 

urus similis Knowlton, U. S. Geol. Survey Twentieth Ann. 

Rept., pt. 3, p. 48, pl. 5, figs. 1-4, 1900. 

Chaney, Chicago Univ. Walker Mus. Contr., vol. 2, No. 

5, p. 173, 1920. 

This species was described from specimens collected 

Comstock, Douglas County, Oreg.', in beds interdded with lavas on the west side of the Cascade 

1nge and was also noted by Chaney in the Eagle 

·eek formation at several localities in Multnomah 

>unty, Oreg. The two specimens here figured do 

·t appear to differ essentil:!lly. 

Occurrence: Latah formation, cut along SpokPne, 

>rtland & Seattle Railway and Deep Creek half a 

ile above mouth, Spokane, Wash., collected by 

anry Fair and C. E. Fernquist, 1922; cut on Chicago, 

ilwaukee & St. Paul Railway, Spokane; collected 

r R. W. Chaney, 1922; specimen in University of 

l.lifornia Museum, -l-Im· 

Laurus princeps Heer 

Plate XXIII, Figures 1-3 

~urus princeps Heer. Lesquereux, U. S. Geol. Survey Terr. 

Rept., vol. 8 (Cretaceous and Tertiary floras), p. 2.50, 

pl. 58, fig. 2, 1883. 

Except for the fact that the Spokane leaves are a 

;tle narrower they do not differ from the leaf from 

.e auriferous gravels of Corral Hollow, Alameda 

e>unty, Calif., figured by Lesquereux. Whether or 

>t the American leaves are identical with European 

aves is a matter that need not be discussed here. 

Another very perfectly preserved example is still 

trrower but does not otherwise differ essentially. 

Occurrence: Latah formation, cut along Spokane, 

:>rtland & Seattle Railway, Spokane, Wash., collected 

r Henry Fair and C. E. Fernquist, 1922; well at 

[ica, southeast of Spokane, collected by Thomas 

arge for J. T. Pardee, August, 1922. 

Laurus californica Lesquereux 

wrus californica Lesquereux, U. S. Geol. Survey Ter~., vol. 8 I 

(Cretaceous and Tertiary floras), p. 252, pl. 57, fig. 3; I 

pl. 58, figs·. 6-8, 1883. 

Occurrence: Latah formation, cut along Spokane, 

ortland & Seattle Railway, Spokane, Wash., colcted by Henry Fair and C. E. Fernquist, 1922. 

Laurus grandis Lesquereux 

Plate XXIV, Figure 1 

:turus grandis Lesquereux, U. S. · Geol. Survey Terr. Rept., I 

vol. 8 (Cretaceous and Tertiary floras), p. 251, pl. 58, 

figs 1, 3, 1883. 

The specimen here figured appears to approach most 

osely Laurus grandis as figured by Lesquereux. It 

not so broad as the larger of Lesquereux's two 

types but is close to the smaller one. It may be only 

a very. broad leaf of Laurus princeps Heer as identified 

by Lesquereux 42 and as also identified from this 

collection, but as it is so much larger and has the 

I 

secondaries fewer and ascending for long distances it 

seems nearer L. grandis. 

I Occurrence: Latah formation, cut along Spokane, 

1 .Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922; cut 

1 1 mile west of Shelley Lake, 10 miles east of Spokane, 

collected by Henry Fair, 1922. . 

Order RANALES 

Family MAGNOLIACEAE 

Magnolia dayana Cockerell 

Plate XXIV, Figure 3 

Magnolia dayana Cockerell, Am. Naturalist, vol. 44, p. 35, 

1910. 

Magnolia lanceolata Lesquereux, Harvard Univ. Mus. Comp. 

Zoology Mem., vol. 6, p. 24, pl. 4, fig. 4, 1878. 

The Spokane material includes a single magnolia 

leaf-the one here figured-that is almost an exact 

duplicate of the original figure given by Lesquereux of 

a leaf from the ~uriferous gravels at Chalk Bluff, 

Nevada County, Calif. The California leaf was 

named Magnolia lanceolata by Lesquereux, but this 

name was found to be preoccupied, and it was re..J 

named M. dayana by Cockerell. The Spokane leaf is 

nearly perfect, lacking only the apical portion. It 

must have been about 17 or 18 centimeters long when 

perfect and is 6 centimeters wide. The type is about 

21 centimeters long and 6 centimeters wide. The 

nervation of the Spokane leaf agrees perfectly with that 

of the type, and thereean be no doubt of their identity. 

As Lesquereux pointed out, this species agrees closely, 

except for its slightly smaller size, with the living 

Magnolia acuminata Linne, the well-known cucumber 

tree of eastern North America. 

Occurrence: Latah formation, Spokane, Was4., collected by T. A. Bonser. 

Magnolia sp. 

Plate XXVII, Figure 1 

In one of the collections procured in 1923 within the 

city limits of Spokane there are a number of more or 

lessfragmentary large leaves that appear to belong. to 

'Magnolia. One of the best preserved of these, here 

figured, lacks the apical portion and most of one side. 

It appears to have been nearly elliptical, probably at 

least 15 centimeters in length and about 6 centimeters 

in width. The petiole is preserved for a length of 

nearly 2 centimeters, but it was presumably somewhat longer. Th,e midrib is extremely strong. The 

secondaries are numerous, u dozen pairs or more, thin, 

4Z Lesquereux, Leo, U. S. Geol. Survey Terr. Rapt., vol. 8 (Cretaceous and Tertiary floras), p. 250, pl. 58, ftg. 3, 1883. 
42 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

irregular, and at various angles, those near the base 

being nearly at a right angle, increasing above to an 

angle of approximately 45 °; they are camptodrome, 

arching just inside the margin. Except for an occasional 

nerville the finer nervation is not preserved. 

This leaf has the appearance of having been thick 

and coriaceous, in this respect resembling the living 

Magnolia foetida Sargent (Magnolia grandifiora of 

authors), the well-known evergreen magnolia of the · 

Middle Atlantic and Gulf States, with which it also 

agrees in size and shape, in the thick midrib, and 

in other features. It is of course presumptuous to 

assume that this was an evergreen species, perhaps the 

forerunner of Magnolia foetida, but it certainly most 

resembles that species. 

There is another less perfect leaf in the collection 

that seems to have been more nearly obovate-elliptical 

and has the secondaries more widely spaced in the 

upper portion. It is too fragmentary to figure. 

Of the several species of Magnolia that have been 

reported from deposits associated with the Columbia 

River lavas this is most like what has been identified 

as Magnolia inglefieldi Heer, 43 as found in the Mascall 

formation, 44 but it appears to differ in its more elliptical 

outline and in the thicker midrib and more numerous · 

secondaries, though a larger series might show less 

difference. 

The specimens available are so fragmentary that it 

has seemed best not to give a specific name until more 

and better material is available. . 

Occurrence: Latah formation, Twelfth Avenue and 

Thor Street, Spokane, Wash .. collected by Henry Fair 

and Kirk Bryan, 19~3. 

Order ROSALES 

Family HAMAMELIDACEAE 

Liquidarnbar pachypbyllurn Knowlton 

Plate XXII, Figure 7; Plate XXIX, Figure 1 

Liquidg,mbar pachyphyllum Knowlton, U. S. Geol. Survey Bull. 

204, p. 63, pl. 9, fig. 1, 1902. 

Chaney, Chicago Univ. Walker Mus. Contr., vol. 2, No. 5, 

p. 17 4, pl. 15, figs. 2, 3, 1920. · 

Several more or less fragmentary leaves of Liq_uidambar are included in the Spokane material and are 

believed to be identical with Liq_uidambar pachyphyllum 

Knowlton; from the Mascall formation of the John 

Day Basin, Oreg. The example here figured is a 

little larger than any heretofore referred to this species, 

but it does not differ otherwise in essential particulars. 

The average size before reported is from 6.5 to 7.5 

centimeters long and 7 centimeters broad, whereas the 

specimen here figured must have been nearly 10 centimeters broad and probably about 8 or 9 centimete~ 

long. A thick carbonaceous film represent~ the thick 

· substance of the leaf in the type specimen as described. 

43 Heer, Oswald, Flora fossils arctica, vol. 1, pl. 15, figs. 4, 5; pl. 18, figs. 1-3, 1868. 

H Knowlton, F. H., U. S. Geol. Survey Bull. 204, p. 58, 1902. 

Where this substance has crumbled away along the 

margins of the lobes it has obscured · the teeth, but 

where well preserved the teeth can be seen as in the 

type. 

Liq_uidambar pachyphyllum was found by Chaney 45 

at a number of localities in the Eagle Creek formation 

of Multnomah County, Oreg. An additional wellpreserved specimen was found by Messrs. Fair and 

Bryan in 1923. This specimen (Pl. XXII, fig. 7) is 

indistinguishable from the smaller of the two leaves 

figured by Chaney. In the same beds with this leaf 

is the finely preserved fruit (Pl. X, fig. 10) that is 

probably the fruit of this species, though there is no 

possibility of connecting them organically. 

Occurrence: Latah formation, well near Mica, 

southeast of Spokane, Wash., collected by Thomas 

Large for J .. T. Pardee, August, 1922; cut No. 2 on 

Oregon-Washington Railroad & Navigation Co.'s line, 

Spokane, Wash., collected by Henry Fair and Kirk 

_Bryan, May, 1923. 

Liquidambar, fruit 

Plate X, Figure 10 

This fruit was found in the same beds as the speci'es 

last discussed and in all reasonable probability belongs 

to it, but as they are not organically connected they 

are perhaps best kept separated. This head is very 

perfectly preserved and shows many of the individual 

fruits around the outer margin. These are somewhat 

shorter and not so pointed as in the living species 

(Liq_uidambar styracifiua Linne). 

Occurrence: Latah formation, cut No.2 on OregonWashington Railroad & Navigation Co.'s line, Spokane, Wash , collected by Henry Fair and Kirk Bryan, 

May, 1923. 

Family SAXIFRAGACEAE 

Hydrangea bendirei (Ward) Knowlton 

Plate XXIV, Figure 6 

Hydrangea bendirei (Ward) Knowlton, in Merriam, . California 

1.Jniv. Dept. Geology Bull., vol. 2, No. 9, p. 309, 1901. 

Knowlton, U. S. Geol. Survey Bull. 204, p. 60, pl. 9, 

figs. 6, 7, 1902. 

Marsilea bendirei Ward, U. S. Geol. Survey Fifth Ann. Rept., 

p. 446, 1885. 

Porana bendirei (Ward) Lesquereux, ~ U. S. Nat. Mus. Proc., 

vol. 11, p. 16, pl. 8, fig. 4, 1888. 

The example figured is the only one thus far observed. It is absolutely indistinguishable from the 

type specimens and has not before been found except 

at the type locality. 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected for and donated by the Spokane Public Museum. 

'~Chaney, R. W., Chicago Univ. Walker Mus. Contr., vol. 2, No.5, p. 174, 

pl. 15, figs. 2, 3, 1920. 
FLORA OF THE L TAH FORMATION 43 

Family DRUP ACEAE 

Prunus rustii Knowlton, n. sp. 

Plate XXIV, Figures 4, 5 

Leaves small, evidently rather thin and membrana-

)Us, lanceolate or slightly ovate-lanceolate, rounded · 

d obtusely wedge-shaped at the base; apex missing 

t probably acuminate. The margin is finely and 

[Lrply serrate, with a slight tendency for the teeth 

tered by the secondaries to project beyond the line 

the others, the teeth apparently glandular-tipped. 

1e petiole is long and slender, nearly 1.5 centimeters 

1g, and the midrib rather thin and straight. There 

e probably eight or ten pairs of thin, opposite or 

bopposite secondaries that stand at an angle of 

·out 45°, regularly spaced and craspedodrome, many 

them with three or four short tertiary branches 

1ich pass to marginal ·teeth; nervilles numerous, 

1th broken ~nd percurrent; finer nervation producg a fine, irregularly quadrangular network. 

This species is represented by two specimens, both 

which are figured. The smaller specimen (fig. 4), 

)ill Coeur d'Alene, lacks the apex and most of one 

ie. It was probably about 4.5 centimeters long and 

25 centimeters wide. The other example (fig. 5), 

)ill Spokane, lacks only the apical portion, the reainder being exceptionally well preserved. It was 

·obably 6 centimeters or more in length and is 2.5 

ntimeters wide. This leaf has the secondaries at a 

[ghtly more acute angle than the smaller leaf, but 

.herwise there is no essential difference. 

Among living species Prunus rustii suggests Prunus 

Lgustifolia Marshall, of the Atlantic and Gulf States 

om Delaware southward, except that there is no 

ridence of glands at the top of the petiole. Among 

ssil species from this region it is perhaps closest to 

runus? tuffacea Knowlton,46 from the Mascall formaon, but in that species the secondaries are more 

1merous and at a lower angle of divergence. and not 

1 the secondaries end in marginal teeth. 

I take pleasure in naming this species in honor of 

[r. H. J. Rust, who collected one of the types. 

Occurrence: Latah formation, Edwards ranch, 

tanley Hill, Coeur d'Alene, Idaho, collected by H. J. 

.ust, July, 1920; cut No.2 on Chicago, Milwaukee & 

t. Paul Railway, Wash., collected by Henry Fair and 

irk Bryan, 1923. 

Family CAESALPINIACEAE 

Cercis? spokanensis Knowlton, n. ~p. 

Plate XXIX, Figure 9 

Pod linear or linear-oblong, flat, with a short stalk, 

b.e valves apparently thin, thickened along the upper 

uture, reticulate-veined, apparently with several 

eeds: 

t6 Knowlton, F. H., U.S. Geol. Survey Bull. 204, pl. 11, figs. 2, 3, 6, 7, 1902. 

This little pod is now about 3.5 centimeters long 

(including the I stalk, which is 4 millimeters in length) 

and 1.5 centim!eters wide. The valve, as may be seen 

from the drawing, is finely reticulate-nerved, and there 

is a faint indication of the presence of three large 

round seeds. 

Although the apparent affinity of this species is 

with the living Cerci~ canadensis Liml.e, it has seemed 

best to question the generic reference, for the identification is more or less uncertain. 

Occurrence: Latah formation, Deep Creek half a 

mile above mouth, northwest of Spokane, Wash., 

collected by Henry Fair and C. E. Fernquist, 1922. 

Family PAPILIONACEAE 

Sophora alexanderi Knowlton, n. sp. 

Plate XXVIII, Figures 3-5 

Leaflets thin, elliptical or slightly ovate-elliptical, 

2.5 to 3.25 centimeters long, 12 to 16 millimeters wide, 

broadest near or · just below the middle, abruptly 

rounded or even slightly heart-shaped at the base, 

obtuse, with a distinct tendency to be slightly emarginate, at the apex·; margins entire; petiole short, stout; 

midrib relatively very strong; secondaries about eight 

or nine pairs, at somewhat irregular distances, considerably curved upward, strongly camptodrome, 

arching well below the margin and each passing to the 

secondary next· above; finer nervation producing a 

rather large, irregularly quadrangular network. 

There is consid~rable variation in the size and shape 

of the three examples referred to this species, but as 

they come from the same locality and have certain 

characters in common it is assumed that they are only 

variants of a single species. Thus, the leaf shown in 

Figure 4 is relatively long, truncate at the base, and 

minutely em~rginate at the apex. That shown in 

Figure 5 is slightly heart-shaped at the base and also 

minutely emarginate. The one shown in Figures 3 

and 3a is shorter, relatively broader, rounded at the 

base, and distinctly emarginate at the apex. The 

thick midrib and irregularly spaced camptodrome 

secondaries are the same in all. 

Little leaves or leaflets of this type are difficult to 

place satisfactorily, yet these appear to agree well with 

others that have been referred to Sophora. For example, the present species is very similar to Sophora wilcoxiana Berry,4 from beds of Wilcox age in the 

Lagrange formation of Tennessee, though there are 

minor differences in the nervation. 

I take pleasure ,in naming this little species in honor 

of Mr. A. C. Alexander, of Spokane, who has done 

much to develop the mineral resources of the region 

and who has been especially interested in finding and 

collecting fossil plants. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. ' 

• Berry, E. W., U. S. Geol. Survey Prof. Paper 91, p. 241, pl. 47, figs. 1-lS, 1916. 
44 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 . I . 

Sophora spokanensis Knowlton, n. sp. 

Plate XXVIII, Figure 6 

To found a species on this little fragment is perhaps 

Unwise, but it appears to differ from anything else 

from these beds and can probably be recognized if 

again found. It is elliptical-lanceolate, with a rounded 

and obtuse apex and probably a somewhat similarly 

rounded base. The length was probably not far from 

4 centimeters and the width a little over 1 centimeter. 

The nervation consists of a relatively very thick midrib and numerous alternate thin camptodrome secondaries at a low angle of emergence. The finer nervation can not be made out with certainty. 

This little leaflet is the only one found. It differs 

from the preceding species, Sophora alexanderi, in being 

relatively longer and narrower and in the more numerous, lower-angled secondaries. It is very similar to 

certain of the intermediate-sized leaflets of Sophora 

wilcoxiana Berry/8 from beds of Wilcox· age in the 

Lagrange formation of Tennessee-in , fact, it is difficult to note characters for their separation. 

Occurrence: Latah formation, Deep Creek, northwest of Spokane, Wash., collected by IIenry Fair and 

Kirk Bryan, June 3, 1923. 

Robinia? sp. 

Plate XXVIII, Figures 7, 7a 

Leaflet thin, elliptical-ovate, 15 millimeters long, 9 

millimeters wide, rounded and truncate or almost 

heart-shaped at the base, obtuse at the apex; petiolule 

very short, slightly over 1 millimeter; nervation light, 

consisting of a straight midrib and about seven pairs 

of thin camptodrome secondaries at an angle of ab,out 

50°; finer nervation not discernible. 

Isolated leaflets of this character are so small and 

generally nondescript that it is almost impossible to 

place them satisfactorily. The most that can be said 

in the present instance is that it resembles the leaflets 

of certain living species of Robinia, such for example 

as R. ·pseudacacia Linne, of eastern North America, 

but it is difficult to establish identity. It will at least 

call attention to the presence of this type of plant, but 

the future will have to settle its identity; 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Henry Fair and C. E. Fernquist, 1922. 

Genus MEIBOMITES Knowlton, n~ gen. 

Characters of the species. 

Meibomites lucens Knowlton, n. sp. 

Plate XXVIII, Figure 10 

This appears to be of the type of the lateral leaflet 

in many living species of Meibomia. It was clearly 

thin. It is very broadly .ovate, · being · abruptly 

48 Berry, E. W ., U . S. Geol. Survey Prof. Paper 91, p. 241, pl. 47, figs. 1-13, 1916. 

rounded below to the nearly truncate base and above 

to a slender acute tip. The margin is perfectly entire, 

and the petiolule if ever present is not now preserved. 

The nervation is very thin and delicate, consisting of 

a slender, straight midrib and eight or nine pairs of 

· camptodrome secondaries. The lowest pair arise at 

the extreme base of the blade at an angle of approxi-:-

mately 45°; the others are at irregular distances and 

at an angle of 30° or 40°; all are curved upward, and 

each joins the one next above, far inside the margin. 

Between these loops and the margin is a series of large 

and small loops. The nervilles are not very numerous 

and are very thin, mainly percurrent. The finer 

nervation produces very irregular areas. 

The genus Meibomia comprises about 160 species, 

natives of warm and temperate North and South 

America, South Africa, and Australia. They are 

perennial herbs, often woody at the base, mainly with 

trifoliolate leaves. The terminal leaflet is shortpetioled, but the lateral ones are almost always cl,osely 

sessile. The fruit consists of a flat loment of several 

coriaceous jointed indehiscent segments. No part of 

the plant has apparently been found in a fossil state. 

The present specimen appears to me to be a sessile 

lateral leaflet very similar at least to those of a number 

of living species, such as Meibomia arenicola Vail and 

M. ochrole1.tca (Curtis) Kuntze, but as those species 

seem to have a more regularly pinnate nervation it 

seems best not to refer the Spokane form to the living 

genus direct, hence I have erected the new genus 

Meibomites for it. _ 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected 

by Henry Fair and C. E. Fernquist, 1922. 

Order SAPINDALES 

Family CELASTRACEAE 

Celastrus fernquisti Knowlton, n. sp. 

Plate XXVIII, Figure 2 

Leaf evidently thin, elliptical or elliptical-ovate, 

abo{tt 7 centimeters long and 5 centimeters w:ide, 

broadest about the middle, rather abruptly rounded 

to the truncate, slightly heart-shaped ,base and apparently to a moderately pointed apex; margin entire 

at base thence serrate, the teeth somewhat irregular, 

sharp; ~idrib strong, particularly below; secondari~s about seven pairs, subopposite, all but the lowest pair 

at an angle of about 40°, slightly curved upward, 

craspedodrome, those in the middle of the blade with 

several tertiary branches which also terminate in the 

teeth; nervilles numerous, thin, often broken. 

This species is represen.ted by the half of a leaf as 

figured, which shows the base very well but lacks the 

extreme tip. The petiole is not retained. The mar~ 

ginal teeth and the nervation . are well shown in the 

figure. 
FLORA OF THi LATAH FORMATION 45 

This species seems undoubtedly congeneric with r. It has been suggested that these leaves figured by 

number of species from the Fort Union formati; Lesquereux, especially the larger ones, are n10re 

described by Ward 49 as Oelastrus. These forms we e properly referable to Platanus than to Acer. Be that 

abu~dant in the. Fort. Union format~on, and one of t. e a~ i~ may, the present leaf certainly agrees with the 

species ( 0. taunnensts) was recogmzed by Berry 50 If spemmen quoted above. 

the Wilcox formation of Louisiana. The leaf und~r Occurrence: Latah formation, well at Mica, southconsideration agrees very well with some of the Fort east of Spokane, Wash., collected by Thomas Large 

Union forms, especially 0. taurinensis, but differs in for J. T. Pardee, August, 1922. 

having fewer secondaries, which are not so much 

curved upward. 

In his original discussion of 0. taurinensis Ward 

debated whether or not it might better be referred to 

Grewiopsis or Pterospermites, and Berry states that 

if it had to be described anew he would be inclined to 

place it in Gre·u"iopsis, but, be this as it may, the present 

form seems near enough to be considered congenenic 

with it, and thus it is left until a revision and full 

consideration of the Fort Union flora is made. 

I take pleasure in naming this species in honor of 

Mr. C. E. Fernquist, of Spokane, who collected it. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway west of Latah Creek, 

Spokane, Wash., collected by Henry Fair and C. E. 

Fernquist, 1922. 

Family ANACARDIACEAE 

Rhus typhinoides Lesquereux 

Plate XXVII, Figure 5 

Rhus typhinoides I1esquereux, Harvard Univ. Mus. Comp 

Zoology Mem., vol. 6, No. 2, p. 29, pl. 9, figs. 1-6, 1878. 

The single specimen figured appears to belong to 

this species. It lacks the upper half, but in size, 

inequilateral base, marginal teeth, and nervation it 

agrees well with Lesquereux's figures, except that the 

secondaries are not so numerous in the basal portion. 

Occurrence: Latah formation, north side of clay 

pit 2 miles south of Vera, Wash., collected by Henry 

Fair, June 29, 1923. 

Family STAPHYLEACEAE 

Acer bendirei Lesquereux 

Plate XXVII, Figure 3 

Acer bendirei Lesquereux, U. S. 1\at. Mus. Proc., vol. 11, p. 14, 

pl. 5, fig .. 5, 1888. 

AI though the specimen here figured is rather fragmentary, enough of it is retained to show clearly that 

it is indistinguishable from the leaf figured byLesque:... 

reux, as noted above. In the same paper Lesquereux 

figured several other much larger leaves, and in a still 

earlier paper 51 specimens even larger were figured 

under the name Acer trilobatum productum Heer. 

They are all from the Mascall formation of the John 

Day Basin, Oreg. 

•g Ward, L. F., U.S. Geol. Survey Sixth Ann. Rept., p. 555, pl. 52, 1886; U.S. 

Geol. Survey Bull. 37, p. 79, 1887. I 

so Berry, E. W., U.S. Geol. Survey Prof. Paper 91, p. 267, pl. 60, figs. 1-3, 1916. 51 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous and Tertiary 

florns), p. 253, pl. 59, figs. 1, 2, 4, 1883. 

/ 

Acer merriami Knowlton 

Plate XXVIII, Figure 1 

Acer merriami Knowlton, U. S. Geol. Survey Bull. 204, p. 74, 

pl. 14, fig. 7, 1902. 

Hardly more than the basal portion of this leaf, 

with the petiole complete, is preserved, but as it 

agrees with the type leaf of Acer merriami, it is so 

identified. 

Occurrence: Latah formation, well at Mica, southeast of Spokane, Wash., collected by Thomas Large 

for J. T. Pardee, August, 1922. 

Acer minor Knowlton-! 

Plate XXVII, Figure 4 

Acer minor Knowlton, U. S. Geol. Survey Bull. 204, p. 76, pl. 

14, figs. 2, 3, 1902. 

Although it may be more or less hazardous to 

identify species of. maple from fruits, the present 

identification seems fairly certain. Three species 

based largely on size of fruits were characterized 

from the Mascall formation of the John Day Basin, 

and as no intermediate sizes were noted it was assumed 

that the species were valid, each perhaps corresponding to one of the three species characterized from the 

leaves. 

Maples do not seem to have been as abundant in 

the Spokane area as they were in the John Day Basin, 

the fruit figured being the only one that has come to 

my attention. 

This species is similar to Acer aq_uilum Chaney,52 

from the Eagle Creek formation of the Columbia 

River region, but is considerably narrower. 

Occurrence: Latah formation, Deep Creek, northwest of Spokane, Wash., collected by Henry Fair 

and Kirk Bryan, June 24, 1923. 

Acer chaneyi Knowlton, n. sp. 

Plate XXVII, Figure 2 

Leaf rather thin, rudely triangular, truncate at the 

base, very deeply three-lobe4, the basal lobes lanceolate, sharp-pointed, with a small basal lobe and in the 

middle a larger few-toothed lobe on either side, the 

upper part sharply toothed; middle lobe with a pair 

of opposite toothed lobes high above the sinus and 

probably a toothed margin still above this (apex 

destroyed); sinuses very deep, rather sharp; nervation 

~3 Chaney, R. W., Chicago Univ. Walker Mus. Oontr., vol. 2, No. 5, p. 178, pl. 

18, fig. 2, 1920. 
FLORA OF THE LATAH FORMATION 45 

This species seems undoubtedly congeneric with a 

number of species from the Fo~t Union formation · 

described by Ward 49 as Oelastrus. These forms were 

abundant in the Fort Union formation, and one of the 

species ( 0. taurinensi.s) was recognized by Berry 50 in 

the Wilcox formation of Louisiana. The leaf under 

consideration agrees very well with some of the Fort 

Union forms, especially 0. taurinensis, but differs in 

having fewer secondaries, which are not so much 

curved upward. 

In his original discussion of 0. taurinensis Ward 

debated whether or not it might better be referred to 

Grewiopsis or Pterospermites, and Berry states that 

if it had to be described anew he would be inclined to 

place it in Gre·u''iopsis, but, be this as it may, the present 

form seems near enough to be considered congeneric 

with it, and thus it is left until a revision and full 

consideration of the Fort Union flora is made. 

I take pleasure in naming this species in honor of 

Mr. C. E. Fernquist, of Spokane, who collected it. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway west of Latah Creek, 

Spokane, Wash., collected by Henry Fair and C. E. 

Fernquist, 1922. 

Family ANACARDIACEAE 

Rhus typhinoides Lesquereux 

Plate XXVII, Figure 5 

Rhus typhinoides Lesquereux, Harvard Univ. Mus. Comp 

Zoology Mem., vol. 6, No.2, p. 29, pl. 9, figs. 1-6, 1878. 

The single specimen figured appears to belong to 

this species. It lacks the upper half, but in size, 

inequilateral base, marginal teeth, and nervation it 

agrees well with Lesquereux's figures, except that the 

secondaries are not so numerous in the basal portion. 

Occurrence: Latah formation, north side of clay 

pit 2 !miles south of Vera, Wash., collected by Henry 

Fair, June 29, 1923. 

I Family STAPHYLEACEAE 

Acer bendirei Lesquereux 

Plate XXVII, Figure 3 

Acer bendirei Lesquereux, U. S. JSat. Mus. Proc., vol. 11, p. 14, 

pl. 5, fig .. 5, 1888. 

Although the . specimen here figured is rather fragmentary, enough of it is retained to show clearly that 

it is indistinguishable from the leaf figured by Lesquereux, as noted above. In the same paper Lesquereux 

figured several other much larger leaves, and in a still 

earlier paper 51 specimens even larger were figured 

unde~ the name Acer trilobatum productum Heer. 

They are all from the Mascall formation of the John 

Day Basin, Oreg. 

4g Ward, L. F., U. S. Geol. Survey Sixth Ann. Rept., p. 555, pl. 52, 1886; U.s. 

Geol. Survey Bull. 37, p . 79, 1887. 

5° Berry, E . W., U.S. Geol. Survey Prof. Paper 91, p. 267, pl. 60, figs.1-3, 1916. 51 Lesquereux, Leo, U.S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous and Tertiary 

tloms), l253, pl. 59, figs. 1, 2, 4, 1883. 

85658°-26--4 

/ 

It has been suggested that these leaves figured by 

Lesquereux, especially the larger ones, are more 

properly referable to Platanus than to Acer. Be that 

as it may, the present leaf certainly agrees with the 

specimen quoted above. 

Occurrence: Latah formation, well at Mica, southeast of Spokane, Wash., collected by Thomas Large 

for J. T. Pardee, August, 1922. 

Acer merriami Knowlton 

Plate XXVIII,' Figure 1 

Acer merriami Knowlton, U. S. Geol. Survey Bull. 204, p. 74, 

pl. 14, fig. 7, 1902. 

Hardly more than the basal portion of this leaf, 

with the petiole complete, is preserved, but as it 

agrees with the type leaf of Acer merriami, it is so 

identified. 

Occurrence: Latah formation, well at Mica, southeast of Spokane, Wash., collected by Thomas Large 

for J. T. Pardee, August, 1922. 

Acer minor Knowlton -! 

Plate XXVII, Figure 4 

Acer minor Knowlton, U. S. Geol. Survey Bull. 204, p. 76, pl. 

14, figs. 2, 3, 1902. 

Although it may be more or less hazardous to 

identify species of. maple from fruits, the present 

identification seems fairly certain. Three species 

based largely on size bf fruits were characterized 

from the Mascall formarion of the John Day Basin, 

and as no intermediate si~es were noted it was assumed 

that the species were valid, each perhaps corresponding to one of the three t. 

1 

eci. es characterized f. rom the 

leaves. · 

Maples do not seem 10 have been as abundant in 

the Spokane area as the were in the John Day Basin, 

the fruit figured being the only one that has come to 

my attention. I 

This species is simila~ to Acer ag_uilum. Chaney,53 

from the Eagle Creek formation of the Columbia 

River region, but is cons· derably narrower. 

Occurrence: Latah fo~ation, Deep Creek, northwest of Spokane, W h., collected by Henry Fair 

and Kirk Bryan, June 2t , 1923. 

Acer chane1 Knowlton, n. sp. 

Plate X! VII, Figure 2 . 

Leaf rather thin, rud~y triangular, truncate at the 

base, very deeply three obeq, the basal lobes lanceolate, sharp-pointed, wit a small basal lobe and in the 

middle a larger few-too hed lobe on either side, the 

upper part sharply toothed; middle lobe with a pair 

of opposite toothed lob s high above the sinus and 

probably a toothed margin still above this (apex 

destroyed); sinuses very deep, rather sharp; nervation 

6~ Chaney, R. W., Chicago Univ. Walker Mus. Contr., vol. 2, No.5, p. 178, pl. 

18, fig. 2, 1920. 
46 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

relatively strong, three-ribbed from the very base of 

the blade; midrib with a slender nerve passing up to 

and forking around the sinus, with about three pairs 

of camptodrome secondaries below the first pair of 

lobes, then a strong pair that end in the apex of J:,he 

lobes, and above these probably other camptodrome 

secondaries; lateral ribs nearly as strong as the midrib, at an angle of about 45°, with both camptodroflle 

and craspedodrome secondaries; nervilles slender, 

forming an irregular network. 

~ This very characteristic species is represented by 

the single example here figured, which is nearly perfect except for the upper portion of the middle lobe. 

The length was probably 8 or 9 centimeters and the 

width between the lateral lobes about 8 centimeters. 

The lateral lobes are about 5 centimeters long and 1 

centimeter wide at the base. The width of the 

middle lobe just above the sinuses is slightly less than 

1 centimeter. The petiole is not preserved. 

This species does not appear to approach very 

closely any living American species, nor is it like any 

fossil species thus far described from the region. It 

is, however, similar in many respects to Acer angustilobum, 53 from the Swiss Miocene. This European 

species is of about the same size as ours and is threelobed and cut deeply by the sinuses, but it differs in 

having all the lobes evenly and sharply toothed. 

I take pleasure in naming this species in honor of 

Dr. Ralph W. Chaney, who collected ik 

Occurrence: Latah formation, Spokane, Wash., 

collected by R. W. Chaney, ·July, 1921. Type in 

the University of California, No. NM· 

Order ERICALES 

Family V ACCINIACEAE 

Vaccinium salicoides Knowlton, n. sp. 

Plate XXVIII, Figures 9, 9a 

Leaf small (about 2 centimeters long, 6 millimeters 

wide), very thick, linear-lanceolate, broadest at 

about the middle, wedge-shaped at the base and 

rather obtuse at the apex; margin perfectly entire; 

midrib very thick, especially where it passes into 

the petiole; secondaries five or six pairs, thin, curving 

upward for long distances, camptodrome, each joining the one next above by several loops; finer nervation producing a regular, deeply impressed quadrangular network. 

With only a single small rather nondescript leaf 

for comparison it is difficult to place this form with 

certainty. It is not unlike leaves of the living Vaccinium pennsylvanicum Lamarck, though apparently 

somewhat thicker. It also resembles certain species 

of Salix but is thicker than is usual in willow leaves. 

Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

63 Heer, Oswald, Flora tertiaria Helvetiae, vol. 3, pl. 118, fig. 7, 1859. 

Order EBEN ALES 

Family EBENACEAE 

Diospyros andersonae Knowlton, n. sp. 

Plate XXVII, Figure 6 

This species, based on the splendid calyx figured, 

is so close to the living persimmon (Diospyros virginiana Linne) that separation is hardly possible, 

but it is so far outside the present range of this Jiving 

species that its persistence since the Miocene seems 

improbable. The fossil form, however, is somewhat 

smaller than the usual-sized calyx in Diospyros 

virginiana and has the lobes relatively broader and 

shorter, but at most the differences are not great. 

It has a spread over all of 3 centimeters, and the 

greatest width of the lobes is 11 or 12 millimeters. 

The length of the lobes is about the same as their 

width. This calyx is preserved right side up, so to 

speak, and was evidently mature when fossilized, 

for the central depression or" cup" in which the berry 

rested is pronounced. In the living species the berry 

adheres to the calyx with great tenacity until maturity, 

when it readily separates. 

Diospyros virginiana, the well-known persimmon, is . 

very common in the South Atlantic and Gulf States, 

ranging from Connecticut west to Iowa and thence 

south through eastern Kansas to Arkansas and 

Louisiana. It is not known west of the Mississippi 

basin. It is evident that the type almost in its present 

form was in existence in middle Miocene time and at 

least a thousand miles west of its present western 

limit. 

The Spokane persimmon is named in honor of Miss 

Alice Anderson, who collected it. 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Alice Anderson for the Spokane Museum, 

from which the specimen is contributed. 

Diospyros? microcalyx Knowlton, n. sp. 

Plate XXII, Figures 5, 6 

This species is represented by the two examples 

figured. They clearly represent a dry, leathery ealyx 

from which the berry or fruit of some kind has fallen. 

They are regularly five-lobed, the individual lobes being 

obovate or oblong and very obtuse and rounded at 

the apex and cut within a short distance of the central 

disk. The nervation of the lobes is obscure but 

apparently consists of fine veins that run through the 

whole length. The central disk or point of attachment for the berry is over 1 millimeter in diameter 

and shows faint outlines of five vascular bundles. 

The width between the tips of the lobes is 8 or 9 

millimeters. 

I am less certain about the correctness of this 

generic reference than for the species last described, 

but it seems to approach most closely the calyx of the 
FLORA OF THE LATAH FORMA!TION 47 

black persimmon (Diospyros texana heele, Brayo- PLANTk OF UNCERTAIN SYSTEMATIC POSITION 

dendron texanum (Scheele) Small) of Texas and Nuevo PJyllites amplexicaulis Knowlton, n. sp. 

Leon, Mexico. It is, however, very much smaller and J 

has the lobes relatively broader and more obtuse than Plate XXIX, Figure 3 

in this living species. This is very peculiar organism, the exact nature 

T~ese ·spokane specimens also resemble certain of which ~as not yet been interpreted. It consists 

species of Porana from the lake beds at Florissant, of a stout stem, of which 7.5 centimeters in length is 

Colo., such_ as Porana_ cockerelli Knowlton,S4 although preserved, lon which are at irregular intervals (2 to 

the latter IS many times larger and has the ovoid 3 centime ers) pairs of small opposite, sessile, flat 

capsule preserved in the center. The lobes of the expanded i rgans. These are approximately circular, 

calyx in Porana cockerelli have only about three strong from 7 to 10 millimeters in width or diameter, and 

nerves running from the base to the apex, whereas in with the 1rgin cut into regular strong deltoid teeth. 

the specimens under consideration· there are a great From the center or point of attachment there are 

number of fine veins or wrinkles that simulate veins. some eight or nine strong, straight rib~, which enter 

Another species of Porana (P. similis Knowlton), also the teeth. No finer nervation can be detected. These 

from Florissant, is similar to P. cockerelli but has the organs see to be coriaceous and to be stipular rather 

calyx lobes pointed instead of obtuse. This also has than stric ly foliar in function. At .the points of 

the capsule preserved. attachmenr

1 the stem is constricted or disorganized, 

Altogether the Spokane specimens seem more like as if there ad been other organs that have now disDiospyros than Porana, but considering the uncer- appeared. 

tainty it has appeared best to question the generic I am. no able to suggest any affinity for this organreference. ism. I 

Occurrence: Latah for_mation, deep cut on Spokane, Occurre11-ce: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., col- Portland ~ Seattle Railway, Spokane, Wash., collected for and contributed by the Spokane Public lected by enry Fair and C. E. Fernquist, 1922. 

Museum. 

Order MALVALES 

Family MALVACEAE 

Malva? hesperia Knowlton, n. sp. 

Plate XXIX, Figure 11 

Fruit depressed globose, about 1 centimeter in 

diameter, made up of a ring of about 20 indehiscent, 

smooth carpels that are without apparent beak or 

reticulations. 

The specimen figured, the only one observed, Is 

fortunately preserved in a normal position, . so that· 

all the carpels are exposed. It is certainly malvaceous 

and seems to be generically identical with the fruits 

of species of Malva, such as Malva alcea Linne and 

M. moschata Linne, but Malva is not a native of 

North America. The genus comprises about 30 Old 

World species, five or six of which are more or less 

widely naturalized in this country. It is also like 

Althea, but this is an Old World genus of some 15 

species, only one of which (A. officinalis Linne) has 

been introduced into North America. 

There are a number of native genera with the 

fruit more or less like the Spokane specimen, such as 

OaUirrhoe, but the carpels of Oallirrhoe are beaked 

and are also more or less reticulated. Others, such as 

Malvastrum and Sida, are eliminated for similar 

reasons. 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected for and submitted by the . Spokane Public 

Museum. 

4 Knowlton, F : H., U.S. Nat. Mus. Proc., vol. 51, p. 287, pl. 27, fig. 3, 1917. 

hyllites crustacea Knowlton, · n. sp. 

Plate XXIX, Figure 6 

This lit e leaf, the only one of its kind observed 

in the co ection, is narrowly lanceolate,.. broadest 

well abovel the middle, whence it narrows below to a 

long wedgr-shaped base and above to the acutely 

pointed tip. It is about 5 centimeters long and 

1 · centime~er wide. It was evidently rather thick, 

for over Jost of the leaf the carbonaceous film still I . 

re~ains. .fhis carbonaceous matter has checke.d an_d 

wrinkled If such a manner that the nervatiOn Is 

obscured, ~nd where it has been removed the impression of the nervation is hardly discernible. If · 

correctly terpreted there appear to have been a , 

large numli>er of light, close, parallel secondaries that 

are appar,

1

ntly craspedodrome. The midrib seems 

strong for the size of the leaf. None . of the finer 

nervation can he made out. I 

This little leaf has some resemblance, in shape at 

least, to cehain narrow, entire-leaved species of Salix, 

but the ne vation is so uncertain that it is best placed 

in_ PhylliteJ. It also agrees in shape with the smaller 

of the figuJ.ed types of Laurus. salicifolia Lesquereux 55 

(now L. sdliciformis Knowlton and Cockerell), but it 

has more sr condaries and no evidence of the . very fine 

nervation (j)f that species. 

Occurrerlce: Latah formation, well at Mica, southeast of Spbkane, Wash., collected by Thomas Large 

or J. T. Pdrdee, August, 1922. 

~~ Lesquereux, Leo, U. S. Geol. Survey Terr. Rept., vol. 8 (Cretaceous and 

Tertiary floras), p. 252, pl. 58, fig. 3, 1883. 
48 SHOR.TER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

Phyllites pardeei Knowlton, n. sp. 

Plate XXIX, Figure 13 

Leaf apparently very thick, 'elliptical, abruptly 

rounded to the obtuse base and apex; margin with 

about four very low, obtuse teeth or lobes on each 

side; petiole moderately strong, about 1 centimeter 

long; midrib very strong for the size of the leaf, slightly 

irregular or bent; secondaries three pairs, all strong 

and more or less zigzag, the lower pair strongest, subopposite, arising a considerable distance above the top 

of the petiole, ending in a marginal tooth, each with a 

series of large loops on the lower side; middle pair of 

secondaries subopposite, forking and sending the 

branches to the marginal teeth; upper secondaries 

alternate, ending in the upper of the four marginal 

teeth; nervilles few, strong; finer nervation very 

strong and well marked, producing a network of large, 

irregular meshes throughout the blade. 

This leaf is well characterized by its elliptical shape, 

the four low, obtuse . teeth or lobes on each side, the 

three pairs of craspedodrome secondaries, the lowest 

of which are so far above the base of the blade, and 

above all by the peculiar large-meshed network of :finer 

veins. Nevertheless, I am not now able to suggest a 

satisfactory generic reference. The shape and the 

manner in which the lower pair of secondaries arise, 

as well as . the finer nervation, suggest the genus 

Oreodaphne, but the presence of the low marginal teeth 

or lobes i not in accord with this genus. I am there-· 

fore constrained to place it in Phyllites until it can be 

more satisfactorily allocated. 

This species has been named in honor of Mr. J. T ~ 

Pardee, of the United States Geological Survey, who 

was €specially instrumental in procuring the collections that are the basis of this report. 

Occurrence: Latah formation, cut along Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected. by Henry Fair and C. E. Fernquist, 1922. 

Phyllites peculiaris Knowlton, n. sp • . 

Plate XXIX, Figure 2 

Leaf evidently very thick, as the nervation is all 

deeply impressed; presumably elliptical, though the 

upper portion is missing; margin apparently entire; 

midrib extremely strong for the size of the leaf and 

slightly irregular. The number of pairs of secondaries 

can not be determined, though there are at least fo-ur 

oairs. The lower pair is rather thin and passes up-

~ard for only a short distance; they arise from the 

top of the petiole. The other secondaries are alternate, at an angle of about 20°, camptodrome, and curving upward for long distances, each joining the one 

above by a series of loops. There are a number of 

strong intermediate seco:p.daries and an occasional nerville, but most of the :finer nervation is obsolete. 

This leaf has some resemblance to Phyl;tites pardeei, 

but that form has three or four low marginal teeth or 

lobes, and the lower secondaries arise at a distance 

above the top of the petiole. This leaf also resembles 

in a general way certain leaves that have been referred 

to Ficus, but in the absence of more complete data I 

think best to refer it to Phyllites. It can be easily 

recognized if again found. -

Occurrence: Latah formation, Twelfth A venue and 

Thor Street, Spokane, Wash., collected by Henry Fair 

and Kirk Bryan, June, 1923. 

Phyllites sophoroides Knowlton, n. sp. 

Plate XXVI, Figure 8 

This little leaf or leaflet, as it probably is, is the 

only one of its kind observed. It was apparently 

thin and is long elliptical, being about· equally rounded 

at both ends. The base appears to be slightly unequal-sided, a:Qd the apex is abruptly apiculate. The 

midrib is fairly strong, and the secondaries are very 

thin and delicate. There are nine or ten pairs of 

rather remote secondaries that curve near the 'margin, 

and each passes in a series of bows to the one next 

above. The nervilles are numerous, very irregular, 

and with the finer nervation producing a very irregular 

delicate network. The specimen is 4. 7 5 centimeters 

long and 2.5 centimeters wide near the middle. 

This appears to be a leaflet of a leguminous plant, 

being, for instance, similar to many that have been 

referred to Sophora, but as there is only a single 

example, and this not quite perfect, it is best referred, 

at least, temporarily, to the noncommital genus 

Phyllites. _ 

- Occurrence: Latah formation, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho, collected by H. J. Rust, 

July, 1920. 

Phyflites relatus Knowlton, n. sp. 

Plate XXVIII, Figure 8 

Leaf small, probably about 5 centimeters in length. 

and 2 centimeters in width, ovate-lanceolate; the 

shape of the base is not· known, but the apex is drawn 

out into a long, slender point; the margin is provided 

with numerous rather large, slender, sharp-pointed 

teeth; the midrib is very strong, even to the tip of 

the blade; the number of secondaries can not be made 

out, as the basal portion of the leaf is missing, but 

there must have been nine or ten pairs; they are alternate, mainly irregular or zigzag, slightly curved 

upWard, craspedodrome, often forked, with each 

branch entering a tooth; nervilles !J.Umerous and 

strong, approximately at right angles to the secondaries, both broken and percurrent; finer nervation 

producing an irregular network. 

I am uncertain as to the generic reference for this · 

little leaf. It is· well marked by its thick substance 

an~ l strong nervation, and particularly by its strong 

I 
FLORA OF THE LATAH FO( MATION 49. 

slender teeth, which extend even to the slender peduncle about 18 millimeters in length, somewhat 

acuminate apex. In some ways it suggests !lex, but enlargetl at the top, with what appear to be deflected 

this resemblance is probably only accidental and not portionk of calyx lobes. On this receptacle are oblong, 

a mark of affinity. It seems best under the circum- hard-~h lled, perhaps berry-like seeds or nutlets. These 

stances to place, the leaf in Phyllites for the present, are abof t 5 millimeters long and 4 millimeters broad. 

or until better material can be procured. There i~ a hard outer rim or shell, now carbonaceous, 

Occurrence: Latah formation, Edwards ranch, Stan- and a light-colored inner area that shows faint lines 

ley Hill, Coeur d'Alene, Idaho,. collected by H. J. Rust, and mdrkings. There is some indication of a coluJuly, 1920. mella or axis between the seeds, but this is obscure. 

Phyllites sp. The rumber of these seeds, nutlets~ or whatever 

Plate XXIX, Figure 5 they arr can not be made out with certainty. If it 

This little leaf is the only one observed. It is ap- is assumed that there are four, which seems reasonable, 

parently rather thick, possibly fleshy, and elliptical, it would suggest certain Boraginaceae in which there 

with a rounded, almost truncate base and obtusely are usu lly four 1-seeded nutlets, but if there were a 

acuminate apex; length about 13 millimeters and greater _eumber it might be closer to the Malvaceae. 

width about 7 millimeters; petiole only about 1 milli- The es ~~ ntial characters that remain in doubt make 

meter long as preserved and very broad and thick; further ~peculation hazardous. 

nervation somewhat obscure, but there are five very Occurrence: Latah formation, Edwards ranch, Stanthin veins or ribs that arise in the petiole and then ley Hill,[ Coeur d'Alene, Idaho, collected by H. J. Rust. 

pass up into the leaf, one of them becoming the mid~ July, 19f0. 

rib and the others becoming vague near the middle 

of the blade; there 1 is some evidence that several 

similarly thin veins arise from the middle and upper 

part of the midrib, but it is not conclusive. The finer 

nervation is not distinctly preserved. 

The affinity of this little leaf is hard to determine. 

In size and shape it is very much like the floating 

leaves of some small-leaved species of Potamogeton, 

such as Potamogeton divers1folius Rafinesque and P. 

spirillus Tuckerman, but the nervation is not-quite 

so regular. 

Occurrence: Latah formation, cut No. 2 on OregonWashington Railroad & Navigation Co.'s line, Spokane, 

Wash., collected by Henry Fair and Kirk Bryan, May, 

1923. 

Carpites menthoides Know1ton, n. sp. 

Plate XXVI, Figure 4 

This is a very peculiar fruit that is difficult to 

interpret. It is apparently a globular head approx- -

imately 2 centimeters in diameter, with an axis that 

is small below or toward the point of attachment and 

much swollen above. From all parts of this axis 

radiate narrow, finer, possibly coriaceous bracts, 'or 

something of the kind, that are now concave or possibly they were tubular like the calcyces of the heads of 

certain menthaceous plants such as Monarda. These -

organs seem to be too firm for the flowers of a composite, though that may be their relationship. 

Occurrence: Latah formation, Spokane, .Wash., collected by R. W. Chaney, 1921. University of California Museum No. -f-.!-&. 

Carpites boraginoides Knowlton, n. · sp. 

Plate XXIX, Figure 7 

This little specimen, although seemingly well preserved, is difficult to interpret, because it can not be 

viewed on all sides. It consists of a stout pedicel or 

Carpites polygonoides Knowlton, n. sp. 

Plate XXVI, Figure 7 

As may be seen from the figure, this species is based 

on a cl+ster of some 50 or more detached fruits that 

presum~ly all came from the same plant. They are 

flat, cirbular "seeds" 2 or 3 millimeters in diameter, 

some of! them with a slight point on one side. There 

seems tio be a nucleus in the center, and thus the 

"seed" I ~eems to be winged. The margin. is entire. 

There are no pronounced or interpretable markings 

or ribs T;n the surface. 

Thes~ fruits suggest the fruits of certain of the 

larger-s~eded species of Rumex. Their uniform size, 

with a F: l ntral nucleus and apparent winged margin, 

and abo e all the close grouping of so large a number 

are wha might be expected of the clustered ripe fruits 

of Rumfx, such as Rumex venosus Pursh, R. patentia 

Linne, and R. occidentalis Watson. 

Occu Fence: Latah formation, cut on Spokane, 

Portlan1 & Seattle Railway, Spokane, Wash., collected 

by Henl y Fair and Kirk Bryan, June, 1923. 

Carpites spokanensis Knowlton, n. sp. 

Plate XXVI, Figure 6 

This rganism is difficult to describe, because its 

nature ~nd affinity are not recognized. It is slightly 

obovoid ~ about 12 millimeters long and about 6 millime_ ters t~oad, and attached by a bas_ e that is nearly 

5 mill~ ters broad. At the base there is no apparent 

di:fferen iation between integument and what seems 

to be a 1

1

large ovoid, pointed "seed." From a point 

about 2 ±hillimeters above the base the differentiation is 

complet 1 from what appears to be a thick outer envelope. The central body or "seed" is irregularly 

longitu ally striate. 
50 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

There is another example by the side of the one 

just described that is so folded as to give the impression 

that the outer envelope was two-valved and split 

apart, exposing the "seed." This may not be the 

correct interpretation, but it is given for what it is 

worth. 

Occurrence: Latah formation, cut No.2 on OregonWashington Railroad & Navigation Co.'s line, Spokane, Wash., collected by Henry Fair and Kirk Bryan, 

June 10, 1923. 

Carpites ginkgoides Knowlton, n. sp. 

Plate XXIX, Figure 4 

This specimen is clearly a spherical, hard-shelled 

seed standing on a short, fleshy axis, which is cupshaped at the top, where stands the seed. The seed 

is about 11 millimeters in diameter and was undoubtedly spherical, though now one side is crushed down. 

The shell is about 0.05 millimeter thick and perfectly 

black. There is no evidence of the presence of an 

outer flesh, though this might well enough have been 

present. The seed is now filled with the clay of the 

matrix and is without further differentiation. 

This seed certainly strongly suggests the fruit of 

the living Ginkgo biloba Linne, although it is smaller 

than the usual-sized fruits of this species. As leaves 

of Ginkgo have been found in these beds there is 

warrant for this being the fruit, though there is no 

absolute proof, and hence it seems best to place this 

form in Oarpites pending fuller information. 

Occurrence: Latah formation, cut No.2 on OregonWashington Railroad & Navigation Co.'s line, Spokane, Wash., collected by Henry Fair and Kirk Bryan, 

June 10, 1923. 

Carpites magnifica Knowlton, . n. sp. 

Plate XXIX, Figure 10 

' This specimen is difficult to interpret, although 

seemingly well preserved. It is ovate or ovoid, 

slightly over 4 centimeters in length and 2.3 centimeters in width. It is abruptly rounded below to 

the short, stout point of attachment, within which 

• there are three grooves that become ridges a short 

distance above the base and can be traced upward 

for two-thirds the length of the specimen. A thin 

carbonaceous layer 1 millimeter or more thick surrounds the whole specimen and possibly represents a 

fleshy substance. There are a few irregular ribs or 

corrugations over the body of the specimen, but otherwise the surface is smooth and unmarked. 

This form suggests superficially the nut of a butternut (Juglans cinerea Linne), but the resemblance is 

doubtless fancied rather than real. Its affinity is not 

known. 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected by Don Engdahl for the Spokane Public 

Museum. 

Carpites paulownia Knowlton, n. sp. 

Plate XXIX, Figure 12 

This is apparently a woody capsule, splitting into 

two equal valves. It is oblong or slightly obovoid, 

about 3.3 centimeters in length and 1. 7 centimeters 

in diameter. It stands on a stout, woody axis, which 

is enlarged or saucer-shaped ·at the apex. The axis 

or branch, as well as the enlarged expansion in which 

the capsule sits, is deeply impressed and is now 

changed to a coaly mass. 

The resemblance of this specimen to the mature 

fruit of the living Paulownia is striking. In the living 

species the calyx is trumpet-shaped and deeply 5-cleft, 

with short, moderately acute lobes; it is leathery 

in texture when mature. The capsule is coriaceous, 

ovoid, acute, and loculicidally dehiscent; it is about 

5 centimeters lono- and 2.5 centimeters in diameter. 

Paulownia is a ~onotypic Japanese genus. It is a 

large tree with broad leaves 15 to 40 centimeters long 

and 10 to 20 centimeters wide. It is frequently 

cultivated in the Eastern States and has now escaped 

from cultivation in many places from New York and 

New Jersey southward. 

Only a single fossil species of Paulownia has been 

described-P. europaea Laurent/6 from the Pliocepe 

of Cantal, France, based on a leaf that is almost 

identical with the living P. tomentosa (Willdenow) 

Baillion. The genus has not been detected as fossil 

in North America. It is possible but not certain 

that at least one of the leaves described in this paper 

under the name Ficus? washingtonensis (Pl. XXV) 

may be a leaf of Paulownia~ 

Occurrence: Latah formation, cut on Spokane, 

Portland & Seattle Railway, Spokane, Wash., collected 

· for and contributed by the Spokane Public Museum. 

Branchlet and bud? 

This specimen is 'obscure but is apparently a large 

bud. It is borne on a rather slender stem a little over 

1 centimeter in length and about 2 .millimeters in 

diameter. It is slightly enlarged at the base of the 

"bud," which appears to have relatively large, 

strongly striated scales about. 12 millimeters long and 

5 or 6 millimeters broad. It does not appear to be a 

capsule, th~mgh it may be.· In any event its affinity 

is unrecognized. 

Occurrence: Latah formation, Deep Creek, northwest of Spokane, Wash., collected by Henry Fair, 

June, 1923. 

66 Laurent, L., Faculte sci. Marseille Annales, vol. 14, p. 4, text fig. 1, 1904. 
' . FLORA OF THE LATAH FORM TION 51 

THE FOSSIL DIATOM DEPOSIT AT SPOKANE 

By A LBE RT M ANN 

The shale from Mica, near Spokane, Wash., a sample of which was submitted to me, proves to be moderately rich in fossil diatoms and to differ in several 

respects from any other diatom deposit located in that 

part of the world. There are several diatom beds in 

the Northwest, some covering large areas. All are of 

fresh-water origin, thus contrasting ·with the beds 

in California and Mexico, which are uniformly marine. 

But although the Spokane strata, like the others, 

were laid down in inland lakes, the formation has 

otherwise little similarity . . 

It is not unusual for contiguous diatom formations 

to show dissimilarity in their flora. The subfossil 

deposit of the Klamath Lake district of southern 

Oregon is characteristically local, but neither it nor 

any of the other deposits is as distinctive as this one 

at Spokane. For example, the fossil diatoms of the 

Northwest are largely made up of one species, a 

minute but robust filament-forming diatom, Melosira 

granulata (Ehrenberg) Ralfs, and in some beds it 

composes practically the entire mass. In fact, it may 

be said to characterize the diatom earths of that part 

of the world. But in the Spokane material this 

species is so rare that it is practically negligible; on 

the other hand, the Spokane flora comprises a number 

of species that are strikingly odd and some that have 

never been found before in this country. 

This singularity of the Spokane deposit is apparent 

also in the greatly modified condition of the entire 

diatom mass. Most of the specimens are badly decayed or "rotten," a condition usually met with 

wherever a deposit has been subjected to long periods 

of alkaline corrosion. But in this area the caustic 

action of the water appears to have been somewhat 

operative during the time when the diatoms were 

living and the strata were being laid down, as well as 

during some long subsequent period. For not only 

are the specimens as a whole corroded, but many of 

them were originally misshapen in form and ~urred 

in their ornamentation, indicating that their growth 

took place under unfavorable influences. Such an 

assemblage of crippled and malformed individuals is 

known to be the result of a high percentage of mineral 

salts in the water during the period of diatom growth, 

and several papers on this condition and its effect 

have been published. 

But there is a curious and quite exceptional phase 

of this growth of malformations observable in the 

Spokane material, namely, a tendency in several of 

the species to develop twin specimens-that is to say, 

two complete diatoms, inseparably grown together. 

That such twins represent a real growth product and 

not the subsequent gluing together of two adjacent 

diatoms nor their partial fusion by means of geologic 

I 

heat is easi y seen. An examination of the illustrations 

of such ns which accompany this report and still 

more a miJroscopic study of the specimens them.:;elves 

will make his fact evident. I think it is safe to infer 

that these twin diatoms were caused by some effect of 

certain mireral constitutents of the water acting on 

the diatoms during the plastic period of their vegetative reproJiuction--that io to say, during that wellknown prpcess by which each individupl diatom 

becomes t'fo individuals by the formation of two new 

valves deV]eloped hack to hack within the two older 

valves of .each parent plant. 

From th ~ foregoing facts it is permissible to conclude 

that the Spokane diatom deposit was formed in a 

comparatif ely shallow inland lake,. nominally a 

fresh-water lake but holding in solution a considerable 

amount of mineral constituents, probably derived 

from surfabe drainage and gradually increased by the I 

absence ~ any adequate outlet; furthermo~e, that 

these condlitions continued not only dunng the 

period of I diatom growth, as is indicated by the 

malformat ons of the individuals, but also after the 

deposit had been laid down, as is shown by the corrosion and rdttenness of a great part of the diatom mass. 

The foll win~ is a list of the gene:a and species ~f diatoms fof.nd In the Spokane matenal. It IS practically complete, so far as the sample examined is 

eoncerned; but this d?es not imply that other ~pecies 

might not he found In samples taken some distance 

from the I cation of this one, or from other strata 

above or low this one at the same locality. Diatomists are familiar with the fact that two samples 

taken at Mifferent places in the same hay at the 

present tir±e may show conoiderahle variation in the 

species they contain; and samples taken at exactly 

the same sbot after a lapse of several years are even 

more likelf to be dissimilar. Of course the same 

tendency to variation existed in those remote periods 

of time wt en . the ~iatom beds ~ow represented_ by 

fossils were hmng laid down. It IS therefore ohvwus 

that a list tl f specie.s found in a single fossil sample of 

diatoms is presumably somewhat fragmentary. 

The list contains references to the particular illustrations in well-known works which most accurately 

represent t e specimens found in the Spokane deposit. 

The following abbreviations are used: 

CL Nav. Dliat.-Cleve, P. T., Synopsis of the naviculoid 

diatoms, 1894-1895. 

Donk. Brit. [Diat.-Donkin, A. S., The natural history of the 

British Diatomaceae, 3 pts., 1871-1872. 

Ratt. Rev. p osc.-Rattray, John, A revision of the genus 

Coscinodiscus, 1889. 

Reise F. No .-Grunow, Albert, Reise der Fregatte Novara, 

1857-1859, Bot. Theil, Band 1, Heft 1, 1870. 

Sch. At.-Sdhmidt, A., Atlas der Diatomaceen-Kunde, 1874-

1921. 1 

S. B. D.-Smith, William, A synopsis of the British Diatoma- 1 

ceae, 2 '1ols., 1853, 1856. 

V. H. Syn. Van Heurck, Henri, Synopsis cies diatomees de 

Belgiqu , 188~1885. 
52 SHO.&TER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

References to illustrations are given in the form 

26/29-30-that is, Plate 26, figures 29-30. 

Achnanthes ~ (Achnanthidium) flexella (Brebisson). V. H. Syn., 

26/29-30. 

Actinella brasiliensis Grunow. V. H. Syn., 35/19. 

Amphipleura pellucida var. oregonica Grunow. Cl. Nav. Diat., 

· vol. 1, p. 126; V. H. Syn., 17/14-15. 

# Coscinodiscus subaulacodiscoidalis Rattray. (See Pl. XXX~ fig. 

1.) This ordinarily very rare diatom is rather abundant 

in the ,Spokane material. It seems to have never been 

found before in this country. Its type is figured in Sch. 

At., 57/8 without name and is named in Ratt'. Rev. Cosc., 

p. 521; the specimen was found at Baldjik, on the Black 

Sea. My specimens have only three or four processes. 

Cymbella americana Schmidt. Sch. At., 9/15, 71/78. (See Pl. 

XXX, fig. 2.) 

Cymbella amphicephala Naegeli. Sch. At., 9/56 (no name), 66. 

Cymbella cuspidaia Kuetzing. V. H. Syn., 2/3. Found together 

with yery small and robust varieties. 

Cymbel(a lunula (Ehrenberg) Rabenhorst. Sch. At., 10/42-43. 

The variety found in the Spokane area approaches C. ventricosa Kuetzing, with which this species is sometimes 

united. 

Cymbella partita Mann, n. sp. (See Pl. XXXI, fig. 1.) 

Cymbella sagittarius Mann, n. sp. (See Pl. XXXI, fig. 2.) 

Desmogonium raberhorstianum Grunow. Sch. At., 293/1-11. 

Diatoma grande W. Smith. S. B. D., 40/310. Perhaps this is 

a variety of D. vulgare Bory. 

Diatoma tenue var. hybrida Grunow. V. H. Syn., 50/10-13. 

Diatoma vulgare Bory, type form. Sch. At., 268/24. 

~ Diatoma vulgare var. ehrenbergii Grunow. Sch. At., 268/36. 

-;;¥ Eunotia faba (Ehrenberg) Grunow. Sch. At., 270/33-41. 

Eunotia gracilis (Ehrenberg) Rabenhorst. (See Pl. XXX, fig. 

3.) V. H. Syn., 33/1-2. Shows several interesting malformations. 

Eunotia incisa Gregory. V. H. Syn., 34/35a. 

Eunotia minor (Kuetzing) Rabenhorst. V. H. Syn., 33/2G-21. 

Eunotia parallela Ehrenberg. V. H. Syn., 34/16. Perhaps this 

is a variety of the next. 

Eunotia pectinalis (Kuetzing) Rabenhorst. V. H. Syn., 33/15-

16. 

Eunotia robusta var. diadema (Ehrenberg) Ralfs. V. H. Syn., 

33/12. 

Eunotia robusta var. papilio Grunow. V. H. Syn., 33/8. 

Fragilaria undata W. Smith. S. B. D., 60/377. * Frustulia rhomboides (Ehrenberg) De Toni. (See . Pl. XXXI, 

fig. 3.) V. H. Syn., 17/1-2 (misnamed). 

Gomphonema acuminatum var. suecica Grunow. V. H. Syn., 

23/32 (misnamed). This is essentially the same as G. 

acuminatum var. turris Ehrenberg in Sch. At., 239/34. 

Gomphonema gracile Ehrenberg. Sch. At., 236/16-30, especially fig. 20. 

Gomphonema parvulum Kuetzing. V. H. Syn., 25/10. 

Melosira biseriata Ehrenberg. Sch. At., 180/22. 

Melosira distans Kuetzing. Sch. At., 181/7-11. 

Melosira granulata (Ehrenberg) Ralfs. Sch. At.,.1~1/63. 

Melosira granulata var.=M. crenulata var. tenuts m Sch. At., 

181/56. 

Melosira lyrata Grunow. Sch. At., 181/75. 

Melosira teres Brun? Sch. At., 179/13. Whether or not this 

is Brun's diatom is somewhat uncertain. The reference 

for the type merely says that it occurs in' "Maine"; but 

where, and whether recent or fossil, marine or fresh water, 

is not stated. 4 Melosira undulata (Ehrenberg) Kuetzing. Sch. At., 180/6-9. 

Navicula americana Ehrenberg. V. H. Syn., 12/37. Both 

the typical form and a narrow variety occur here. 

Navicula amphigomphus Ehrenberg. Sch. At., 49/33-34. A 

species sometimes but unwisely united· with N. iridis 

Ehrenberg. 

Navicula angusta Grunow. V. H. Syn., 7/17. 

Navicula bacillum Ehrenberg. V. H. Syn., 13/8. A variet~ 

occurs here that lacks the typical hyaline apical area. 

Navicula commutata Grunow. Sch. At., 45/3'7. 

Navicula contendens Mann, n. sp. (See Pl. XXXI, fig. 4.) 

Navicula dubia Ehrenbe:r:g. (SeeN. iridis var. dubia.) 

Navicula elegans W. Smith. S. B. D., 16/137; Donk. Brit. 

Diat., 4/1. 

Navicula formosa Gregory. Sch. At., 50/14-15. Also a variety 

approaching N. subsalina Donkin. V. H. Syn., 11/6. 

Navicula gibba (Ehrenberg) I)onkin. S. B. D., 19/180; .Sch. 

At., 45/50. This species should not be united with 

N. stauroptera Grunow, which see. 

Navicula gracillima (Gregory) Schmidt. (See Pl. XXX, fig. 4.) 

Sch. At., 45/62. The specimens found agree closely enough 

for specific union with the illustration cited, but there is 

doubt if the name is correctly assigned. Gregory's species 

has no stauros. But the name is preferable toN. mesolepta 

var. angusta, which Cleve offers as a substitute. 

Navicula hilseana (Janisch) Schmidt. Sch. At., 45/65. q'win 

forms of this species are common in the Spokane material. 

Navicula instabilis Schmidt. Sch. At., 43/36. Twin forms of 

this also occur here. The species is close to N. hemiptera 

Kuetzing. 

Navicula iridescens Mann, n. sp. (See Pl. XXX, fig. 5.) 

Navicula iridis Ehrenberg var. subampliata Grunow. (See 

Pl. XXXI, fig. 5.) Sch. At., 49/19. 

Navicula iridis Ehrenberg var. = N. dubia Ehrenberg in Sch. At.,-

49/7 and Donk. Brit. Diat. 5/5. The doubt expressed in 

Ehrenberg's specific name is justified, the form being merely 

a variety of N. iridis. Another variety that occurs here 

is something like N. bisulcata Lagerstedt in Sch. At., 49/15, 

but is much more delicate, narrow, and finely marked and 

measures only 0.091 millimeter in length and 0.013 millimeter in width. · 1 

Navicula major Grunow. Sch. At., 42/10. The true type form 

has not been found in the Spokane material, but there are 

two varieties, one with a very narrow median area and 

one intermediate between this species and N. viridis 

(Nitzsch) Kuetzing. 

Navicula mesotyla (Ehrenberg) J. Schumann. Sch. At., 45/54-55. 

Navicula nodosa Kuetzing. Sch. At., 45/56-58. 

Navicula pauper Mann., n. sp. (See Pl. XXXI, fig. 6.) 

Navicula placentula Ehrenberg. V. H. Syn., 8/26, 28. 

Navicula pontifica Mann n. sp. (See Pl. XXXI, fig. 7.) 

Navicula protrudens Mann, n. sp. (See Pl. XXXI, fig. 8.) 

Navicula pseudo-affinis Mann, n. sp. (See Pl. XXX, fig. 6.) 

Navicula pseudo-bacillum Grunow. V. H. Syn., 13/9. 

Navicula pusilla W. Smith. S. ~· D., 17/145. The specimens 

vary slightly from the type form. 

Navicula radiosa Kuetzing. Sch. At., 47/52. Nearly all the 

specimens are modified into twin forms. 

Navicula reversa Mann, n. sp. (See Pl. XXX, fig. 7.) 

Navicula rupestris (Hantzsch) Schmidt. Sch. At., 45/38-44. 

Malformations and twin forms of this species were found 

abundantly. 

Navicula scutijormis Grunow. Sch. At., 70/62. This species 

bas not been found in America before. It occurs at 

Stavanger, Norway, and in a fossil deposit at Umca, 

Sweden. It is abundant here and affords several varieties. / 

Navicula stauroptera Grunow. Sch. At., 44/41. 

Navicula stauroptera var. = N. parva (Ehrenberg) Van Heurck, 

in V. H. Syn., 6/6 (misnamed). The species should be kept 

separate from N. gibba (Ehrenberg) Donkin, which see. 

Navicula subacuta (Ehrenberg) Schmidt. Sch. At., 43/31 I . 
FLORA b F THE LATAH FOR 53 I 

Navicula substauroneis Mann, n. sp. (See Pl. XXXI) fig. 9.) 

Navicula tabellcria (Ehrenberg) Kuetzing. Sch. At., 43/4. 

Navicula transversa Schmidt. Sch. At., 43/5. The typical 

form occurs and a variety passing into N. major Grunow, 

to which this species is rather too close. 

Navicula viridis (Nitzsch) Kuetzing. Sch. At., 42/13. Twin 

specimens are not uncommon. 

Stauroneis (Navicula) acutissima Mann, n. sp. (See Pl. XXX, 

. fig. 8.) 

Stauroneis (Navicula) anceps Ehrenberg. Sch. At., 242/11-12. 

(See Pl. XXX-I, fig. 11.) . 

>( Stauroneis (Navicula) phoenicenteron Ehrenberg. (See Pl. 

XXXI, fig. 12.) V. H. Syn., 4/2; Sch. At., 242/16. Nearly 

all specimens of this and th~ foregoing species were twin 

forms. 

Surirella bifrons Kuetzing. Sch. At., 22/12. 

Surirella inducta Schmidt, var. Sch. At., 24/25. 

Surirella striatula Turpin. Sch. At., 24/20. This species seems 

- to flourish in waters high in mineral content. It often 

holds its place in lakes that show a gradual increase in 

salinity after other species have been exte:cminated by the 

high percentage of salts. Thus in samples of borings made 

at the site of a prehistoric lake in the Black Rock district 

of Nevada, which slowly changed from fresh water to salt 

water, this species was the last diatom to succumb to the 

growing salinity. It is also sometimes the dominant 

species in such saline waters as Devils Lake, N. Dak., and 

Salt Lake, Utah. 

Tabellaria binalis (Ehrenberg) Grunow. V. H. Syn., 44/23. 

The generic assignment · of this well-known species is 

doubtful. · 

~ Tabellaria fenestrata Kuetzing. S. B. D., 43/317. Most of the 

specimens in the Spokane material are misshapen. 

Tabellaria jlocculosa (Roth) Kuetzing. S. B. D., 43/316. 

Tetracyclus ellipticus (Ehrenberg) Grunow var. latissima. Sch. 

At., 281/2Q-23: 

Tetracyclus ellipticus (Ehrenberg) Grunow var. linearis. Sch. 

At., 281/12. 

Tetracyclus lacustris Ralfs. Sch. At., 269/7-8. 

Tetracyclus rupestris (Brun) Grunow. Sch. At., 297/96, 101. 

The new species are described below. 

Cymbella partita Mann, n. sp. 

Plate XXXI, Figure 1 

Valve moderately bowed, its apices rounded, not 

bent upward or extended; the dorsal side evenly convex, the ventral barely convex and slightly enlarged at 

the middle; an unusually wide, hyaline m,edian area, 

enlarged at the center, extends from that point straight 

to each apex, thereby exactly bisecting the valve, 

whence the specific name here given; rhaphe strong, 

straight, its central ends separated by the large central 

nodule, its apical ends also straight and entering the 

bulbous terminations of the median area; markings of 

fine closely set rows of beading, transverse to . the 

median area. Length, average, 0.184 millimeter; 

width, 0.036 millimeter; 8 lines in 0.01 millimeter. 

This species is near that phase of 0. gastroides 

Kuetzing figured in Sch. At., 9/2, but is too wide to 

be grouped with it as a variety. It occurs in this 

material in both the normal and the twin conditions. 

85658°-26--5 

I Cymbella sagittarius Mann, n. sp. 

Plate XXXI, Figure 2 

Valve 'th extended and acute ends, the dorsal side 

strongly onvex in its middle part and rapidly tapering 

to the en s; the ventral side slightly convex from end 

to end; r~aphe median, straight; mar.kings of very fine 

beaded r~ws, the beads so spaced as to show both 

t.ransvers , and longitudinal. interlines; median area 

wide, tap ring, distended at the middle, especially on 

the ventr I side, where it nearly reaches the margin; 

central nodule prominent. Length, 0.114 millimeter; 

width, 0.022 millimeter; 16 lines in 0.01 millimeter. 

This graceful and sharp-ended species is quite distinct from any known form. Its name refers to the 

perfect bow formed by the rhaphe and the dorsal 

margin. 

Navicula contendens Mann~ n. sp. 

Plate XXXI, Figure 4 

Valve fusiform, with slightly enlarged, rounded 

apices; markings of strong, closely set moniliform 

costae, radial at the middle of the valve, reversed near 

and at the apices; hyaline median area widely 

distended at the middle of the valve, tapering to near 

the apices, where the markings closely approach the 

rhaphe; outer ends of the rhaphe slightly hooked and 

surrounded by small hyaline areas, middle ends of 

the rhaphe bent to one side. Length, 0.078 millimeter; 

width, 0.0194 millimeter; 11.Slines in 0.01 millimeter. 

This species resembles the one figured in V. H. Syn., 

6/17, incorrectly named as a variety of N. legumen 

Ehrenberg. Clev~ (N av. Diat., II, p. 84) groups it 

with the similar form in Sch. At., 45/30, the less 

similar form in Sch. At., 45/29, and N. scythica Pan: 

tocsek in Pant. Hung. Diat., III, 23/335, under 

Pinnularia subsolaris Grunow. AI though the figure 

in Sch. At., 45/30, might be united with the others 

above mentioned, the species here represented is too 

dissimilar to admit of the same assignment. 

Navicula iridescens Mann, n. sp. 

Plate XXX, Figure 5 

Valve delicate, narrow, spindle-shaped, with slightly 

protruding ends that are capped at the tip with a 

lunate thickening, like the other members of the N. 

iridis group; markings of fine, closely set beaded lines, 

transverse and reaching close to the rhaphe, except at 

the center, wher/e there is a small diamond-shaped area; 

a single wavy line close to each side traverses the 

entire length of the valve; rhaphe perfectly straight, 

not bent on hooked at the center. Length, 0.128 

millimeter; width, 0.021 millimeter; 22 lines in 0.01 

millimeter. It has a remote resemblance to the unnamed form shown in Sch. At., 49/40. 
54 SHORTER CONTRIBUTIONS TO GENERAL GEOLOGY, 1925 

Navicula pauper Mann, n. sp. 

,Plate XXXI, Figure 6 

Valve narrow, almost linear, slightly tapered to the 

blunt, enlarged ends, which are thickened internally 

into a lunate cap, characteristic of the N. iridis group; 

markings confined to a narrow, somewhat ragged 

. band of fine, beaded, transverse lines along each side, 

· the beads on the inner edge of each band being larger 

than the rest; rhaphe strong, straight, its middle ends 

not bent or enlarged. Length, average, 0.110 millimeter; width, 0.016 millimeter; 7 lines in 0.01 millimeter. The specimens showed many cases of malformation and twin forming. 

Navicula pontifica Mann, n. sp. 

Plat e XXXI, Figure 7 

Valve elongated, robust, barely tapering from the 

slightly distended mi<idle to the rounded ends; markings of strong, smooth costal lines, radially oblique 

at the middle and halfway to the ends, then reversed 

oblique, reduced to mere traces at the ends and wanting at the middle, thereby producing a broad, somewhat flaring stauros; a single wavy line runs the length 

of the valve on either side close to the margin; longitudinal median area fully one-third the width of the 

valve, dilated at the ends; rhaphe straight, its central 

ends slightly bent, its apical ends strongly hooked. 

Length, 0.189 millimeter; width, 0.026 millimeter; 10 

lines in 0.01 millimeter. Distinguished from minute 

specimens of N. major readily by its strong stauros. 

Navicula protrudens Mann, n. sp. 

Plate XXXI, Figure 8 

Valve very convex, narrow, elongated, dilated at 

the middle, otherwise straight, wit;h rounded, not 

swollen ends; markings of fine, transverse, beaded 

lines, reaching almost to the rhaphe except at the 

middle, where there is a large diamond-shaped median 

area; a strong, longitudinal line running midway 

between the rhaphe and each side; rhaphe straight, 

its outer ends terminating in large protuberant beads, 

whence the specific name. Length, average, 0.082 

millimeter; width, 0.012 millimeter; 9 lines in 0.01 

millimeter. 

Navicula pseudo-affinis Mann, n. sp. 

Plate XXX, Figure 6 

Valve elongated, gently narrowed from the middle 

to near the ends, then abruptly compressed, so that 

the last part at each end is protuberant, with wedgeshaped apex; markings of fine and closely set rows 

of slightly elongated beads, the rows radial at the 

center and oblique to near each end, where they become 

transverse, not reaching i'nward to the rhaphe _line, 

but leaving a wide longitudinal median area, dilated 

at the center of the valve; a distinct line running 

longitudinally on each side near the margin until the 

two merge into the two forks extending inward from 

a hyaline area at each apex of the valve; rhaphe strong, 

straight, its inner ends bent into minute hooks, both 

turned toward the same side. Length, 0.168 millimeter; width, 0.031 millimeter; 12 lines in 0.01 millimeter. 

The nearest relatives are the unnamed form shown 

in Sch. At., 49/1, called N. ajjinis yar. genuina -Cleve 

in Fricke's index of that work; also fig. 19 on the same . 

plate, having the questionable name N. firma var. 

subampliata Grunow. But both differ from this 

species in the direction and composition of their 

markings. 

.Navicula reversa Mann, n. sp. 

Plate XXX, Figure 7 

Valve broad, stout, with practically parallel sides 

and rounded ends; marked with closely set and fine 

beading in strongly divergent, wavy rows at the 

middle, which continue radially oblique to near the 

ends, then reversing to strongly convergently oblique, 

as in N. oblonga Kuetzing; central arrea large, rectangular, merging into a narrow median line running 

to the apices; rhaphe slightly undulate, its two middle 

ends joined across the central nodule by a thin line, 

its two terminal ends hooked. Length,· 0.107 millimeter; width, 0.022 millimeter; 8 lines in 0.01 millimeter. 

This approaches several known species but without 

sufficient nearness to warrant a union: N. commutata 

Grunow as figured in Sch. At., 45/35, and the varie~y 

of N. major Grunow shown in Sch. At., 42/8_:.._a good 

illustration of how a species may serve as a bridge be- rtween two quite dissimilar forms. It stands even nearer 

to the form which Grunow calls N. (Pinnularia) leptogonglya Ehrenberg in Sch. At., 45/26 and which 

Schmidt there claims to be quite different, and rightly · 

so. I have therefore found it convenient to assign .a 

name. 

Navicula substauroneis Mann, n~ sp. 

Plate XXXI, Figures 9, 10 

Valve narrow, lanceolate, sides straight from the 

middle to the blunt, rounded ends; markings of 

strongly beaded lines, barely oblique to near the ends, 

there transverse, reaching nearly to the rhaphe but 

leaving an evident central area extended into a 

strong stauros across the middle to the sides; rhaphe 

delicate, its inner ends slightly bent and bead-tipped, 

its outer · ends hooked. Length, average, 0.105 

millimeter; width, 0.015 millimeter; 10 lines in 0.01 

millimeter. 
FLORA qF THE LAT:AH FORMAT10N 55 

Stauroneis (Navicula) acutissima Mann, n. sp. 

Plate XXX, Figures 8, 9 

Valve narrow, lanceolate; with much elongatecJ, 

needle-sharp ends and slightly undulate sides; markings of very fine, closely set beaded lines, somewhat 

radially oblique to the long axis, reaching f:r;-om the 

sides to the rhaphe; a broad, slightly depressed 

· stauros across the middle; rhaphe straight, delicate, 

each half beginning at the stauros and running tq 

• 

the extreme tip of the valve; the tips thickened 

internally as inS. acuta W. Smith,· so that the inner 

cavity of the diatom is remote from the very pointed 

tips. Length, 0.070 millimeter; width, 0.010 milli.:. I 

meter; 29 liJ).es in 0.01 millimeter. 

It would be permissible to classify this as a very 

wide variety of ·s. smithii Grunow, but its larger· ·: 

size, much more acicular shape, . and broad stauros 

are in favor of a separate name. Many malformed 

specimens were found, one of which is,;here illustrated. 
PLATES VIII-XXXI 

57 
PLATE VIII 

Page 

FIGURE 1. Archaeomnium patens E. G. Britton. Cut No. 1, Spokane, Portland & Seattle Railway, Spokane, Wash. U.S. 

Nat. Mus. No. 36869_~----------------------------------------------------------- ----------- 24 

2. Same, X 3. 

3. Polytrichites spokanensis E. G. Britton. Deep Creek northwest of Spokane, Wash. U.S. Nat. Mus. No. 36870_ 24 

4. Same, X 3. 

5. Moss, genus and species? Deep Creek, northwestofSpokane, Wash. U.S. Nat. Mus. No.3687L______ __ 24 

6. Same, X 3. 

7. Lycopodium hesperium Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. 

No. 36872-------------------------------------------------------------------------------------- 24 

8. Libocedrus praedecurrens Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. 

Nat. Mus. No. 36873_____________________________________________________________________________ 28 

9. Pinus sp. Well near Mica, southeast of Spokane, Wash. U.S. Nat. Mus. No. 36874____________________ 26 

10. Ginkgo adiantoides (Unger) Heer. Third cut on Spokane, Portland & Seattle Railway, Spokane, Wash, U. S. 

Nat. Mus. No. 37192------------------------------- - - - ----------------------------------------- 25 

11. Ginkgo adiantoides (Unger) Heer. Fivemile Prairie, near Spokane, Wash. Specimen in Public Museum, 

Spokane----------------------------------------------------------------------------------~---- 25 

58 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE VIII 

XI 

1 

5 

7 

10 XI 

3 

6 

X3 

8 9 11 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE IX 

4 

3 

1 

2 

6 

7 

10 

11 8 9 

FOSSILS OF LATAH FORMATION 
PLATE IX 

Page 

FIGURE 1. Equisetum, underground stem. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

~us. No. 36875-------------------------- ---------------------------------- --------------------- 24 

2. Taxodium dubium (Sternberg) Heer. Deep Creek half a mile above mouth, northwest of Spokane, Wash. 

U.S. Nat. ~us. No. 36876---------------------------------------------------------------------- 27 

3-6. Sequoia langsdorfii (Brongniart) Heer. Figs. 3, 4, 5, from Deep Creek half a mile above mouth, northwest . 

of Spokane, vVash. (U. S. Nat. ~us. Nos. 36880, 36881, 36882); fig. 6 from Edwards ranch, Stanley Hill, 

Coeur d'Alene, Idaho (U.S. Nat. ~us. No. 36879)-------------------------------------------------- 26 

7-9. Taxodium dubium (Sternberg) Heer. Fig. 7 from Elko, Nev. (U.S. Nat. ~us. No. 36883) (introduced for comparison); fig. 8 from Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho (U. S. Nat. ~us. No. 36878); fig . . 

9 from cut on Spokane, Portland & Seattle Railway, Spokane, Wash. (U. S. Nat. ~us. No. 36877) ________ · 27 

10. Fern, fragment, X 2. Cut No. 2, Oregon-Washington Railroad & Navigation Co.'s line, Spokane, Wash. 

U.S. Nat. ~us. No. 36884_______________________________ _______ _________________________________ 24 

11. Typha? sp. Spokane, Wash. Specimen in University of California, No. ·i-/sVs--------------------------- 28 

59 
PLATE X 

Page 

FIGURE 1. Arisaema hesperia Knowlton. Deep Creek, northwest of Spokane, Wash. U. S. Nat. Mus. No. 36885 ___ _ 29 

2. Taxodium dubium (Sternberg) Heer. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. 

Nat. Mus. No. 36886----------------------------------------------------------------------------- 27 

3. Tumion bonseri Knowlton. Spokane, Wash. U.S. Nat. Mus. No. 36887-------------------------------- 25 

4. Taxodium, male aments. Deep Creek, northwest of Spokane, Wash. U.S. Nat. Mus. No. 36888__________ 28 

5. Potamogeton sp. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U.S. Nat. Mus. No. 36889_ _ 29 

6. Same, X 2. 

7. Grass, leaf. Cut on Chicago, Milwaukee & St. Paul Railway near Spokane, Wash. U.S. Nat. Mus. No. 36890_ 29 

8. Grass?, genus? Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U.S. Nat. Mus. No. 36891__ 29 

9. Same, X 3. 

10. Liquidambar, fruit, X 2. Cut No. 2, Oregon-Washington Railroad & Navigation Co.'s line, Spokane, 

Wash. U.S. Nat. Mus. No. 36892________________________________________________________________ 42 

60 
U. S . GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE X 

5 

1 

2 

7 

6 

3 

4 

10 

XI 

9 8 

FOSSILS OF LATAH FORMATION 
U . S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 14~ PLATE XI 

2 

FOSSILS OF LATAH FORMATION 
PLATE XI 

Page 

E'IGURES 1, 2. Salix inquirenda Knowlton. Twelfth Avenue and Thor Street, Spokane, Wash. U. S. Nat. Mus. Nos. 

36893, 36894__________________________________________________________________________________ 32 

61 
PLATE XII 

Page 

FIGURES 1, 2. Salix dayana Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. Edwards ranch, 

Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. Nos. 36895, 36896_____________________________ 32 

3. Salix sp. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. No. 36897 _ _ _ _ _ _ _ _ _ _ _ _ _ _ 33 

4. Salix elongata, 0. Weber. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. No. 36898__ 32 

5. Salix perplexa Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36899 _____________ ~---------- ---- ---- ------- --- -- --- -- -- -------- ------------~ ----------- 32 

6. Salix bryani Knowlton. Cut on Chicago, Milwaukee & St. Paul Railway near Spokane, Wash. U. S. 

Nat. Mus. No. 36900 _ -------------- --- ---------------------------------------~--------- -- ----- 33 

7. Salix remotidens Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. No. 3690L _____ ____________ -. _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 32 

8--10. Populus heteromorpha Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. 

Nat. Mus. Nos. 36902, 36903, 36904_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ ___ _ _ _ _ _ _ _ __ _ _ _ _ __ _ _ __ _ _ __ _ _ __ _ __ _ __ __ __ _ 30 

62 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XII 

1 3 

2 

4 

5 

8 

7 9 10 

FOSSILS OF LATAH FORMATION 
U . S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XIII 

1 

2 

3 4 

5 

6 7 

FOSSILS OF LATAH FORMATION 
PLATE XIII 

Page 

FIGURES 1-7. Populus heteromorpha Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. 

Nat. Mus. Nos. 36905-3691 L _________________________________________________ ______ __________ - - 30 

63 
PLATE XIV 

Page 

'FIGURES 1-3. Populus heteromorpha Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. 

Nat. Mus. Nos. 36912, 36913, 36914_______________________ ___________________________ ___ __ __ ____ 30 

4-7. Populus lindgreni Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. Nos. 

36915-36918___________________________________________________________________________________ 31 

64 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XIV 

1 2 3 

4 

5 

6 7 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XV 

1 

4 

2 5 

FOSSII.B OF LATAH FORMATION 
PLATE XV 

Page 

FIGURE 1. Populus washingtonensis Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. 

No. 36919_ _____ ___ _______ ____ _____ __ __ __ ______ _________ ____ ___ ______ __ __ _______ _________________ 31 

2. Populus fairii Knowlton. Spokane, Wash. U . S. Nat. Mus. No. 36920__________ ______ __ ___ _____________ 30 

3-5. Po p1tlus heteromorpha Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. Nos. 36921-36923--------------------------------------------------------------------------- 30 

85658°-26--7 65 
PLATE XVI 

Page 

FIGURES 1-3. Populus fairii Knowlton. Spokane, Wash. U.S. Nat. Mus. Nos. 36924-36926-------··--------- ------- 30 

66 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XVI 

1 

2 

3 

FOSSILS OF LATAH FORMATION 
~. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XVII 

4 

3 

5 6 

FOSSILS OF LATAH FORMATION 
PLATE XVII 

Page 

FIGUREi:i 1, 2. Betuta? largei Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

Nos. 36927, 36928_______________ ______ __ __ ______________ ___ _____________ ______________________ 34 

3. Betula thor Knowlton. Twelfth Avenue and Thor Street, Spokane, Wash. U.S. Nat. Mus. No.· 36929____ 35 

4. Betulajairii Knowlton. Cut on Chicago, Milwaukee & St. Paul Railway near Spokane, Wash. U.S. Nat. 

Mus. No. 36930------------------------ - - - ----------- - - - -- -- ---------------- -- --- ------- ------ 33 

5, 6. Betula heteromorpha Knowlton. Fig. 5, Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho (U.S. Nat. Mus. 

No. 36931). Fig. 6, Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. (U. S. Nat. Mus. 

No. 36932)----------------------------------------------- ---------------- -- -- -------- ------ 34 

67 
PLATE XVIII 

Page 

FIGURE 1. Betula bryani Knowlton. Twelfth Avenue and Thor Street, Spokane, Wash. U.S. Nat. Mus. No. 36933_____ 34 

2. Betula nanoides Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. No. 36934__ 34 

3-5a. Alnus; pistillate cones. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. Nos. 36935, 

36936, 36937. Figure 5a twice enlarged ____ __ __ ____ __________________________________________ __ """'____ 33 

6. Ulmus speciosa Newberry. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36938--------------------------------------------------------------------------------------- 39 

7, 8. Castanea castaneaefolia (Unger) Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. 

U.S. Nat. Mus. Nos. 36939. 36940----------------------------------------------------------------- 35 

68 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XVIII 

3 4 

7 

6 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XIX 

2 

3 

1 

5 

G 

7 8 9 

FOSSILS OF LATAH FORMATION 
PLATE XIX 

Page 

FIGURE I. Castanea castaneaefolia (Unger) Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. No. 36941_ __ _ _ _ ___ _ _ __ _ ___ _ _ _ _ __ _ _ __ __ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ __ _ __ __ __ _ _ ____ _ ___ _ __ 35 

2. Ulmus fernquisti Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36942_______________________________________________________________________________________ 39 

3. Quercus spokanensis Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. No. 36943__________________________________________________________________________________ 37 

4, 5. Quercus merriami Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. Nos. 

36944, 36945___________________________________________________________________________________ __ 35 

6. Quercus praenigra Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. No. 

36946_____________________________________________________________________ ____________________ __ 37 

7. Quercus sp. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. No. 36947___ ____ _______ 37 

8, 9. Quercus, acorn. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U.S. Nat. Mus. No. 36948__ 39 

69 
PLATE XX 

Page 

FIGURES 1-4. Quercus cognatus Knowlton. Figures 1, 2, 4, Spokane, Wash.; Figure 3, Edwards ranch, Stanley Hill, Coeur 

d'Alene, Idaho. U.S. Nat. Mus. Nos. 36949, 36950, 36951, 36952__________________________________ 36 

70 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XX 

2 

1 

3 

4 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XXI 

5 

1 

7 

3 X2 

9 

FOSSILS OF LATAH FORMATION 
PLATE XXI 

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FIGURES 1, 2. Quercus cognatus Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho; Spokane, Wash. U. S. 

Nat. Mus. Nos. 36953, 36954 ___________________________________________ ____ __ __ _______ -- _ _ _ __ _ _ 36 

3, 4. Quercus rustii Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. Nos. 

36955, 36956___ _______________________________________________________________________________ 36 

5-7. Quercus payettensis Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. Nos. 

36957, 36958, 36959____________________________________________________________________________ 37 

8. Quercus, acorn. Edwards ranch, Stanley Hill, Coeur d 'Alene, Idaho. U.S. Nat. Mus. No. 36961_______ 39 

9. Same, X 2. 

10. Quercus, cup. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U.S. Nat. Mus. No. 36960__ 39 

71 
PLATE XXII 

Page 

FIGURE 1. Quercus chaneyi Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36962_______________________________________________________________________________________ 38 

2. Quercus cf. Q. pseudo-lyrata Lesquereux. One mile west of Shelley Lake, 10 miles east of Spokane, Wash. U. S. 

Nat. Mus. No. 36963_____ __ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ _ _ __ _ _ _ 36 

3. Quercus simulata Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36964_______________________________________________________________________________________ 38 

4. Quercus simulata Knowlton. Deep Creek, northwest of Spokane, Wash. U.S. Nat. Mus. No. 36965_________ 38 

5, 6. Diospyros? microcalyx Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. NOS. 36966, 36967---------------------------------------------------------------------------- 46 

7. Liquidambar pachyphyllum Knowlton. Cut No. 2 on Oregon-Washington Railroad & Navigation Co.'s line, 

Spokane, Wash. U.S. Nat. Mus. No. 36968________________________________________________________ 42 

8. Quercus obtusa Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36969---------------------------- ------------------------ - ---------------------------------- 38 

9. Quercus sp. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. No. 36970_______________ 37 

72 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XXII 

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3 

1 

5 

6 

8 9 4 

FOSSILS OF LATAH FORMATION 
U . S . GE OL O GICAL SUR VE Y PR ESS ION ~ PAPER 140 PLATE XXIII 

5 

4 

1 

6 2 

3 

FOSSILS OF LATAH FORMATION 
PLATE XXIII 

Page 

FIGURES 1, 2. Laurus princeps Heer. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36971. (Fig. 2 counterpart of fig. 1, given to show nervation.)______________________ ___________ _ 41 

3. Laurus princeps Heer. Well at Mica, southeast of Spokane, Wash. U.S. Nat. Mus. No. 36972_____ _____ 41 

4-6. Laurus similis Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

Nos. 36973, 3697 4. (Fig. 5 counterpart of fig. 4, given to show details of nervation.) _________________ - 41 

85658°-26--8 73 
PLATE XXIV 

Page 

FIGURE 1. Laurus grandis Lesquereux. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

No. 36975____ __ ______ ____ _____ _____________________________ _______________ __ __________________ __ 41 

2. Laurus similis Knowlton. Cut on Chicago, Milwaukee & St. Paul Railway near Spokane, Vvash. Specimen 

in University of California, No. -.l-l•l-rP?J- --- ------------------------------------------------ - ---------- 41 

3. Magnolia dayana Cockerell. Spokane, Wash. U.S. Nat. Mus. No. 36976__________ ___ ______ _____________ 41 

4. Prunus rustii Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. No. 36977____ 43 

5. Prunus rustii Knowlton. Cut No. 2, Chicago, Milwaukee & St. Paul Railway, Spokane, Wash. U. S. Nat. 

Mus. No. 36978 __________ __ ____________ ___ __ ______ _____ ____________ - ----------------------------- 43 

6. Hydrangea bendirei (Ward) Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. · U. S. 

Nat. Mus. No. 36979 ____ ___ __ ~ ___________________ ___ - _-------- __ - - --- -- -- -- - --- ---------------- _- - 42 

74 
PLATE XXV 

Page 

Ficus? wa:shingtonensis Knowlton. Spokane, Wash. U. S. Nat. Mus. No. 369 80 __________________ ------------------.. 40 

75 
PLATE XXVI 

Page 

FIGURES 1-3. Ficus? washingtonensis Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. 

Nos. 36981, 36982, 36983_ _ __ _ __ _ ___ __ __ ____ __ ___ ______ __ __ __ ___ ___ __ _____ __ ___ _______ ___ _ ______ 40 

4. Carpites menthoides Knowlton. Spokane, Wash. Specimen in University of California, No. ·l·l·l:Ps-------- 49 

5. Equisetum, underground stems. Deep Creek, northwest of Spokane, Wash. U. S. Nat. Mus. No. 36984____ 24 

6. Carpites spokanensis Knowlton. Cut No.2, Oregon-Washington Railroad & Navigation Co.'s line, Spokane, 

'\Vash. U.S. Nat. Mus. No. 36985_________________________________ __ ___ ____ _____ _____________ __ 49 

7. Carpites polygonoides Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. 

Nat. Mus. No. 36986_ _ _ _ _ _ _ _ _ _ _ __ _ _ _ __ _ __ _ _ _ _ _ _ _ ___ __ _ _ ___ _ _ _ __ _ __ _ __ __ _ _ _ ___ __ _ ____ _ __ _______ 49 

8. Phyllites sophoroides Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. 

No. 36987------------------------------------------------------------------------------------ 48 

76 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XXVI 

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6 

4 5 

7 

8 

3 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XXVII 

3 

1 4 

5 

2 6 

FOSSILS OF LATAH FORMATION 
PLATE XXVII 

Page 

FIGURE 1. Magnolia sp. Twelfth Avenue and Thor Street, Spokane, Wash. U.S. Nat. Mus. No. 36988__________ ____ 41 

2. Acer chaneyi Knowlton. Spokane, Wash. Type in University of California, No. -ll9V7J:--- ------------------ 45 

3. Acer bendirei Lesquereux. Well at Mica, southeast of Spokane, Wash. U.S. Nat. Mus. No. 36989________ __ 45 

4. Acer minor Knowlton. Deep Creek, northwest of Spokane, Wash. U.S. Nat. Mus. No. 36990____________ __ 45 

5. Rhus typhinoides Lesquereux. Clay pit 2 miles south of Vera, Wash. U.S. Nat. Mus. No. 36991___________ 45 

6. Diospyros andersonae Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

l\1 us. No. 36992 ______________________________________________________________________ __ --- _ _ _ _ _ _ _ 46 

77 
PLATE XXVIII 

Page 

FIGURE 1. Acer merriami Knowlton. Well at Mica, southeast of Spokane, Wash. U.S. Nat. Mus. No. 36993__________ 45 

2. Celastrus jernquisti Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. No. 36994_______________________________________________________________ ___________________ 44 

3-5. Sophora alexanderi Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. Nos. 

36995, 36996, 36997. (Fig. 3a is same as fig. 3, X 2.)------------------------------------------------- 43 

6. Sophora spokanensis Knowlton. Deep Creek, northwest of Spokane, Wash. U.S. Nat. Mus. No. 36998______ 44 

7, 7a. Robinia? sp. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. No. 36999. 

(Fig. 7a is same as fig. 7, X 2.)--- - - - ------------- ------- ------------------------------------------- 44 

8. Phyllites relatus Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. No. 37000_ 48 

9, 9a. Vaccinium salicoides Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U.S. Nat. Mus. No. 3700L 46 

10. Meibomites lucens Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U.S. Nat. Mus. 

No. 37002--------------------------------------------------------------------------------------- 44 

78 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XXVIII 

3a 

5 

8 

2 9a 9 10 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPEH. 140 PLATE XXIX 

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1 

7 

6 

4 

9 

5 

3 8 

10 12 13 

FOSSILS OF LATAH FORMATION 
PLATE XXIX 

Page 

FIGURE 1. Liquidambar pachyphyllum Knowlton. Cut on Oregon-Washington Railroad & Navigation Co.'s line, Spokane, 

·wash. U.S. Nat. Mus. No. 37003_________________________________________________________________ 42 

2. Phyllites peculiaris Knowlton. Twelfth Avenue and Thor Street, Spokane, Wash. U.S. Nat. Mus. No. 37004_ 48 

3. Phyllites amplexicaulis Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. No. 37005---------------------------------------------------------------------------------- 47 

4. Carpites ginkgoides Knowlton. Cut No. 2, Oregon-Washington Railroad & Navigation Co.'s line, Spokane, 

Wash. U.S. Nat. Mus. No. 37006----------------------------------------------------------------- 50 

5. Phyllites sp. Cut No.2, Oregon-Washington Railroad & Navigation Co.'s line, Spokane, Wash. U. S. Nat. 

~dus. No. 37001---------------------------------------------------------------------------------- 49 

6. Phyllites crustacea Knowlton. Well at Mica, southeast of Spokane, Wash. U.S. Nat. Mus. No. 37008_______ 47 

7. Carpites boraginoides Knowlton. Edwards ranch, Stanley Hill, Coeur d'Alene, Idaho. U. S. Nat. Mus. No. 

37009------------------------------------------------------------------------------------------- 49 

8. Eq1.tisetum, underground stem. Deep Creek, northwest of Spokane, Wash. U.S. Nat. Mus. No. 37010_________ 24 

9. Cercis? spokanensis Knowlton. Deep Creek, northwest of Spokane, Wash. U.S. Nat. Mus. No. 37011_____ 43 

10. Carpites magnifica Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

r~o. 37012--------------------------------- -- ---------------- ------------------------------------ 50 

11. Malva? hesperia Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. r~o. 37013_______________________________________________________________________________________ 47 

12. Carpites paulownia Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. 

Mus. No. 37014 ___________________________________________________ ---- __ -------------------------- 50 

13. Phyllites pardeei Knowlton. Cut on Spokane, Portland & Seattle Railway, Spokane, Wash. U. S. Nat. Mus. 

l~O. 37015--------------------------------------------------------------------------------------- 48 

79 
PLATE XXX 

FIGURE 1. Coscinodiscus subaulacodiscoidalis R.attray, X 930. 

Page 

2. Cymbella americana A. Schmidt, twins, X 550. 

3. Eunotia gracilis (Ehrenberg) R.abenhorst, abnormal form, X 870. 

4. Navicula gracillima (Gregory) A. Schmidt, X 610. 

5. Navicula iridescens Mann, n. sp., X 730---- ------ ----- -------- ---------------------------------------- 53 

6. Navicula pseudo-affinis Mann, n. sp., X 550_____ ___________ ________ ______ __ ____________________________ 54 

7. Navicula reversa Mann, n. sp., X 840_____ ____________ _____ ____________________________________________ 54 

8. Stauroneis acutissima Mann, n. sp., X 810------------------------------------------------------------- 55 

9. Same, abnormal form, X 810. 

80 
U. S. GEOLOGICAL SURVEY 

PROFESSIONAL PAPER 140 PLATE XXX 

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1 

8 2 9 

4 

FOSSILS OF LATAH FORMATION 
U. S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 140 PLATE XXXI 

11 

5 10 

4 

6 7 

1 

2 

8 

3 

12 

FOSSILS OF LATAH FORMATION 
PLATE XXXI 

Page 

FIGURE 1. Cymbella partita Mann, n. sp., X 500--------------------------- - - ------------·------------------------ 53 

2. Cymbella sagittarius Mann, n. sp., X 570_ _ ___ _____ _ ____ __ ___ _ _ _ __ _ _ __ _ _ _ _ _ ___ __ _ _ __ _ _ ___ _ _ ___ _ __ _ _ __ _ _ 53 

3. Frustulia rhomboides (Ehrenberg) De Toni, twins, face view, X 860. 

4. Navicula contendens Mann, n. sp., X 800------ ----------~----- --------------------------------- ... ·-- 53 

5. Navicula iridis Ehrenberg, delicate dwarf variety, X 650. 

6. Navicula pauper Mann, n. sp., X 540---------- ----------------- ----------------------- --------------- 54 

7. Navicula pontifica Mann, n. sp., X 450--------- ------------------------------------------------------- 54 

8. Navicula protrudens Mann, n. sp., X 710--------- --------------- - - -------------------------:----------- 54 

·9. Navicula substauroneis Mann, n. sp., X 680----- ------------------------------------------------------- 54 

10. Same, twins, girdle view, X 440. 

11. Stauroneis anceps Ehrenberg, twins, girdle view, X 620. 

12. Stauroneis phoenicenteron Ehrenberg, twins, face view, X 410. 

85658°-26--9 81