DEPARTMENT OF THE INTERIOR

BULLETIN

OF THE

UNITED STATES

GEOLOGICAL SURVEY

No. 56

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1889
I
UNITED STATES GEOLOGICAL SURVEY

J. W. POWELL, DIRECTOR

FOSSIL WOOD AND LIGNITE

OP THE

POTOMAC FORMATION

BY

FRANK HALL KNOWLTON

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1889

CONTENTS.

Pag&

Letter of transmittal...................... .......... .................... i>

Introduction...... .......................................................... 11

Value of the study of internal structure, -with brief review of its progress. 11

Geologic and geographic distribution of the Potomac formation............... 38

^be organic remains and their mode of occurrence........................... 39'

Systematic description of lignite ............................................ 41

Systematic description of silicified species................................... 43

Cupressinoxylon Goppert................ .....<>........................... 43

Cnpressinoxylon pulchellum, n.sp........................................ 45

Cupressinoxylon McGeei,n.sp ............'.............................. 46

Cupressinoxylon Wardi,n.sp............................................ 4&

Cupressinoxylon Columbianum,n.sp .................................... 49

Arancarioxlon Kraus............................................. ..f .... 50

. Araucarioxylon Virginianum.n. sp....................................... 50

ILLUSTRATIONS.

Page.

PLATE I. Lignite .......................................................... 54

II. Cupressinoxylon pnlchellum, n.sp.,a Cupressinoxylon McGeei,

n.sp.......................................................... 56

III. Cupressinoxylon McGeei, n.sp ............................. .... 58

IV. Cupressinoxylon Wardi, n. sp., and Cupressinoxylon Columbianum, n.sp ................................................... 60

V. Cupressinoxylon Wardi, n. sp., and Cupressinoxylon Columbianum, n.sp !............... ................................... 62

VI. Cupressinoxylon Columbianum,n.sp ............................ 64

VII. Cupressinoxylon Columbianum, n. sp., and Araucarioxylon Virginianum, n. ep................... ......................... 66

LETTER OF TRANSMITTAL

DEPARTMENT OP THE INTERIOR, 

U. S. GEOLOGICAL SURVEY, DIVISION OF PALEOBOTANT,

Washington, February 23,1889,

SIR: I have the honor to transmit herewith the manuscript of a paper 

by Prof. F. H. Knowlton, Assistant Curator of Botany and Fossil 

Plants of the U. S. National Museum, on the Fossil Wood and Lignite 

of the Potomac Formation, and to request its publication as a bulletin 

of the U. S. Geological Survey. 

Very respectfully yours,

LESTER F. "WARD,

Geologist in charge. 

Hon. J. W. POWELL,

Director V. S. Geological Survey.

FOSSIL WOOD AND LIGNITE OF THE POTOMAC

FORMATION.

BY F. H. KNOWLTON.

INTRODUCTION.

TALUE OF THE STUDY OF INTERNAL STRUCTUEE, WITH BRIEF REVIEW OF ITS PROGRESS.

The value of paleontology to stratigraphy is so generally recognized 

that it hardly needs to be emphasized. Heretofore, however, the evidence most relied on has been derived from a study of animal fossils, 

the reason being chiefly that there have been more paleozoologists 

than paleobotanists and more data of a paleozoologic character have 

been accessible. But paleobotany is gradually coming into prominence, 

and within the last half century, particularly within the last decade, it 

has shown a wonderfully increased development. Some of the most 

eminent botanists of the age have devoted their lives to the interpretation of this class of facts, and it has developed into an important department of natural science. Much, of course, remains to be done, particularly in this country, but when the plant deposits are as thoroughly 

explored as the animal deposits have been, stratigraphic geology will 

receive much valuable aid.

J In paleobotany two distinct lines of investigation have been followed, 

which may be called respectively the superficiar method and the structural meth&d.

I use the term superficial, not in the sense that the evidence obtained 

by it is untrustworthy, but because it takes cognizance of the external 

or superficial parts of plants. It deals with the form and nervation of 

leaves, the scars and striations on the stems, and the casts or impressions of stems, leaves, and fruits. On account of the many conditions 

necessary for the successful preservation of vegetable remains; it most 

frequently happens that they are capable of being studied only by this 

method. Its legitimate application is seen in the monographs of Heer, 

Ettingshausen, Unger, and Lesquereux.

The structural method, on the other hand, deals with what must be 

regarded as the most valuable of all evidence that derived from internal organization. Leaving out of view the superficial considerations, it 

concerns itself with a microscopical examination of the histological elements that enter into the composition of vegetable tissues. The vari11
12 FOSSIL WOOD AND LIGNITE. [BULL. 56.

ous tissue systems are dissected and carefully studied, the individual 

cells are measured and compared, and these, together with markings 

upon the cell walls and other like data, form a sure basis fpr the correct 

interpretation of the systematic position of plants. So valuable is this 

method that Prof. W. C. Williamson was led to say that " no determinations respecting fossil plants can have much absolute value save such 

as rest upon internal organization; that is the basis upon which all 

scientific recent botany rests, and no mere external appearances can 

outweigh the positive testimony of organization in fossil types." l

The interest attached to this class of investigations has been greatly 

enhanced of late, and it has been no doubt largely due to modern improvements in instruments and methods of research, but also to an increased appreciation of their value. Certain it is that the number of 

students in this field is being constantly augmented. In order to show 

that the growth of this department has been both natural and constant, 

I append a brief resume" of its progress from the time of its first mention in literature down to the close of the year 1886. In the preparation of this bibliographic review I have been greatly aided by the historic summaries of the literature given by Dr. Goppert in his Monographic der fossilen Coniferen,2 and by that of Prof. Lester F. Ward in 

his admirable " Sketch of Paleobotany." 3 The former of these is particularly, complete in the literature of the early or prescientific period, 

but closes, as indeed does the latter, with the year 1850. Consequently 

I have referred only briefly to the progress made prior to this date, but 

have aimed to make it as complete as space would permit for the time 

between 1850 and 1886. : 

It seems hardly probable, as Professor Ward has so pointedly suggested,4 that such common objects as pieces of petrified wood escaped 

all observation for the first twelve centuries of the Christian 'era ; but>

as the literature of that period contains no mention of them, we must 

suppose that public attention, at least, was not directed to the subject. 

That travelers and people engaged in agricultural pursuits must have 

observed them is more than probable, since fossil forests are now known 

to exist in northern Egypt, and plant beds have been found in Italy, 

Dalmatia, and other countries of the Eoman Empire. This fact is not, 

however, without its parallel in other departments of learning, for it hasbeen often shown that the ancients possessed a much more extensive 

and profound knowledge of nature than did any of the so-called learned 

men of the Middle Ages. 

Probably the earliest published account of petrified wood is that

1 On the organization of the fossil plants .of the coal measures. Roy. Soc. London, Phil.Trans., vol. 161 ? part n, 1871, p. 492.

2 Leiden, 1850. Pp. 71-166.

3 U. S. Geol. Surv., Fifth Ann. Rep., Washington, 1885, pp. 363-469.

4 Op. cit., p. 387.
KNOWLTON.] STUDY OF INTERNAL STRUCTURE. - 13

given by Albertus Magnus 1 in the thirteenth century, although the 

first mention of it has been attributed to Agricola (1494-1555). The 

writers of this period, however, were concerned more with the processes 

of fossilization than with the affinity of the objects described. Thus 

Agricola supposed petrification to take place by penetration of a succus 

lapidescens into the tissues of plants and animals, and Kentmann 2 

(1518-1568) described a process by which fossils could be produced artificially. Imperatus,3 Boyle,4 and Bromel 5 likewise wrote of the process 

of fossilization, and Cordus,6 Klein,7 and Matthiolus 8 in his letter to 

Bauhin also described specimens which came into their possession or 

expressed views concerning them.

The following writers, although principally interested in the origin 

of the fossils, actually described specimens. Agricola obtained what 

he supposed to be fossil ebony (Bbenholz) from Hildesheim. Gesner 9 

compared specimens which he obtained with the following living species : Fir (Elatites), alder (Glethrites), beech (Pkegites), and oak (Dryites). 

Under the name of Stelechites he also described a stem which showed 

rudiments of branches. Albinus 10 described a large birch from Krakewitz, in Bohemia.

The first book devoted entirely to the subject of fossil wood was 

published by Franciscus Stelluti, in Rome, in 1637, with the following 

title: "Trattato del legno fossile minerale nuovamente scoperto, nel 

quale brevemente si accenna la varia e mutabil natura di detto leguo 

rappresentato con alcune figure che mostrano il luogo dove nasce, la 

diversita delle onde che in esso sive dono e le sue cosi yarie e maravigliose forme." Stelluti recognized the resemblance between these and 

recent woods, but concluded that they differed so widely, in having 

neither roots nor branches, in burning with a clear flame and giving 

out more heat, and in other particulars, that it was impossible to suppose they had ever been living.

In the seventeenth century the writers and observers began to be 

more numerous. Thus we find Worman,11 Robert Hook, 12 Balbinus,13

1 Beati Alberti Magni de mineralibus Tractatus I, Caput vn,, Opera, Lugdnni, 1651, 

vol. 2, p. 216.

3 Nomeiiclatura rerum fossil., Tiguri, 1565. 

3 Hist, natur. Neapel, 1599; Venedig, 1672; Coin, 1695. 

4 Exerc. de util. et priest. Phil, natur.

8 Lith. Svec. spec.- 2. Cap. i, $ in.

6 Valer. Cordi adnot. in Pedacii Dioscovid., etc., aylva qua rerum fossilium in 

Germania, etc., 1651.

7 Balthasar Klein mentioned in GSppert's Monographic der fossilen Coniferen, 

p. 73. I have not been able to consult the book directly.

8 Matthioli epistol. edit. Bauhini, Lugd., 1564.

9 Gesneri de rerum fossilium, lapidum. et gemmarum maxime figuris et similitudiuibus liber, etc. Tiguri, 1565. 

10 Meissnischen Land- und Bergchronik im 22. Tit., S. 170. Dresden, 1589.

11 Museum. Wormian. Lugd. Batav., 1655.'

12 Micrographia, 1667.

l3 Bohuslav Balbinus. Miscell. hist, regni Bohem. Prag, 1679.
14 FOSSIL WOOD AND LIGNITE. [BULL. 56.

Abbe" de la Koque,1 Westphal,2 De la Hire,3 and John Morton 4 all mentioning or describing specimens. Edward Lhwyd 5 was the first to apply 

the term Lithoxylon to petrified wood. He seems also to have been the 

first to appreciate fully the value of paleontology to stratigraphy.

As the theories of fossilizatiou had gradually succeeded and replaced 

one another (the generatio aequivoca of Aristotle, the vis lapidifica of 

Avicenna in the tenth century, and the virtus formativa of Albertus 

Magnus in the thirteenth century), so were they supplanted in turn by 

the not less fanciful flood theory, which, strangely enough, seems to 

have been first propounded by Martin Luther.6 The idea that the 

plant and animal petrifactions brought to light were the remains of the 

Noachian deluge and had been tossed about and mingled by the angry 

waters did not meet with immediate acceptance, so widespread had become the other delusive hypotheses. But gradually it began to find 

followers, and we note that Gesner, Imperatus, Woodward, and Lhwyd 

gave it credence. Its chief exponent, however, was Johann Jacob 

Scheuch'zer, whose famous book, Herbarium Diluvianum, appeared in 

1709.

Scheuchzer violently attacked all the other theories and brought forward such a mass of seemingly overwhelming evidence in support of 

the flood theory that the world was fairly taken by storm, and many 

years passed before those even who saw the fallacy in it dared to stem 

public opinion and break away from it.

In 1723 an edition of his work was published at Leyden, in°which all 

the objects described in the edition of 1709 as well as in his Museum 

Diluviauum, were arranged according to the botanical system of Tournefort, which had appeared in the mean time. The fossil wood was 

arranged in the following manner:

CLASSIS XVIII. 

Arbores et frutices floribus apetalis.

This included only a leaf and a piece of wood of Fraxinus and the

wood of Buxus.

CLASSIS XIX.

 Arbores et frutices floribus apetalis amentaceis.

This class embraced specimens which he considered to belong to Ostrya, Quercus, Abies, Pinus, Betula, and several leaves, fruits, and cones 

of the same.

1 Zodiacum medico gallicum Gener., 1680. Part iv.

2 J. Gasp. Westphal. ephem. nat. curios, dec. n, an. vm, 1689.

3 Acade"mie Paris, M6m., 1692.

«Roy. Soc. London, Phi 1. Trans., 1706.

5 Evuardi Luidii Lithophylacii britannici ichuographia, sive lapidum aliorumque 

fossiliuin britannicorum singulari tigura insignium * * * distributio classica. 

Londini et Lipsise, 1699.

6 Griindliche und erbauliche Auslegung des ersten Buchs Mosis. Halle, 1739, vol. 

I, p. 176.
KNOWLTON.] STUDY OF INTEENAL STRUCTURE. 15

CLASSIS XXI. 

Arbores et frutices foliia rosaeceis.

Only a single specimen, "Frustum ligni tiliae petrifactum." 

PLANTS

Here were included the woods which could not be relegated to any 

of the other classes. This list was of course the larger, including more 

than one hundred and fifty miscellaneous examples, from various parts 

of the world, one even from the island of Antigua, in the West Indies. 

The term Lithoxylon was applied in a few cases (e. g., number 465, 

"Lithoxylon nigricans in saxo arenario duriosi ex Agro Altorffino/ 

but generally they were simply called if lignum fossile."

To enumerate the multitude of writers who made mention of fossil

wood, or described specimens of it, during the eighteenth century would

be to expand this chapter far beyond the limits assigned to it.1 We 

must confine our sketch from this time forth to those more important 

writers whose works mark distinct epochs in the' progress of paleodendrology. A few of the principal writers are Volkmann,2 Henkel,* 

Schroter,4 and Walch.5

The era of true science then may be said to have begun with the 

opening of the nineteenth century. Escaping from the influence of the 

superstitions and dogmas of the Dark Ages the keynote was struck, 

and from this time on the progress was constant and rapid. The true 

origin and nature of fossils were explained, and once on the right track 

the energy of investigators was directed to an interpretation of the 

paleontological facts, even in the most distant parts of the globe, and 

the result has been to furnish a pretty correct and comprehensive view 

of the faunas and floras of the different ages of the world's history.

In rapid succession were published the works of Voigt 6 (1807), who 

discussed the so-called Psarolithes, which he at first regarded as polyps ; 

Weppen 7 (1808), who described fossil wood from Europe, Siberia, and 

the East Indies; and Martin 8 (1809), who described fossil trunks 

from Great Britain. In 1814 Kieser published his valuable "M6- 

moire sur 1'organisation des plantes," in which, among other important

1 See H. R. Goppert. Monographic der fossilen Coniferen, pp. 81-86. 

a Georg Anton Volkmann. Silesia subterranea. Leipzig, 1720.

3 Flora saturnizans, 1755.

4 Lithographische Beschreibung von Ingolstadt und Dettwiz. Jena, 1768. 

6 Die Naturgeschichte der Versteinerungen zur ErlauterungderKnorrischen Sammlung, etc.* Nuruberg, 1768-1773.

6 Johann K. W. Voigt. Kurze mineralogische Bemerkungen. Leonhard's Taschenbuch fur Mineralogie, erster Jahrgang, pp. 120-124.

7 J. A. Weppen. Nachricht von einigen besonders merkwurdigen Versteinerungen 

und Fossilien seines Kabinets. Leonhard's Taschenbuch, vol. n, p. 176.

8 William Martin. Petrificata Derbiensia, or Figures and Descriptions of Petrifactions Collected in Derbyshire. Wigan, 1809.
16 FOSSIL WOOD AND LIGNITE. IBULL. 56.

facts, he first pointed out the characteristic structure of coniferous 

wood and correctly explained the nature of the concentric circles or 

bordered pits which are to be observed on the walls of the wood cells. 

These pits or pores had been observed by Malpighi l and others as 

«arly as 1685, but their exact nature had remained unexplained. An 

important work on the origin and nature of amber, by Dr. J. F. John, 

of Cologne, appeared in 1816. He supposed the amber to have been 

produced by a species of pine which he concluded had become extinct. 

About this time appeared several works by Jakob Noggerath 2 on certain upright trunks and other fossils of the Carboniferous age. In the 

two principal works of the year 1820, by Rhode 3 and Schiotheim,4 

only incidental mention is made of fossil wood, and then only from a 

consideration of external characteristics.

Passing rapidly over several minor English and American papers we 

come, in 1828, to the publication of what was unquestionably the most 

important work on fossil woods that had yet been published. This is 

the "Coinmentatio de Psarolithis, Ligni Fossilis Genere," published at 

Halle by Anton Sprengel. After reviewing carefully the literature of 

the subject and discussing the various theories of the nature of these 

organisms he established their undoubted vegetable character and 

described six species which he called Endogenites. The work, which 

is in Latin, is illustrated by a single plate. Says Professor Ward: 5

The year 1828 is without question the most eventful one in the history of paleobotany, since it saw the issue of Brongniart's Prodrome and the commencement of 

his Histoire des ve'ge'taux fossiles, which, taken together as they belong, form the 

solid basis upon which the science has since been erected.

The year 1830 was remarkable for the appearance of two papers by 

Henry T. M. Witham which gave evidence of the high and permanent 

place this author was to occupy in the annals of paleobotany. These 

papers, although short, treated of some of the peculiarities of structure 

to be observed in the plants of the Carboniferous of England. These 

observations were supplemented and extended in his " Observations 

on Fossil Vegetables, accompanied by Eepresentations of their Liternal 

Structure as seen through the Microscope," which appeared in the following year. In this volume, which was quarto in size, he discusses at 

length the peculiarities of structure which he was able to make out by 

the study of thin sections of the silicified specimens under the micro1 Marcelli Maphigii opera ommia. Lugd. Bat., 1687.

2 tJber aufrecht im Gebirgsgestein eingeschlossene fossile Baumstamme und andere 

Vegetabilien. Bonn, 1819.

Fortgesetzte Bemerkungen iiber fossile Baumstamme und andere Vegetabilien. 

Bonn, 1821. '

3 J. G. Ehode. Beitrage zur Pflajizenknnde der Vorwelt. Breslau, 1820.

4 Baron E. F. vou Schiotheim. Die Petrifactenkunde auf ihrem jetzigen Standpunkte. Gotha, 1820; Nachtrage, Gotha, 1822.

* Sketch of Paleobotany, in Fifth Annnual Report U. S. Geol. Survey, Washington, 

1885, p. 406.
KNOWLTON.] STUDY OF INTEENAL STRUCTURE. 17

scope. In the preparation of these thin sections he acknowledges his 

indebtedness to the kindness of Mr. William Nicol, of Edinburgh, who 

first brought the method to his attention. This new method, which is 

the one in use at the present time, worked a complete revolution in the 

study of petrified trunks, and from the appearance of this book the 

study of the internal structure of fossil plants may be said to date. 

These sections were made by first grinding a smooth surface on the 

specimen and cementing it with Canada balsam to a small piece of 

glass. As much as possible of the specimen was cut away, leaving 

a thin layer adhering to the glass, and this was ground down until it 

was thin enough to allow the light to pass through, when it was 

mounted permanently 'in Canada balsam. Witham examined in this 

way fossil coniferous, monocotyledonous, and dicotyledonous woods, 

which he compared with living forms, but did not venture to give names 

to them. This was left for his last and greatest work, which appeared 

in 1833. 1 In this work, after describing the localities in Great Britain 

from which his specimens were obtained and giving other information 

concerning them, he established four genera of fossil conifers, the first 

that had ever been described from considerations of internal organization alone. The new genera were: Peuce and Pitus, each with two 

species; Pinites, with five species; and Anabathra, with one species. 

A single species of Lepidodendron was also characterized. The organization of these plants was illustrated by sixteen plates, two of which 

were, however, devoted to living species, and considering the time at 

which these figures appeared they are remarkably good.

A work had been published a year previous to this time which had 

also done much to stimulate the study of internal structure. This was 

C. Beruhard Cotta's " Die. Dendrolitheii in Beziehung auf ihren inneren 

Bau," in which he attempted to " classify systematically and describe 

scientifically the various kinds of fossil wood that had been discovered." 

He studied the internal structure of specimens in his collection and described several new genera and species. While the illustrations in his 

book are inferior to Witham's, they are nevertheless sufficiently characteristic to be readily recognized.

Besides several shorter papers that appeared about this time by Pattinson,2 Parkinson,3 and others, the year 1831 saw the beginning of 

Lindley and Button's great work, the " Fossil Flora of Great Britain." 

This work, which was not completed until 1837, was concerned principally with the superficial phase of the fossil flora, but contained never-

'The Internal Structure of Fossil Vegetables found in the Carboniferous and Oolite 

Deposits of Great Britain, Described and Illustrated. Edinburgh, 1833.

2 H. L. Pattinson. On the Fossil Trees found in Jefferies Rake Vein at Derwent 

Lead Mine in the County of Durham. Phil. Mag. and Annals, vol. 7, London, 1830, 

pp. 185-189.

3 James Parkinson. Outlines of Oryctology. An Introduction to the study of Fossil Organic Remains. London, 1830. Fossil wood, pp. 21-33. 

Bull. 56 2
18 FOSSIL WOOD AND LIGNITE. [BULL. 56.

theless illustrations arid remarks on three of the species of Piiiites (P. 

Brandlingi, P. Withami, and P. medullaris) mentioned by Witham.

In 1833 William ^Nicol published his valuable " Observations on the 

Structure of Recent and Fossil Coniferse," l which was the first systematic comparison of internal structure instituted between living and fossil species. He examined quite an extensive series of living conifers, 

which he illustrated in six plates accompanying the article, and pointed 

out some facts that must be observed in the study of fossil forms. He 

refers to the method of preparing thin sections, which was credited to 

him by Witham as his invention, and says that it was not original with 

himself, but derived from a Mr. Sanderson, a lapidary of Edinburgh. 

In the following year he published a second article,2 in which he decribed fossil dicotyledonous wood from the island of Mull with conifers 

and dicotyledons from Egypt and Nubia, and conifers from the Cape of 

Good Hope. He did not, however, attempt to give names to anything 

examined from these localities.

We pass hastily over the period from 1835 to 1839, during which 

papers of some interest in this department appeared by Bronn, 3 Gazlay,4 and others, and come to the publication of Brongniart's splendid 

memoir on Sigillaria elegans.5 Having obtained from the environs of 

Autun, Aix-la-Ohapelle, and Werdeu some perfectly silicified fragments 

which showed on the exterior the leaf scars characteristic of this 

species, Brongniart was enabled to examine for the first time the internal organization of this interesting group of plants. After describing 

carefully his specimens of Sigillaria elegans he compared them with all 

the other Carboniferous species of which the structure was known. 

These he divided into three, groups, according to the distribution of 

the vascular elements. As Sigillaria elegans showed undoubted evidence of exogenous growth it was placed by Brongniart among the 

Gymnosperms, a position which was further insisted upon in 1849 in 

his " Ta.bleau des genres de ve"ge"taux fossiles." Although the conclusion 

as to the systematic position of this species has since been shown by 

Williamson, Zeiller, and others to be incorrect, the publication of this 

memoir was a long step towards a solution of some of the most difficult 

problems of the relations between Cryptogams and Phseuogams.

Although Witham, Nicol, and others had described the structure of 

fossil dicotyledonous woods, no one had ventured to name genera or

1 Edinb. New Phil. Jour., vol. 16, 1833-'34, pp. 137-158, pi. u-iv, pp. 310-314, pi. v.

2 On the structure of some fossil woods found in the Island of Mull, Northern Africa, and on the Karoo Ground to the northeast of the Cape of Good Hope. Edinb. 

New Phil. Jour., vol. 18, l834-'35, pp. 335-338.

3 Heiurich Georg Bro"uu. Lethtea geognost'ica'. Stuttgart, 1835-'38.

4 Kev. Sayrs Gazlay. Notices of Fossil Wood in Ohio. Am. Jour. Sci., vol.25, 

1834, pp. 104-107.

6 Observations sur la structure inte"rieure du Sigillaria elegans comparte a celle 

des Lepidodendron et des Stigmariaet a celle des ve"ge"taux vivante. Mus. Hist. Nat., 

Paris, Archives, 1839, pp. 405-461, pis. xxv, xxxv.
KKOWLTON.J STUDY OF INTERNAL STRUCTURE. 19

species until Goppert, 1 ia 1839, characterized his Klcedenia quercoides,

a genus which, is now included under Querciniura of linger.

. Several short papers appeared in 1841 by linger,2 Goppert,3 and

others.

During the year 1842 Kutorga, in a short paper on the paleontology 

of Russia,4 described three new species of fossil wood, two of which 

are from the JIupfersandsteine of Perm, the other from the Kreidegebirge of Don. They were Pence biarmica, Pence tanaitica, and Pinites 

biarmlcus. Goppert in this year contributed a paper 5 on the flora of 

the iron sands of Aachen, in which he made valuable suggestions in regard to the method of studying fossil wood. Recognizing the fact that 

little could be accomplished in the study of fossil forms without a 

thorough knowledge of the internal structure of living species, he made 

a very careful examination of more than one hundred living species, of 

conifers. These he arranged iu four groups, viz: the Piuus, Araucaria,

Taxus, and Ephedra forms, and briefly characterized each.

For the fossil Coniferse of Aachen he adopted Withani's name Pinites, 

and described a single new species, Pinites aquisgranensis.

Another new species of Pinites (P. gypsaceus) was described in the 

Flora der Gypsforrnatiou iu Oberschlesieu.6

Goppert also published a paper7 011 the Cycadacese, in which, after 

reviewing what he had before written on the subject, he monographed 

the order. Of the seventy-eight species known at that time, nine were 

characterized from the trunks, sixty-five from the fronds, and four from 

the fruit.

The year 1845 was remarkable for the production of three great 

works, besides numerous smaller papers. These were Corda's "Beitrage zur Flora der Vorwelt," 8 Goppert's Amber-Flora,9 and Unger's

1 " Bomerkungen iiber die als Geschiebe iui nordlichen Deutschlaiid vorkomuienden 

versteinerten Holzer." Neues Jahrb., 1839, pp. 518-521, pi. vm B.

3 Franz Unger. . Ueber die versteiuerten Holzer des National-Museums zu Lintz. 

Warte au der Donau, August, 1841, pp. 497-499.

3 Taxites scalar! form is, eiuo neue Art fossileu Holzer. Karst. Archiv. fUr Mineral., 

etc., vol. 15, 1841, p. 727, plate xvn, figs. 1-7.

4 Dr. S. Kutorga. Beitrag zur Palaeontologie Russlands. Russ. kais. miuerajL. 

Gesell., St. Petersburg., Verhandl., 1842, pp. 1-34, plates i-vi.

6 Fossile Pnanzeureste des Eiseusands von Aachen, als z welter Beitrag zur Flora der 

Tertiargebilde. Acad.Leop. car. Nat. cur. Acta, vol. 19,1842, pp. 137-160, plate LIV.

6 Ueber die fossile Flora der Gypsforniatiou zu Dirschel in Oberschlesien, als dritter Beitrag zur Fl. d. Tertiargebilde. Acad. Leop.. Car. nat. cur. Acta, vol. 19, 

1842, pp. 369-378, plates LXVI-LXVII.

'Ueber die fossilen Cykadeen iiberhaupt, mit Riicksicht auf die in Sclilesien vorkommenden Arten. Schles. Gesell. f. vater. Kult., Uebersicht, 1842, pp. 114-142.

8 August Joseph. Corda. Beitriige zur Flora der Vorwelt. Prag, 1845, pp. 1-123, 

plates I-LX.

9 G. C. Bereudt. Die im Bernstein befmdlichen organischen Reste der Vorwelt. 

Vol. I. Berlin, 1845. i. Abtheilung: Der Bernstein and die iu ihm ben'ndlichen 

Pflauzenreste der Vorwelt (by Dr. Goppert). k .
20 FOSSIL WOOD AND LIGNITE. IBULL. 66.

Synopsis plantarum fossilium. 1 Lack of space prevents a satisfactory 

analysis of these works, and I will simply say that the first in the list, 

by Corda, is a magnificent folio, illustrated by sixty plates, nearly all 

of which are devoted, to internal structure. Goppert's Amber-Flora 

was a complete summary of the known facts relating to the origin of 

amber, and also an enumeration of all the plants detected in it. The 

amber he thinks was produced almost entirely by a single species of 

pine, which he called Pinites succinifer. Unger's Synopsis enumerated 

1,648 species of plants, the total number known at that time.

In 1847 appeared Unger's "Chloris Protogsea," 2 another magnificent 

work, containing characterizations of a considerable number of new 

genera of Dicotyledons. The genera that appear for the first time are 

Ulminiurn, Fegonium, Quercinium, Betulinium, Acerinium, and Plataniuium, named for their resemblance to wood of Ulmus, Fagus, etc. 

Many fine figures illustrate the work.

Equally important was Eudlicher's "Synopsis Coniferarum," 3 which 

also appeared in 1847. Of the 177 species mentioned nearly 60 are 

characterized from internal structure.

This hasty review closes the period from the ofigin of definite ideas 

concerning .petrifactions to the beginning of the year 1850, which is 

remarkable for the production of two of the most important works. 

These were "Monographie der fossilen Coniferen," 4 by Goppert, and 

"Genera et species plantarum fossilium," 5 by Unger.

Goppert's work was a most elaborate essay, filling 359 quarto pages 

and illustrated by 58 plates, more than half of which is devoted to 

internal structure. The first 67 pages of the work describe the living 

conifers, which he considers under the following heads: f. Historical 

review of our knowledge of the Ooniferae. II. Geographical distribution. III. Organography and anatomy. This last part is, for the 

student of internal structure, perhaps the most important, as here are 

passe'd in review all the terms used in the description of the external 

and internal parts, with special emphasis of those characters which are 

found to be of the most importance in the diagnosis of genera and 

species.

The part devoted to the fossil Coniferse is likewise divided into 

several subdivisions. The first-of these is a historic review of the 

study of fossil plants, particularly the conifers, from the first crude 

speculations of the ancients through the formative period of the Middle Ages to the scientific.period of our own times. This part more

'Lipsise, 1845.

2 Chloris Protogsea. Beitrjige zur Flora der Vorwelfc. Leipzig, 1847.

3 Stephen Endlicher. Synopsis coniferarum. Sangalli, 1847.

4 Monographie der fossilen Coniferen. Natuurkundige Verhaudelingen van de Hollandsche Maatschappij der Wetenschappen te Haarlem. Tweede Verzameling, 6*> 

Deel Leiden, 1850.

6 Genera et species plantarum fossilium. Vindobonae, 1850.
KNOWLTON.I STUDY OF INTERNAL STRUCTURE. 21

than any other shows the scholarly attainments of the illustrious author. 

He seems to have read everything that had even the most remote bearing upon the subject. '

In the systematic part, which occupies pages 169-248, he follows the 

divisions of the fossil forms into four groups as proposed by himself 

in 1842. In the Cupressinese he established the genus Cupressinoxylon 

and described under it 15 species. Of the Abietiuea3 he described 38 

species of Piuites, 6 of which were new; il species of Araucarites; 2 of 

Pissadendron and 1 of Protopitys. Under the Taxiueae he enumerates 

4 species of Taxites and 1 each of Physematopitys and Spiropitys. 

Of the Guetaceai none are characterized from internal structure.

In the last part are enumerated all the localities where fossil wood, 

beds of coal, etc., occur, with a statement of the geological horizon to 

which each belongs.

A careful analysis of Unger's "Genera et species" can.not be attempted. It is sufficient to say that it contains descriptions of 2,421 

species of pfants, a great advance in knowledge over anything that 

had previously appeared.

Two interesting papers on the structure of palms were published by 

C. G. Steuzel 1 during the year.

For the next few years, while much material was published that was 

of general interest in paleobotany, nothing of special importance came 

out relating to the internal organization of plants. Most of the papers 

were systematic descriptions of the flora of various localities and contain only incidental mention of fossil wood. Of this character were 

the papers of Weber,2 Goppert,3 Massalongo,4 and Mercklin.5

Goppert's "Beitriige zur Tertiarflora Schlesien's" G was of more importance, as it contains descriptions of several species of Cupressinoxylon, 

Pinites, Physematopitys, Taxites, and Spiropitys.

One of the first contributions to pur knowledge of American deposits 

of lignite was that by Edward Hitchcock 7 on the brown coal deposit 

in Braudon, Yt. No attempt at identification of species from study of 

structure was made except that a pine cone in connection with "pine 

lignite" is mentioned. Many figures of dicotyledonous fruits, which

l De trunco palmarum fossilium. Inaug. cliss. Vratislavise, 1850, pp. 1-18, plates I, 

n. Zwei Beitriige zur Keiiutniss rler fossileu Palinen. Acad. Leop.-Carol. Nova 

Acta, vol. 22, Breslau, 1H50, pp. 4G7-508, plates 51-53.

2 C. Otto Weber. Die Tertiarflora der niederrheinischen Braunkohlenformation. 

Palaeontograpliica, vol. 2, Cassel, 1852, pp. 115-236, plates xvm-xxv.

J Fossile Flora des Uebergaugsgebirges. Acad. Leop.-Car. nat. cur. Nova Acta, 

. vol? 22, Supplement, 1852, pp. 1-299, tab. I-XLIV.

4 Synopsis palmarum fossilium. Natur.-Wiss. Verein Lotos, vol.2,1852,pp. 193-208.

6 C. vou Mercklin. Ueber fossiles Holz und'BemsteininBrauukohleaus Grishiginsk. 

Acad. Imp. So. St.-Pe"tersbourg. Bull. Classe Phys. Math., vol.11, pp. 81-93, pi. I.

6 Palaeontographica, vol. 2, Cassel, 1852, pp. 257-282, plates xxxni-xxxvm.

7 Description of a brown coal deposit in Brandou, Vermont, with an attempt to 

determine the geological age of the principal hematite ore beds in the United States. 

Am. Jonr. Sc., 2fl ser., vol. 15, 185 pp. 95-104.
22 FOSSIL WOOD AND LIGNITE. IBULL. 56.

were afterwards identified and named by Lesquereux,1 accompany the 

article

The first American investigations of the internal organization of 

 fossil wood seem to have been made in 1854 by Dr. (now Sir) J. W. 

Dawsou, who mentions 2 specimens from Prince Edward Island which 

exhibited on the wood cells the hexagonal disks characteristic of the 

Araucarian type. The specimens are described as beiug perfectly silicified trunks of trees, in some cases three feet in diameter; they are prostrate and slightly flattened. These were subsequently described by 

Dawson as species of Dadoxylou, but no identification is made in this 

paper.

In the same year, but of less importance, was a note 3 by Dr. A. T. 

King on fossil trees in the coal rocks of Pennsylvania.

The year 1854 was particularly remarkable for the European activity 

manifested. C. G. Stenzel,in his " Staarsteine," 4 monographed the genus 

Psaronius, enumerating 18 species, and gave much valuable information regarding the structure and synonomy. The six plates all illustrate the internal structure. Goppert, in his Tertiary Flora of Java, 5 

described the deposit of fossil wood of that country and established 

three new genera (Junghuhuites, Bradsea, and Miquelites), each with a 

single species. 

Unger, in his Flora of Gleichenberg,6 described several conifers 

and three species of dicotyledons, and Balfour 7 wrote of the vegetable 

structure detected in the coal of Fordel, a subject which had since the 

time of Witham attracted great attention.

The most important publication during 1855 was that of Schmid and 

Schleiden, "Ueber die Natur der Kieselholzer."^ It is divided into 

two parts: the first treats of the average chemical composition of 

silicified wood and the second is a systematic description of the fossil 

wood in the Grand Ducal Museum of Jena. Twelve species are cnumer1 Am. Jour. Sc., 2d ser., vol. 32,1881, pp. 355-363. Also see Hitchcock's Geology of 

Vermont, vol. 2, pp. 712-718.

2 0u fossil coniferous wood from Prince Edward Island. Acad. Sc. Phi]., Proc., 

vol. 7, 1854, pp. 62-64.

3 Description of fossil trees in the coal rocks near Greensbnrgh, Westmoreland 

County, Pennsylvania. Acad. Sc., Phil., Proc., vol. 7, 1854, pp. 64-65.

4 Ueber die Staarsteine. Acad. Leop. Car. Nova Acta, vol. 24, Jena, 1854, pp. 

753-896, plates 34-40.

5 Die Tertilirflora auf der Insel Java, uach den Eutdeckuugen des Herrn Fr. Junghuhn beschriebeu u. erortert in ihrem Verhiiltnisse zur Gesammtflora der Tertiiirperiode. 's Gravenhage, 1854.

6 Die fossile Flora vou Gleichenberg. K. Acad. wiss. Weiu, Denkschriften, vol. 7, 

1854, pp. 157-184, pi. i-vin.

7 J. H. Balfour. On certain vegetable organisms found in the coal of Fordel. Roy. 

Soc. Ediub., Trans., vol. 21, 1854, pp. 187-193, pi. n.

8 E. E. Schmid und M. J. Schleiden. Ueber die Natur der Kieselholzer. Jena, 1855, 

pp. 1-42, plates i-m.
KNOWLTON.] STUDY OF INTERNAL STRUCTURE. 23

ated, of which four are new conifers and four new dicotyledons, and 

three new genera established, each with a single species.

In the next year several notices appeared by American authors. One 

by George C. Schaeffer described 1 the structure of two specimens of 

wood from the Colorado Desert. The specimens were very well preserved and are undoubtedly dicotyledonous, as is also the specimen 

from Posuncula Eiver described by Prof. W. J. Bailey.2 No names 

are given in either case, but the specimens from Colorado are compared 

with figures of dicotyledons from Antigua given by Witham in his "Internal Structure of Fossil Vegetables."

Dawson also described and figured 3 the internal structure of wood 

from-the Devonian of Gaspe, Canada East. The specimens, he says, 

were collected by Sir W. E. Logau in 1844, and placed in the collection 

of the Canadian Geological Survey. No attempt is made by Dawson 

to name these fossils, but they were without doubt coniferous.

Eichter audUnger contributed a valuable paper," "Beitrag zur Palfeontologie des Thiiringer Waldes," 4 in which the structure of Calamopteris, Calamopitys, Stigmaria, Lepidoderidron, Cladoxylon, Aporoxylon, 

etc., is illustrated.

From 1856 to 1860 many interesting papers were published, of which, 

limited space will allow only the briefest mention. Goldenberg 5 monographed the Selagineae a/id the Sigillariese; Goppert 6 describes briefly 

the fossil-forests discovered by Mollhausen in New Mexico and named 

a single new species (Araucarites Mcellhausianus). Unger also contributed two valuable articles. In one of these he describes 7 the petrified forests near Cairo and in other parts of Egypt. Several new 

species are characterized, among them Nicolia JEgyptiaca, which was 

named in honor of William Nicol, who will be remembered as the contemporary of Witham. The other paper, " Ueber fossile Pflanzen des 

Siisswasser-Kalkes und Quartzes," 8 describes and figures the internal

1 Description of the structure of the fossil wood from the Colorado Desert. U. S. 

Pac. R. R. Rep., vol. 5, 1856, pp. 338,339, plate xu, figs. 3, 4.

2 Letter from Prof. J. W. Bailey, describing the structure of the fossil plant from 

Posuncula River. U. S. Pac. R. R. Rep., vol. 5, 1856. p. 337, pi. xn, tigs. 1, 2.

3 J. W. Dawson. Remarks on a specimen of fossil wood from the Devonian rocks 

(Gasp6 sandstones) of Gaspd, Canada East. Am. Assoc. Adv. Sc. Proc., vol. 10, 1856, 

pp. 174-176, figs. 1-4.

4 R. Richter und F. Uuger. K. Acacl. Wiss. Wieu, Denkschr., vol. 11, 1856, pp. 

1-100, plates i-xui.

B Friedrich Goldenberg. Flora SartepontauaFossilis. DiePflauzeuversteinerungen 

des Steinkohlengebirges von Saarbriickeu. Saarbriicken, 1855-'57.

6 Ueber die von Mollhausen mitgebrachten Fragmente des Holzes aus dem versteinerten Walde. In Mollhausen's Tagebuch eiuer Reise vom Mississippi nach den 

Ktisten der Siidsee. Leipzig, 1858, p. 492.

7 Der versteinerte Wald bei Cairo und einige andere Lager verkieselten Holzes in 

Agypten. Sitz. K. Acacl. Wiss. Wi&u, math.-uat. hist. Kl. vol. 33, 1858, pp. 209-233, 

plates i-in.

8 F. Uuger. K. Acad. Wiss. Wien, Denkschr., vol. 14, 1858, pp. 1-38, plates i-v.
24 FOSSIL WOOD AND LIGNITE. (BULL. 56.

structure of species of Araiido, Nymphsea, Thuioxylon, Betulinium, 

Klippsteiuia, Peuce, and Hauera. The species are all European, with 

the exception of Hauera Americana, which is from Papautla, Mexico.

In 1859 Dawsou again returned to the study of the plants of the 

Peninsula of Gasp6, Lower Canada, and for the first time made positive determinations of them. 1 He visited Grasp<§ in person and collected an extensive series of specimens, upon which he founded several 

new genera and species. The first of these is Psilophyton, a genus of 

lycopodiaceous plants, "which is characterized by slender, bifurcating, 

ridged ^sterns, proceeding from a horizontal rhizoma, which sends forth 

numerous rootlets." The internal structure had in most cases disappeared ; yet it could be traced in a few instances. It is described as 

consisting "of a slender axis of scalariform vessels, surrounded by a 

space now occupied by calcspar, but showing in parts the remains of a 

loose, cellular tissue. Externally to this is a cylinder of well preserved, 

elongated, woody ce'lls, without distinguishable pores, but with traces 

of very delicate spiral fibers." Two species are established.

Prototaxites is described as a new genus of conifers in the following 

manner: "Woody trunks, with concentric rings of growth and medullary rays. Cells of pleurenchyma scarcely in regular series, thick 

walled and cylindrical, with a double row of spiral fibers. Disk 

structure indistinct." Coming, as this plant floes, from the Devonian, 

it was regarded as one of the oldest forms of coniferous 'structure 

known, and yet it was highly differentiated even then, as is shown by 

the fact that its nearest; living representatives were thought by Dawson 

to be Taxus and Torreya. Other remains of tissues, doubtfully referred 

to Unger's Aporoxylou, may represent a still more primitive phase.

In the same year was published a further contribution by the same 

author on the vegetable structures in coal,2 the observations applying 

to the bituminous coal of Nova Scotia. He divides the coal into two 

classes: mineral charcoal and compact coal. In the mineral charcoal 

he detected both cryptogamous and gyniuosperinpus tissue. Iri the 

former were abundant remains of scalariform tissues belonging apparently to Lepidodendron, Ulodendron, Stigmaria, and even Sigiilaria. 

Of the gymnospermous tissues the identifications were less x positive, 

although they were unquestionably coniferous and probably belonged 

to the Araucarian type.

Of the structure observed in compact coal comparatively little could 

be satisfactorily made out, although fragments apparently of both 

cryptogams and conifers were detected in exceptionally well-preserved 

specimens.

'On Fossil plants from Devonian Kocks of Canada. Quart. Jour. Geol. Soc., 

vol. 15, 1859, pp. 477-478, figs. 1-G; also, Can. Nat. and Geol., vol. 5, 186U, pp. 1 14, 

tigs. 1-G.

2 0n the Vegetable Structures in Coal. Quart. Jour. Geol. Soc., London, vol. 15, 

1859, pp. 626-641, pi. xvu.
KNOWLTOS.J STUDY OF INTERNAL STRUCTURE. 25

In 1861 there appeared an important work by Dr. F. Hildebraud, 1 in 

which he discusses in a very exhaustive manner the distribution of both 

living and fossil Coniferoe. The geological, as well as the geographical, 

distribution of the fossil species was given and has been of great aid to 

the student of stratigraphy. Several maps and tables illustrate the 

paper.

Curious remains of plant structure, identified as Araucarites Schrollianus, were detected by Bornemann2 in quartz crystals.

The study of American material was carried on with great vigor by 

Dawson, who contributed numerous articles touching more or less upon 

the internal organization of the plants of Devonian and Carboniferous 

ages in Canada, Nova Scotia, and other regions. One, in 1861, "On the 

Pre-Carboniferous flora of New Brunswick, Maine, and Eastern Canada,3 

contains descriptions of species of Dadoxylon, Prototaxites, Sternbergia, Aporoxylon, etc., but a more elaborate aiid systematic paper

than he had published up to this time was that on the " Flora of the 

Devonian Period in Northeastern America," 4 which appeared in 1862. 

In this he first discusses the localities in New York, Maine, Canada, 

and New Brunswick from which Devonian fossils have been obtained. 

In the systematic portion which follows, no less than 69 species belonging to 32 genera are described, of which number 36 species are regarded 

as new. Most of these are; of course, described from stem, leaf, or fruit 

impressions; but a few are characterized from internal structure, among 

them Syriugoxylon, a new dicotyledonous genus. The single species 

known is from the upper part of the Hamilton Group, on Lake Erie. 

A new Dadoxylon, also from the same group, in Ontario County, New 

York, is described.

Among some of the shorter papers of this time m'ay be mentioned one 

by Schirnper,5 in which Dadoxylon vogesiacum is described as new, and 

one by Unger on some fossil plants from New Zealand.6 Two species of 

wood, Podocarpium dacrydioides and Nicolia zelandica, are mentioned by 

Unger. The first species of Nicolia it will be remembered was from the 

Egyptian Desert, and the occurrence of another species in New Zealand 

is of interest.

Goppert's "Flora of the Permian Formation," 7 which appeared at 

Cassel in 1864-'65, was another of the many valuable works produced by

1 Die Verbreituug der Couifereii in cler Jetztzeit und iu dea fraheren geologischeu 

Perioden. Bonn, 1861, 8°.

. 3 J. G. Bometuaan. Ueber Pflanzenreste iu Quarzkrystallen. Deutsch. geol. 

Gesell., Zeitsclir.,vol. 13, Berlin, 1861, pp. 675-681, plate xvi.

3 Can. Nat. and Geol., vol. 6,1861, pp. 161-180.

4 Quart. Jour. Geol. Soc.,vol. 18,1862, pp. 296-330, pi. xn-xvn. 

8 Le Terrain de Transition des Vosges. Par tie Paldoutologique, par Wm. Ph. Schimper. Strasbourg, 1862, p. 342, plate xxx.

6 Fossile Pflanzen aus Neu-Seelaud. Iu Hochstetter's Geologie von Neu-Seeland, 

Wien, 1864, pp. 1-13, plates i-v.

7 Die fossile Flora der permischeu Formation. Cassel, 1864-'65.
26 FOSSIL WOOD AND LIGNITE. [HULL. 56.

this author. It contains 316 pages and 64 plates, not a few of the latter 

being devoted to internal structure. It is a systematic work, and describes and discusses with great fullness the 272 species that had at that 

time been collected from the Permian, Without attempting an exhaustive analysis, an idea of its magnitude and of the value'to the student of the internal structure of fossil plants may be obtained by noting 

the number of species described from internal structure. There are 43 

species of fern stems and rhizomes, of which number 25 belong to the 

genus Psaronius alone.0 The Cycadacese are represented by three 

species of Zamites, two species of Medullosa, and one species each of 

Steuzelia, Myelopitys, and Colpoxylon. The Conifers are represented 

by 16 species of Araucarites and a single species of Pinites. The work 

closes with a discussion of the origin and distribution of the Permian 

flora.

Another work of great value, also published in 1864, was the microscopical examination made by Kraus of the structure of living and fossil Conifer^. 1 Wishing to ascertain, for use in the elucidation of fossil forms, what marks were of the most diagnostic value, he examined 

upwards of one hundred living species and obtained results which have 

been generally accepted. Without giving a full exposition an example 

will suffice. He investigated the width of the annual ring and found 

that it had no value as a distinctive mark, 'as it varied in different parts 

of the same individual and also widely from year to year, this latter variation being the result of changes in temperature and in moisture. In 

composition the ring consists of an inner, a middle, and an outer layer. 

The inner layer, or spring wood, consists of thin-walled, mostly foursided cells, with bordered pits only on the radial walls; the middle 

ayer, of thicker, mostly polygonal, cells, which have a decreasing radial 

diameter 5 the outer layer, or fall wood, is of thick-walled, compressed 

cells, with bordered pits ou the tangential as well as on the radial walls, 

The predominance of certain layers may help to distinguish stein from 

root wood. Thus in the stem the cells of the inner layer predominate j 

in the root, the cells of the middle layer.

In similar manner were taken up the wood cells, resin cells and ducts, 

and medullary rays, and more or less valuable characters were drawn 

from them.

Equally useful observations were made on the fossil forms studied 

and several species new to science were diagnosed.

In 1863 Dawsou described four new species of Dadoxylon from the 

coal formation in Itfova Scotia.2

1 Gregor Kraus. " Mikroskopische Untersuchungen iiber den Ban lebender und 

vorweltlicher Nadelholzer." Wiirzburger naturwiss. Zeitschr., vol. 5, 1864, pp. 144- 

200, plate V. u

z Synopsis of the Flora of-the Carboniferous Period in Nova Scotia. Montreal, 

1864, pp. 1-27. Reprint from Can. Nat., 1863, vol. 8. t
KNOWLTON.] STUDY OF INTERNAL STRUCTURE. 27

In the same year E. W. Binney published 1 a continuation of his observations on the structure of the coal plants of England. The specimens, eight in namber, upon which these observations were made, were 

from the lower division of the coal measures of Lancashire and Yorkshire, and were embedded in calcareous nodules which occur in seams 

of coal. They were very perfectly preserved and yielded valuable results; but, as the author says in the conclusion, the memoir " was intended to be more of a descriptive character than an attempt to trace 

the analogy of the plants." They are, however, referred to Diploxyloq 

and Sigillaria.

Several short but valuable contributions appeared about this time 

from the pens of Unger,2 Kraus, and others.

In one of these papers Unger reports the occurrence of Nicolia 

2Egyptiaca from the highlands of Abyssinia. In another 3 he characterizes two new genera of dicotyledons (Constantiuium and Tchihatcheffites) from Thrace in Asia Minor.

Kraus, in his paper "Ueber einige bayerische Tertiarholzer," 4 enumerates several well-known conifers and a new species of birch (Betula 

lignitum^ and in his "Zur Kenntniss der Araucarien des Rothliegenden und der Steinkohlenformation," 5 he combined and characterized 

several species of Araucarites.

The year 1868 saw the completion of Eichwald's great work on the 

paleontology of Russia.6 This work, which was begun as early as 

1851), consists of two parts, Ancienue Pe"riode and Pe"riode Moyenne, 

each accompanied by a folio atlas of plates, many of which are devoted 

to internal structure. It is impossible to give even an approximate 

analysis of the work, and we can simply say that it placed at the disposal of savants all the facts then known of the paleontology, animal 

as well as vegetable, of this vast empire.

This year was noteworthy also for the production of important papers 

by Cramer, Carruthers, Biuney, Hooker, and others.

The"Fossile Holzer der arctischen Zone," 7 by Cramer, deserves spe. 

ciai mention. He describes and figures wood from. Greenland, Banks 

Land, and Spitzbergen, which, with one exception, was found to be all 

coniferous. From Greenland came two species of Oupressinoxylon (0.

1 A description of some fossil plants, showing structure, found in the Lower Coal 

seams of Lancashire and Yorkshire. Roy. Soc. London, Phil. Trans., 1865, pp. 579-604, 

pis. xxx-xxxv.

2 Notiz iiber fossile Holzer aus Abyssinien. Wien, 1866, pp. 289-297, plate I.

3 Flore tertiaire moyenne. In Tchihatcheff's Asie Miueure. Paris, 1866-'69, 4° partie, pp. -319-325, pi. xvn, figs- 1-4.

4 Wiirzburger naturwiss. Zeit., vol. 6, 1866-'67, pp.- 45-48.

"Op. cit., 'pp. 70-73.

6 £douard D'Eichwald. Lethsea Rossica, on Pale"ontologie de la Russie. Stuttgart, 1853-'68.

7 Cramer. In Flora fossilis arctica. Oswald Heer. Vol.1. Zurich, 1868, pp. 167- 

180, plates XXXIV-XLIII
28 FOSSIL WOOD AND LIGNITE. IBULL, 56.

Breverni Merekl. and C. ueranicum Gopp.); from Banks Land, a single 

species of Pin us (P. MacClurii Heer), three species of Cupressinoxylon (G. pulchrum Crarner, G. dubium Crainer, and C. polyommatum 

Cramer), and the now well known Betula MacGlintockli; from Spitzbergeu came three species, all new,°of Pinites (P. latiporosus, P. panciporosus, and P. cavernosus).

Carruthers's paper on the Oycadean stems of Britain1 was a valuable contribution to our knowledge of this poorly understood family. 

So, also, were Hooker's papers on the structure of Stigmaria* and on 

*the structure and affinities of some Lepidostrobi.3

Binney issued in this year the £rst part of his "Observations on the 

Structure of Fossil Plants found in the Carboniferous Strata," a consideration of which is deferred.

The most systematic contribution to our knowledge of^he fossil Coniferae published since Goppert's Monographie was that of Dr. Kraus, 

in Schimper's "Traite" de Pale"ontologie Ve'ge'tale." 4 Ever since the publication of Goppert's work, u De Coniterarum structura auatomica," in 

1841, the opinion had been growing among students that the genera 

must be regarded as comprehensive; that is, that a genus established 

upon fossil remains may include what might be regarded as several 

distinct genera, provided they were living and in possession of other 

organs which are of taxonomic value. With this point settled, Kraus 

divided the Coniferse into the five following types, which, it will be observed is one more than Goppert admitted:

I. Type of Cupressiueue (Cupressoxylou), comprising all the CupressinesB, the 

Podocarpese, and a part of the Taxeae.

II. Type of the Abietinese (Cedroxylon), including the genera Abies, Picea, Larix, 

and Cedrua.

III. Type of the Pinacese (Pityoxylon), which includes the genus Pinus and its 

snbgenera

IV. Type of the Araucariese (Araucarioxylon), which will include Araucaria, 

Agathis, etc.

V. Type of the Taxese (Taxoxylon), comprising all the genera not included under 

CupreSsoxyloh.

Aporoxylon Unger is still retained as a genus iucertse sedis.

To these six generic types all the other names in use were reduced as 

synonyms. Thus Cupressoxylon Kraus included Thuioxylon of .linger 

and Endlicher and Physematopitys of Goppert; Araucaroxylou Kraus 

was made to include Araucarites Gopp., Pissadendron Eudl., and PaIseoxylon Brongn. Other changes it is unnecessary to mention.

1 William Carruthers. On Fossil Cycadean Stems from the Secondary Rocks of 

Britain. Linn. Soc. Loud., Traus., vol. 26, 1868, pp. 675-708, pis. LIV-LXUI.

2 On some peculiarities in the structure of Stiginaria. -Geol. Surv., Gt. Brit. Mem., 

vol. 2, pt. 2, 1848, pp. 431-439, pis. I, n.

3 Remarks on the Structure and Affiuinities of some Lepidostrobi. Op. cit., pp. 

440-456, figs. 1-5 in text.

4 Bois fossiles des coniferes. lu Traite" de pale"ontologie Ve'ge'tale, W. P. Schiinper, 

vol. 2, Paris, 1870-72, pp. 363-385, Atlas, pi. LXXIX. '
KNOWLTON.I . STUDY OF INTERNAL STEUCTURE. 29

This systematic arrangement was followed by a detailed enumeration 

without description of all the known species.

The period between 1870 and 1880 was a remarkably active one, as 

is shown by the fact that more than fifty papers, of greater or less 

value, appeared during this time. As it will be impossible to notice all 

these works fully a few only of the more important will be selected and 

the others given by title only.

Caruthers contributed an article on the fossil forests near Cairo, 1 in 

which he described and figured yet another species of Nicolia, named 

in honor of the collector, Nr Owenli.

The wonderful fossil 'forests of California and the Yellowstone National Park were treated of in short articles, the former by Marsh2 and 

the latter by Holmes.3 The structure of the specimens from California 

was investigated by Dr. M..C. White, of New Haven, and pronounced 

by him to resemble the wood of Sequoia, but no further attempt was

made to determine it.

Specimens of the wood from Californian forests were later sent to Dr. 

H. Couwentz,4 in Breslau, who made a thorough examination, which 

resulted in determining them all to be coniferous and to belong to a 

single species, which he called Gupressinoxylon taxodioides.

The year 1871 saw the beginning of Professor Williamson's great 

work " On the Organization of the Fossil Plants of the Coal Measures." 

This work, published in the Transactions of the Koyal Society of London, 

already (1889) numbers fifteen parts, and is, it is safe to say, the most 

valuable contribution that has been made to our knowledge of the organization of the plants of the Carboniferous age. A consideration of 

it is deferred.

This work by Professor Williamsori is by no means his first, as he 

entered the field of paleontological" science in 1833 as a contributor to 

the Fossil Flora of Great Britain, by Lindley and Hutton. From that 

time many able articles on the plants of the Coal Measures have appoared from his pen. They are mostly short and directly to the point. 

A chronological list of most of them is given below.5

1 On the Petrified Forest near Cairo. Greol. Mag., vol. 7, 1870, pp. 306-310, pi. xiv.

"Notice of a Fossil Forest., iu the Tertiary of California. Am. Jonr. Sci., 3d ser., 

vol. 1, 1871, pp. 266-268.

3 Fossil Forests of the Volcanic Tertiary Formations of the Yellowstone National 

Park. U. S. Geol. and Geog. Snrv. Terr., Ball., vol. 5, No. 1, 1879, pp. 125-132.

4 Ueber eiu tertiiire Vorkornnien cypressinartiger Holzer bei Calistoga in Californien. Neues Jahrb.,1879, pp. 800-813, plates xm-xiv.

6 0n the origin of coal. Brit. Assoc. Adv., Sc. Rep. 1842, Notices and abstracts, 

pp. 48-49.

On the structure and affinities of the plants hitherto known as Sterubergiae. 

Lit. and Phil. Soc. Machester, Mem., 2d ser., vol.9, 1851, pp. 340-347.

Additional notes on the structure of Calamites. Lit. and Phil. Soc. Manchester, 

Proc. vol. 8, 1869, pp. 153-155.

On the structure of an undescribed typ3 of Calamodendron from the upper
30 FOSSIL WOOD AND LIGNITE. » [BULL. 56.

This period was one of greatest activity for Dr. J. W. Dawson, who 

published at least a dozen papers relating more or less to the organization of the fossil plants of Canada, Nova Scotia, etc. The most important are the following: " On the structure and affinities of Sigillaria, 

Calamites, and Calamodendrou,"' in which he describes and figures 

very perfect examples of these forms, and presents a scheme of relationship 5 a paper on Prince Edward Island,2 in which he mentioned two 

species of Dadoxylon (J). materiarium and D. Edvardianum}^ and characterized and illustrated them; and a note on the plants collected by 

Mr. G. M. Dawsou near the forty-ninth parallel, 3 in which is reported 

the occurrence of Cedroxylon, Pityoxylon, Cupressoxylon, Taxoxylon, 

and Populus.

In a collection of wood from the Mesozoic, British Columbia,4 made 

by Mr. Eichardson, Dawson detected Cupressoxylon and Taxoxylon 

among the gymnosperms, and species of Quercus, Betula, and Populus 

among the angiosperms. Specific names are omitted in all instances.

In 1875 appeared the fourth and last part of Binney's "Observations 

on the Structure of the Fossil Plants found in the Carboniferous 

Strata," 5 a work which was begun, it will be remembered, in 1868. Each

Coal-Measures of Lancashire." . Lit. arid Phil. Soc. Manchester, Proc., vol. 8, 1869, 

pp.26-37.

On the structure and affinities of some exogenous stems from the Coal-Measures. 

Monthly Mic. Jour., vol. 2, 1869, pp. 66-72.

On the structure of the woody zone of an undescribed Calamite (? Calainopitus). 

Lit. and Phil. Soc. Manchester, Mem., vol. 4, 1869, pp. 155-183.

On the organizations of the stems of Calamites. Brit. Assoc. Adv. Sc., Rep. 1870, 

Notices and abstracts, pp. 89-90.

Exogenous structures amongst the stems of the Coal Measures. Nature, vol. 4, 

1871, pp. 490-492.

On the organization of an undescribed vefticillate Strobilns from the lower Coal 

Measures of Lancashire. Lit. and Phil. Soc. Manchester, Proc., vol. 10, 1871, pp.

105-106.

On the structure of some specimens of Stigmaria. Lit. and Phil. Soc. Manchester, 

Proc., vol. 10,1871, pp. 116-118.

On the structure of the woody zone of an undescribed form of Calamite. Lit. 

and Phil. Soc. Manchester, Mem;, vol. 10, 187l; pp. 155-183.

On the structure of the Dictyoxylons of the Coal Measures. Brit. Assoc. Adv. 

Sc., Eep. 1871, Notices and abstracts, pp. 111-112. 0

On the fern-stems and their petioles, of the Coal Measures. Brit. Assoc. Adv. 

Sc., Rep. 1873, Notices and abstracts, p. 106.

1 Quart. Jour. Geol. Soc., vol. 1871, pp. 147-161, pis. vn-x.

3Report on the Geological Structure and Mineral Resources of Prince Edward 

Island. Montreal, 1871, pp. 1-51, pis. i-ni.

'Note on the plants collected by Mr. G. M. Dawson, from the lignite tertiary deposits near the forty-ninth parallel. Report by G. M.«,Dawson, Montreal, 1875. Appendix, pp. 327-331, pis. xv-xvi.

4 Note on Fossil Woods from British Columbia, collected by Mr. Richardson. AmJour. Sc., 3d ser., vol. 7, 1874, pp. 47-51.

6 E. W. Birmey. Palteontographical Society, London. Observations on the Structure of Fossil Plants found in the Carboniferous Strata. Part i, vol. 21, 1868, pp. 

1-32, pi. i-vi; Part n, vol. 24, 1871, pp. 33-62, pi. vii-xn; Part in, vol. 25, 1872, pp. 

73-96, pi. xiil-XVin; Part IV, vol. 29, 1875, pp. 97-147 ; pi. xix-xxiv.
KXOWLTON.I STUDY OF INTERNAL STRUCTURE. 31

part is complete in itself and deals with one or more of the characteristic types of the Carboniferous flora. Thus the first part takes up 

Catamites and Calamodendron. After giving the bibliography, synoiiomy, and geological position of these types, a detailed and careful description is given of the specimens upon which the memoir is founded, 

and in conclusion the resemblances and the distinctions between Sigillaria anil Calamodeudron are pointed out. In a similar manner the 

other parts describe the structure and discuss, more or less, the affinity 

of Lepidostrobus and some allied cones, Lepidodendron and Sigillaria, 

and Stigmaria. This work was a most valuable contribution to our 

knowledge of some of the intricate problems connected with the origin 

and development of vegetation.

In 1876 Conweutz 1 published his first contribution to the study of 

fossil wood, in the form of an inaugural dissertation presented to the 

faculty of the University of Breslau, This work, which gave an earnest of his future position as a thorough worker, dealt with the wood 

of the North German Diluvium. He found both conifers and dicotyledons. Of the former he mentions three species, one new, for which he 

restores the generic name of Pioites. Of the Dicotyledons he obtained 

three species of oak, for which he adopts the name of Quercites of Goppert in place of the generally accepted Quercinium.of (Juger.

In the United States, Clay pole 2 described a new fossil tree from the 

Clinton Limestone of Ohio, for which lie proposed the name of Glyptodendrou.

Renault published two elaborate memoirs 3 on the.structure of the 

plants of the Carboniferous, with the mention of' which I close the 

enumeration of the publications of this decade.

In the next decade, beginning in 1880, a glance at the literature 

suffices to show that there is au ever increasing activity and interest in 

this branch of paleontological science. Discarding older and cruder 

ideas regarding the constitution of genera and species, a knowledge of 

what can and what can not be made out b.y a study of the preserved 

remains is accepted, and "hair-splitting subtleties" give place to deductions made on a firmer scientific basis.

Among such a wealth of publications it is difficult to select any for 

special mention, as all are, in one way or another, of so much value, but 

a brief enumeration of such as possess undoubted superiority or interest will be attempted.

Schroeter's 4 examination of the fossil wood of the Arctic zone, made

1 (Jbor die versteiuteu Holzer aus dem uorddeutschen Diluvium. Breslau, 1876.

2 E. W. Claypole. Ou the occurreuce of a fossil tree (Glyptodendrou) in the 

Clinton Limestone (base of Upper Silurian) of Ohio, U. S. Geol. Mag., vol.5,1878.

3 B. Renault et C. Grand'Eury. Etudes sur le Sigillaria spinulosa et sur le genre 

Myelopteris. Paris, 1875. Structure compared de quelques tiges de la floro carbonifore. Mus. Paris, Nouvell, Archiv., pp. 313-348, pi. x-xvii, 1879. 2d Ser.. vol. n.

4 Untersuchung iiber fossile Holzer aus der arctischen Zone. In Flora fossilis 

arotica. Oswald Heer., vol. (>, Zurich, 18^0, pp. 1-36, plates i-iu..
32 . FOSSIL WOOD AND LIGNITE. I BULL. 56.

in 1880, is more than a mere description of species; it is a valuable discussion of important structural points, particularly in the Coniferse. 

He accepts the classification of Kraus and gives an analysis of the five 

groups in seeking to identify a specimen from King Charles's Land, 

which is afterwards described as new, under the name of Pinus Jolmseni. 

From the Mackenzie River three species are described, of which two are 

new, viz., Sequoia Canadensis, Girikgo spec., and Platanus dceroides 

Gopp.

In this year also Con wen tz contributed an article on the wood of 

Karlsdorf, 1 in which he speaks at some length of the various collectors and writers who have worked upon material from this locality, 

which he regards as one of the richest deposits of fossil wood known.-

After an examination of a .large series of specimens the conclusion 

is reached that they all belong to a single form, for which the new 

generic name Rhizocupressinoxylon is proposed, since they are all 

considered as representing the wood of the roots. Conwentz thinks 

three specimens to be the roots of Cupressinoxylon uniradiatum of 

Goppert, and refers them to this species under his new genus. By this 

process, which has been justly condemned, we may have a single 

species known under two accepted, but totally different, generic names, 

depending upon whether the specimens examined be regarded as stem 

or root wood. This idea, if carried out, would create untold confusion, 

and make nomenclature an end rather than a means.

Numerous other smaller roots were found penetrating the tissues of 

Rhizocupressinoxyltm, some of which were analogous to the roots of 

cypress, others to the roots of the alder. For these latter the name 

Rhizoalnoxylon is proposed, and one species is characterized.

The mycelium of a fungus was also found in the tissues of many of 

the specimens.

In the following year Dr. Conwentz worked up the fossil wood in the

collection of the Royal Geological Land Office Department of Berlin.2 

Most of it was identified as coniferous, although a few dicotyledonous 

species were detected, among them a new genus, Cornoxylon, with two 

species. Two new species of Fasciculites are also characterized by Dr. 

Stenzel, of Breslau.

In the same year Goppert and Stenzel 3 published their paper on the 

Medulosece', anew group in the Cycadacese, which they propose to take 

the place of the group to which the species of Medulose»3 were usually 

referred.

Undoubtedly one of the most important papers in 18S2 was the u Studieniiberfossile Holzer," by Johannes Felix, presented as an inaugural

'Die fossilen Holzer von Karlsdorf am Zobten. Danzig, 1880, pp. 1-47, plates

I-VIII.

2 Fossile H51zer aus der Sammlung der koniglichen geologischen Landesanstalt 

zu Berlin. Jahrb. d. k, preuss. geol. Landesanstalt, 1881, Abhand., pp. 144-171.

3 Die Medullosese. Eine neue Gruppe der fossilen Cycadeen. Cassell, 1881, pp. 

1-17, plates i-iv.
KNOWLTON.I STUDY OF INTERNAL STRUCTURE. 33

dissertation to the philosophical faculty of the University of Leipzig. 

It is a pamphlet of 81 pages and has one plate. The first part is a discussion of the characters found to be of most importance in distinguishing fossil genera and species. In dicotyledons and monocotyledons he 

considers that the genera must be in a measure comprehensive, while 

for the conifers he follows Kraus in adopting five types. In describing 

conifers, however, he falls into the grave error initiated by Conwentz 

(supra, p. 32)' of using the prefixes rhizo-, cormo-, and clado-, to distinguish wood of the root, stem, and branch. In this way a single species 

may come to have three totally different generic appellations, and in 

anything but a systematic arrangement would be as widely separated 

as the initial letters will permit. Its absurdity is well shown on pages 

46 and 47, when Cupressoxylon Protolarix of Kraus Pinites Protolarix 

G.) is given under the names of Cormocupressoxylon Protolarix, Cladocupressoxylon Protolarix, and Rhizocupressoxylon Protolarix!

In the systematic part are described woods from Europe, India, Java, 

Japan, the Islands of Cuba and Antigua in the West Indies, from Brazil, and from Australia. About forty species are enumerated, nearly 

all of which are new.

Two short papers by Schenk also appeared in 1882. The first of these 

treats of the wood collected in India by the brothers Schlagintweit,1 

and the other is a discussion of Cotta's species of the genus Perfossus.2 

Gotta described two species (P. angularis and P. punctatus), the originals of which Dr. Scheuk had opportunity of examining in the Dresden 

Museum. He found them to be unquestionably palm-like in structure 

and proposed the name Palmoxylon for them, a name which has been 

since adopted for all palm wood.

In a paper on the plants of the Brian (Devonian) and Upper Silurian 

formations of Canada,3 Dawson again defends his Prototaxites and 

affirms as his opinion that it is " a cotemporary of that prototype of 

gymnosperms Aporoxylon and similar plants of the Devonian," and has 

a decided likeness to the modern Taxus in structure. Of the genus 

Dadoxylon he describes one new species, which is the fifth reported 

from the Middle Erian of America, u an interesting confirmation," as he 

says, u of the facts otherwise known as to the great richness and variety of this ancient flora."

Other papers during this year were published by Felix,4 Beck,5 and 

others.

1 Dr. A. Schenk. Die vou den Gebriidern Schlagintweit gesaramelten fossilen 

Holzer. Bugler's bot. Jcihrb, vol. 3> 1882, pp. 353-358.

8 Die Perfossus-Arteti Cotta's op. cit., pp. 483-486.

3 Geol. Surv. Canada, pt. 2. Montreal, 1882. Pp. 95-142, pis. xxi-xxiv.

4 J. Felix. Beitriige zur Kenntnies fossilen Couiferenholzer. Engler's bot. Jahrb., 

vol. 3, 1882.

6 Richard Beck. Das Oligocan von Mittweida mit besonderer Beriicksichtigung 

eeiner Flora. Deut. geol. Gesejl,, Eeitachr., volt 34, 1882? pp, 7-35-770, plates XXXI,

XXXII.
34 FOSSIL WOOD AND LJGNITE. [BULL. 56.

The year 1883 witnessed the production of a goodly number of valuable contributions, mostly from well known authors.

Two by Felix are deserving of special notice. Under the modest 

title of " TJutersuchungen iiber fossile Holzer," 1 he gives much useful 

information concerning Tertiary dicotyledonous woods. The genera 

mentioned are Laurinoxylon, Lillia, Helictoxylon, Sapotoxylon, Querciniuin, and Ficoxylon. The discussion of the genus Quercinium is particularly interesting. In the second part of this paper material from 

other horizons is described, among which are roots of plants found 

penetrating other tissues. The name Ehizonium of Corda is adopted for 

these intruding roots except in one case, where it was clearly of the nature 

of a cypress, when it was called Bhizocupressoxylon, after Conwentz.

The other work by Felix is a monograph of the fossil wood of the 

West Indies.2 In the introduction he again speaks of the difficulty 

attending a satisfactory determination of angiospermous wood as compared with that of gymnospermous wood, and concludes, after having 

examined over 400 living species, that the genera founded on fossil 

forms must be regarded as comprehensive. Salicinium, for example, 

will include wood of Populus as well as that of Salix.

Most of the material was from the Island of Antigua, from which 

fossil wood had been known since the time of Scheuchzer. The following genera of dicotyledons were identified: Ttenioxylon, Zittelia, Cassioxylon, Schmideliopsis, Anacarclioxylon, Ebenoxylon, and Helictoxylon. The monocotyledons all belong to the genus Palmoxylon, of which 

ten species are described and figured.

In 1883 also appeared the first volume of Goppert and Menge's magnificent " Flora desBernsteins," 3 a work which neither of the illustrious 

authors-lived to complete. The second volume was written by Dr. H. 

Conwentz, and appeared in £886. The first volume is the most valuable 

to the student of internal structure, since it contains the results of the 

examination of the internal structure of such fragments of wood as were 

preserved in connection with the amber. Goppert first reviewed the 

work that had been done by Kraus on the structure of living conifers. 

Many species were described, some from characters taken from the 

wood, others from, leaves, flowers, and fruits, all being illustrated by 

beautiful colored plates. In conclusion, an elaborate account is given 

of the origin and relations of the amber flora.

The fossil wood of the Libyan Desert, by Scheiak,4 is a valuable

'Dent. geol. Gesell., Zeitschr., vol. 35, 1883, pp. 59-91, plates n-iv. 

2 Die fossilen Holzer Westindiens. Sanimlnug palaeontologischer Abhaudl.,Ser. i, 

part i. Cassol, 1883, pp. 1-32, plates i-v.

3 H. R. Goppert und A. Menge. Die Flora des Bernsteins und ihre Beziehuugeu zur 

Flora tier Tertiiirformatiou uud der Gegenwart. Erster Baud, Danzig, 1883; Zweiter 

Baud, Danzig, 1886.

4 Fossile Holzer. In Beitriige z. Geol. u. Palaeout. d. libyschen Wiiste und der 

angreuzenden Gebiete von Aegypten, Palaeontograpliica, vol. jcxx, 1883, pp. 1-20, 

plates i-v,
KNOWLTON.) STUDY OF INTERNAL STRUCTUEE. 35

systematic paper. In it the conifers are represented by one species of 

Arancarioxylon; the monocotyledons by two species of Palmoxylon; 

the dicotyledons by the following genera, each, except the first, with 

a single species: Nicolia, Acacioxylon, Rohlfsia,Jordania, Laurinoxylon, 

Ccupparidoxylon, Dombeyoxylon, and Ficoxylon. These last, it will be 

seen, are mostly named frolicsome living dicotyledon which they most 

nearly resemble.

In 1884 the most important contribution was that of Beust,1 in which 

he describes and figures several species from the Lower Miocene of 

Greenland.

One of the new species Araucarioxylon Heerii is the first of the genus 

found in Greenland, while the other, Libocedrus Sabiniana, is referred 

to a species already described by Heer from twig impressions.

By far the most valuable part of this paper is the elaborate discussion

entered into in seeking a name for the Libocedrus. He examined critically many living conifers to ascertain, if possible, whether the characters considered of most importance in describing fossil forms had any 

value in distinguishing living genera or species. The result was in the 

main negative for single or special characters, such as thickening of 

the cell walls, pits, or markings on the medullary rays, etc., but a combination of all possible characters was found to be of diagnostic worth. 

Thus the number and the size of the cells in the medullary rays he 

considers unreliable, but the relative volume of the ray cells as compared with the wood cells, among which they are placed, he considers 

of the highest value.

He also gives four elaborate tables, in which are presented systematized accounts of a microscopical examination of all recent and fossil 

species belonging to the groups Araucarioxylon and Cupressinoxylon. 

These tables, which are invaluable to the general student, represent 

hundreds of careful observations.

Felix also published an excellent paper in 1884, "Die Holzopale 

TJngarns in palaeoutologischer Hinsicht," 2 in which he established the 

new dicotyledonous genera Alnoxylon, Liquidambaroxylou, and Staubia, 

and described many new species belonging to well known genera. The 

most important part is his admission of the incongruity of the use of 

the prefixes rhizo, cormo, and clado to indicate wood of different parts 

of the plant. It works, as he admits, the greatest confusion in nomenclature, and he wisely concludes to abandon it. In the description of species, if one is fortunate enough to obtain material from all parts of the 

plant, it is best indicated by simple headings " root wood," " stem wood," 

or " branch wood," as the case may be. We have not three distinct genera, but simply a very perfect representation of a species of one genus.

Another important work which appeared during this year was J.

1 Fritz Beust. Untersuchung iiber fossile Holzer aus Gronland. Allgem. schweiz, 

Gesell., neue Denkschr., vol. xxix, 1834, pp. 1-43, mit. 4 Tabellen u. 6 Tafelu, 

* Jalirb, d, 1?. ung. geol. Austalt, vol. 7, 1884, pp, 1-43, plates t-jv,
36 FOSSIL WOOD AND LIGNITE. [BOLL. 56.

Schinalhausen's paper on the Tertiary flora of the southwestern part of 

Eussia.1 The paper is divided into four parts, the first three of which 

are devoted to descriptions of leaves, fruits, etc. The fossil wood described in the fourth'part is from the Spondylus (Eocene) zone of Eussia.

In regard to naming fossil wood, Schmalhauseu concludes that the 

generic as well as the specific names must be comprehensive and possibly include several forms that would be regarded as distinct if we were 

provided with all the essential parts. Following out this line of argument he refers nearly all his specimens to .the genus Cupressinoxylon, 

which, according to Mercklin, Schroeter and others, he considers may 

probably represent the wood of Sequoia. The well known structural 

resemblances between the wood of living Sequoias and the wood of the 

fossil genus, together with the marked abundance of species of Sequoia 

during Tertiary times make this seem very probable.

Six species are then described, three of which are considered to be 

new to science ( Gupressinoccylon glyptostrobinum, C. Mercklini, and Pityoxylon microporosum). Three finely executed plates illustrate the structure of the wood.

Other papers were published during 1884 by Vater,2 Solms-Laubach,3 

Hofmann,4 and others.

In 1885 Dr. Coiiwentz described a collection of wood from the Eio 

Negro, in Patagonia,5 which possesses features of interest. The species 

are mostly coniferous and are all new to science. They are distributed 

as follows: Cupressinoxylon, four species; Araucarioxylon, one species 

and Glyptostroboxylon, the latter a new genus. The single angiosperm 

is called Betuloxylon, under which it is proposed to include the genus 

Betuliniuin of linger. A list of all the known species is given.

Eenault contributed, also in 1885, a valuable paper on the structure 

and position of the genus Astroinyelon.6 It is illustrated by several 

fine plates.

In 1886 Dr. Felix published a continuation of his "Untersuchungeu," 7

1 J. 'Scbmalnausen. Beitriige zur Tertiiirflora Siidwest-Russlands. Palteontologische Abhaudl. von Dames u. Kaiser, vol. 1, Berlin, 1884, pp. 285-336, plates xxvmXLI.

2 H. Vater. Die fossilen Holzer der Phosphoritenlager des Herzogtbums Braunschweig. Deutsch. geol. Gesell., Zeitschr., vol. 36, 1884, pp. 783-857.

3 H. Graf zu Solms-Laubach. Die Coniferenformen des deutschen Kupferschiefers 

uud Zechsteins. Palseontologische Abhandl. von Dames u. Kayser, vol. 2, Berlin,

1884. pp. 81-116, plates xn-xiv.

4 Hermann L. Hofmann. Untersuchungen iiber fossile Holzer. Inaug.-Diss. an d. 

Univ. Leipzig. Halle a S., 1884, pp. 1-44.

6 Dr. H. Couwentz. Sobre algunos, iirboles fdsiles del Rio Negro. Academia National de Ciencias en C6rdoba (Republica Argentina), Boletin, vol. 7, Buenos Aires,

1885. pp. 435-456.

6 B. Renault. Recbercbes sur les ve~g6taux fossiles du genre Astromyelon. Annales des Sciences G6o]ogiques, vol. 16, 1885, pp! 1-34, pi. 7-9.

7 Dr. J. Felix. Uutersucbungen u'ber fosgile Holzer. Z.w0Jte9 Stftck, Peut.geo.li

aes.ell., ZeitecJu'., vol. 38, l§86, pp. 483-492, plate XH,
KNOWLTON.] STUDY OF INTERNAL STRUCTURE. 37

in which he describes six species, distributed as follows: Pityoxylon 

inceguale, from Alaska; Pityoxylon Krausei, from the Little Missouri, 

in Dakota; Cupressoxylon erratiaum, Mercklin, from Copper Island, in 

Bearing Strait; Cupressoxylon, cf. sylvestre, Mercklin, from Little Missouri, Dakota; Laurinium Meyeri, from New Guinea, and Tcenioxylon 

eperuoides, from Negro Island, in the Philippines.

In a short paper 1 read before the American Association at the Buffalo meeting (August, 1886), Prof. E. W. Claypole reports the occurrence 

of Dadoxylon antiquius and D. Newberryi in the Carboniferous of Ohio. 

Other wood was found, but so poorly preserved as to be useless for 

purposes of determination.

Papers which were of less value were published by Blanckenhorn,2 

Beck,3 and others.

To treat in anything like an exhaustive or satisfactory manner the 

elaborate memoir of Professor Williamson on the organization of the 

fossil plants of the coal measures, of which mention was made above, 

would require much more space than is at my disposal, and an analysis 

of the contents and value of one of them must be taken as a sample of 

all. These papers have appeared from time to time, since 1871, in the 

Philosophical Transactions of the Eoyal Society of London. The first 

is on the Calamites, a group of Carboniferous plants that has been in 

confusion from time immemorial. In the beginning Professor "Williamson propounds four questions concerning this group, as follows:

1. Do all the well known plants hitherto designated Calamites belong to one 

natural family, or there are two groups of these objects the one cryptogamic, represented by the true Calamites, and the other phanerogamic, and represented by the 

Calamodendron of Brouguiart ?

2. Are there several genera, divisible into numerous species, with well marked 

internal characteristics, or are there but few specific types, each of which, though 

they are all constructed upon one common plan, exhibits a wide range of variability 

in the details of its internal organization.

3. What are the casts commonly known as Calamites, and what parts of the plants 

do their varied superficial markings represent ?

4. To what living plants are these fossil forms most closely related?

To all these questions the specimens in hand suffice to give answers, 

according to Wiiliamson, who, after describing minutely the structure 

of his specimens, proceeds to draw the conclusions from them.

To the first question he replies that the Calamites are undoubtedly 

cryptogamic, but that they possess a much higher organization than is 

seen in any of the living cryptogams, and there is proof that they have 

an undoubted exogenous mode of growth.

J E. W. Claypole. Preliminary note on some fossil wood from the Carboniferous 

of Ohio. Am. Assoc. Ady. Sc., Proc., vol. 35, 1886, pp. 2197220.

2 Dr. Max Blauckenhorn. Die fossile Flora des Buntsandsteius und des Muschelkalkes cler Umgegend von Commern. Palaeontographica, vol. 32, 1886, pp. 117-154, 

plates xv-xxi.

3 Richard Beck. Beitrage zur Kenutniss der Flora des sachsischen Oligociina. 

Deut. geol. Gesell., Zeitschr., vol. 38, 1886, pp. 342-352, plate vii.
'38 FOSSIL WOOD AND LIGNITE. [BULL. S6.

To the second question he replies that we have two very distinct types 

of calainites clearly distinguished from one another by presence or absence of certain structural peculiarities.

The casts called Calamites he regards not as the result of filling up 

of cavities formed by decay, but by filling of cavities formed naturally 

by a process of absorbtion during the life of the plant.

That the modern Equisetacese are the only living representatives with 

which the Calamites can be compared he does not doubt.

Many elegant illustrations accompany the article.

In a similarly exhaustive manner are taken up the Lepidoendra, Sigillariae, Asterophyllites, etc.

GEOLOGICAL- AND GEOGRAPHICAL DISTRIBUTION OF THE 

POTOMAC FORMATION.

It is now necessary to discuss briefly the geological position and geographical distribution of the formation from which the wood herein described was obtained. This formation was described at length by Prof. 

W. B. Eogers in the annual report of the geological survey of Virginia for 1S40, 1 where it was designated as the Jurasso-Cretaceous or 

Upper Secondary Sandstone. It is laid down upon the primary rocks 

along their eastern boundary in the State of Virginia and is in its turn 

overspread by undoubted Tertiary strata. The Potomac formation, the 

name by which it is now more generally known, is the one proposed by 

the U. S. Geological Survey to distinguish it as a local formation and 

to fix more definitely its position in the geological scale. From the 

palaeobotanical evidence available in 1885 Mr. W. J. McGee considered 

it to be " Lower Cretaceous in age the American equivalent of the 

European Neocomian?' 2 Prof. William M. Fontaine, on the other

hand, from an exhaustive study of the leaf and cone impressions, is 

inclined to regard it as belonging to the Wealdeu, while Prof. O. C. 

Marsh, who has studied the animal remains, regards it as Jurassic.

As to the nature of the material comprising this formation Eogers 

says : 3 "These strata consist of sandstones, slates, shales, and conglomerates, and, as might be anticipated, display much variety as to color, 

texture, and solidity." In and about the District of Columbia, Mr. 

McGee describes it as being composed of " mottled clays, gravels, and 

laminated sands and clays." It is thus observed to present considerable diversity of character and, as might be expected, offers in the 

different members very unequal conditions for preservation of organic 

remains. It attains in some instances, as along Potomac Creek, an observed thickness of from sixty to seventy feet, but in general the expos1 See Geology of the Virginias, pp. 437-449. New York, 1884.

2 The Geology of the District. The Evening Star, Washington, July 11, 1885.

3 Op. oit., p. 442.
RNOWLTON.I OCCURRENCE OF ORGANIC REMAINS. 39

ures are much less than this, being rarely over thirty or forty feet. Its 

total thickness must be two hundred or three hundred feet, or even 

more.

The geographical distribution, both on the north and on the south, 

has been extended considerably beyond the points indicated by Professor Kogers. Thus the southernmost point at which the Potomac formation has been detected is Weldon, North Carolina, where it was 

observed by Messrs. McGee, Foutaine, and Ward, in July, 1885. From 

this point it extends almost directly north, occurring in irregular and 

scattered outcrops, to the Nottoway Eiver, which was indicated as the 

southern limit by Eogers. From Petersburgh it extends northward in a 

narrow belt, offering good exposures on the Appomattox, James, South 

Anna, North Anna, Eappahannock, and Potomac Rivers. It touches 

the Potomac at Acquia Creek, and, extending up past Mount Vernon, 

which Eogers considered as the northern terminus, embraces a large 

portion of the District of Columbia. Thence it extends to Baltimore, 

where extensive outcrops containing abundant plant remains have 

been observed by Mr. McGee. The most northern point at which this 

formation has been identified by fossils is near Havre de Grace, at the 

head of Chesapeake Bay. This outcrop was visited by Messrs. McGee 

and Ward in 1885, and a few plant remains were obtained, but a more 

extended exploration is necessary to complete our knowledge of this 

locality. Quite recently gravelly deposits, evidently representing this 

formation, have been observed by McGee on the highlands of northeastern Maryland, northern Delaware, and southeastern Pennsylvania, 

overlooking Chesapeake and Delaware Bays, as far north as the Schuylkill Eiver. It may yet be found that the Earitan clays of New Jersey 

rest conformably upon the Potomac formation, but of the truth of this 

we cap only conjecture at present.

THE ORGANIC EEMAINS AND THEIR MODE OF OCCURRENCE.

The organic remains of the Potomac formation occur principally in 

lenticular pockets of a hard, bluish clay, which bear evidence of having 

been transported in mass from the original bed in which they were laid 

down. These pockets vary in their dimensions, some being only a few 

feet in length and one or two feet in thickness, while others are two or 

three rods long and from three to ten feet thick. It is more than probable that originally this material was deposited in shallow water, which 

was fresh, or at most but slightly brackish. An unknown thickness, 

filled with the de"bris of vegetable growth, was here accumulated, after 

which there was a gradual uplifting of the land. This newly emerged 

land was now subjected to the powerful action of moving water, which 

cut down and transported a large portion of it, leaving now and then 

these irregular or lenticular masses, which were eventually surrounded 

and covered by a lighter material, and the whole was finally buried 

under the Tertiary.
40 FOSSIL WOOD AND LIGNITE. [BULL. 56.

Good exposures of this formation, containing lignite and silicifled 

wood, occur at Fort Washington, White House Landing, and Acquia 

Creek on the Potomac ; at Dutch Gap and vicinity, on the James Biver; 

and also in the cities of Washington and Baltimore, where excavations 

have been made. Cuts along the lines of railways which pass through 

this formation often give good sections. Most of the specimens described in the following pages came from these localities.

The wood of this formation occurs under two widely different conditions, viz: as lignite and as silicified wood. There seems to be almost 

no transition between the two forms, although in one instance, in a 

silicified specimen from the new reservoir, Washington, a few small lignitized areas were detected. There is reason for supposing, however, 

that some of the silicified forms are also represented in a lignitized 

state, that is, owing to different conditions of fossilization some specimens of a species were silicified, while others were turned to lignite.

The lignite is much more abundant than the silicified form, occurring 

in the above mentioned lenticular masses in pieces of considerable size 

and in the loose surrounding material as minute fragments, which shows 

that this latter is the result of the wearing away of a large part of the 

original deposit. One of the largest specimens noted was found at Fort 

Washington. This was a log about five feet in length, eight inches in 

width, and four in thickness. A cross-section of this specimen of course 

would have been lenticular, showing that it had been subjected to great 

pressure. A transverse section, as seen under the microscope, (PI. I, 

Fig. 2), shows the cells completely collapsed and distorted by the pressure.

In color this lignite is almost uniformly jet black, in a few cases being 

of a slightly brownish, cast. It has a specific gravity of about 1.333. 1 

and breaks with a true conchoidal fracture like ordinary anthracite. 

When thus broken it does not exhibit superficially the slightest trace 

of organic structure (see PI. I, Fig. 5 c), although careful microscopic 

examination of thin sections shows it to be generally present. It may, 

however, be split along certain lines, notably in a direction parallel to 

the medullary rays, where very plain structure shows superficially. 

Viewed as an opaque ooject (PI. I, Fig. 5), the outlines only of the wood 

cells aiid medullary rays are detected.

Supposing a priori that all parts of this lignite must exhibit traces, 

at least, of organization, its intense blackness naturally becomes a serious 

obstacle in the way of a satisfactory examination, since, in order to 

make a successful study with the higher powers of the microscope the 

specimen must be thin enough to be viewed by transmitted light. An 

attempt was made to grind down sections, after the usual manner of 

cutting rock sections; but, even when the sections were so thin as to 

begin to break in fragments and be torn from the slide, they still remained too opaque for even a ray of light to pass through. Other

1 Kindly determined for me by Mr. George P. Merrill, of the U. S. National Museum.
DESCRIPTION OF LIGNITE. 41

methods, as incineration, boiling in acids, etc., were equally unsuccessful. The method finally adopted, and which proved eminently successful, was that recommended by Griffith and Heufrey in their Micrographic 

Dictionary, second edition (p. 178), for the examination of coal. The 

specimens are macerated for a week or more in a strong solution of 

carbonate of potash, "at the end of which time it is possible to cut 

tolerably thin slices with a razor. These slices are then placed in a 

watch glass with strong nitric acid, covered, and gently heated; they 

soon turn brownish, then yellow, when the process must be arrested by 

dropping the whole into cold water, or else the specimen would be dissolved. The slices thus treated appear of a darkish amber color, very 

transparent, and exhibit the structure, where existing, most clearly." 

The specimens are then carefully washed in pure water and are best examined in glycerine, and may be mounted permanently in cells of this fluid.

The translucency obtained by this process is brought about by the 

dissolving out of the hydrocarbons by the potash. This shows that 

there can be little or no free carbon present, else it could not be dissolved 

by the liquids used. The intense yellow color produced is probably due 

to the presence of picric acid, of which, owing to its great coloring 

power, only a trace would be necessary.

The silicified wood occurs in situations similar to the lignite, but generally in larger pieces. One trunk seen by Messrs. McGee and Ward 

at the new reservoir, Washington, was about twenty feet below the 

surface and was reported to have been between thirty and forty feet 

long. It had a diameter of nearly two feet and was but slightly flattened. Other smaller specimens from the same locality were more 

flattened, and a transverse section as seen under the microscope shows 

the cells to be distorted by pressure. Generally, however, the tissue is 

very perfectly preserved in the silicified specimens and admits of careful dissection and study.

In color the specimens vary from almost white to jet black, sometimes 

showing a transition between the two colors in the same specimen. The 

only examples of a decided yellow were collected by W. J. McGee in'a 

cut on the Baltimore and Ohio Eailroad half way between Montello and 

Eives Station, D, 0. These were small fragments; yet they have the 

structure very perfectly preserved in places.

The method employed in preparing these woods for study is that commonly followed in the preparation of petrographic specimens, viz: slicing 

.and grinding to the requisite thinness and mounting in Canada balsam.

SYSTEMATIC DESCRIPTION OP LIGNITE.

A great many specimens of lignite have been examined by the process mentioned above from Baltimore, from the new reservoir and vi. 

cinity, Washington, from Fort Washington on the Potomac, from the 

Dutch Gap on the James River, and from other localities throughout 

the area covered by this formation and the result, although not as sat-
42 FOSSIL WOOD AND LIGNITE. [BULL. 56.

isfactbry as could be wished, is probably all that could be expected under the circumstances. The most casual examination shows' that this 

material has been subjected to great pressure, which has so entirely 

crushed and distorted the cellular elements that it is difficult in many 

.cases to recognize the original form. The examination of a large series 

of sections serves, however, to give a pretty correct general idea of it.

A transverse section like that given in Plate I, Fig. 2, shows the 

lumen of the cells to be almost entirely closed up by lateral pressure. 

This specimen, which was collected in the new reservoir, Washington, 

by Mr. McGee, is one of the best obtained. In most of those studied 

the pressure had seemingly been greater, and consequently the original 

outlines of the cells were more difficult of determination, as they had 

been crushed and crowded upon one another in great confusion.

A radial section shows the medullary rays to be in great abundance 

(Plate I, Fig. 3), and, like the wood cells, to have been considerably distorted by pressure. In a few cases some of the cells of the rays were filled, 

before being subjected to this pressure, with a hard substance, which 

was more resistant to pressure, and consequently they retain nearly their 

original form. The infiltration of this substance must have been quite 

accidental and without any regularity of action, since not one cell in 

twenty is thus preserved. The irregular distribution of these ray cells 

is shown by a glance at the tangential section (Plate I, Fig. 1). The 

number of cells entering into the composition of each ray varies considerably, ranging in vertical section from as few as two or three to as many 

as fifty or more. By this is to be understood the average of all the specimens examined. In some of the specimens, as for example those from 

the new reservoir, the rays are rarely ever more than twenty cells high, 

while in others there may be as many as forty or fifty. In most cases 

the rays are but one cell broad, although in a few instances sections have 

been obtained with the rays two cells broad. In one poorly preserved 

example there seemed to be several cells, perhaps as many as four, with 

a larger one in the center. This appearance may have been the result of 

pressure, and, if so, would of course have no value, but if natural it 

would indicate that the specimen belonged to the genus Pityoxylon. It 

was, however, too indefinite to be more than suggestive.

As for pits or markings on the rays, they seem to have .been pretty 

generally wanting, or, at most, rarely to have been preserved in a satisfactory manner. They have been observed only in one instance (Plate I, 

Fig. 3 b). where only two pits or circular markings were noted. In radial sections the cells that have been filled with the harder substance 

present a slightly different appearance, being granular. I at first mistook this granulation for evidence of markings on the walls, but a more 

careful study convinced me that it was due to the above cause.

In tangential sections the medullary rays are seen to be very numerous, but this appearance is due partly to the collapsing of the wood-cells 

by pressure, by which they are made to occupy nearly one-third less
KNOWLTON.) DESCRIPTION OF SILICIFIED SPECIES. 43

space than when in a turgid condition, thus bringing a greater number 

of rays into the field at once. Most of the cells are crushed flat, only 

those above mentioned escaping.

In regard to the identification of this lignite it is manifestly impossible to attempt more than an indication of its general character and 

position. That it is coniferous is beyond question. The absence of 

wood elements other than trache'ids, which were provided in some cases 

at least with bordered pits, and the number and arrangement of medullary rays, make the coniferous nature clear. From the abundance of 

the genus Cupressinoxylon in the Potomac Formation, as shown by 

the silicified examples, it is probable that most of the lignite may be 

also of this genus, particularly as there is in many cases a marked resemblance, so far as I am able to interpret the distorted structure, 

between it and some of the species described from silicified specimens. 

This is, however, little more than conjecture.

The variation in height and in breadth of the medullary rays, as 

described above, indicates that several species, as species of fossil wood 

are understood, entered into the formation of this lignite. Whether 

these characters are of sufficient importance to merit specific distinction 

is a question still undecided.

SYSTEMATIC DESCRIPTION OF SILICIFIED SPECIES.

CUPRESSINOXYLON Goppert. 

Cupressinoxylon 1 Goppert, Mon. foss. Conif., 1850, p. 196.

This genus, as it is now emended, is a somewhat comprehensive one, 

including, according to Kraus, what were regarded at one time as several distinct genera. Thus we have Thuioxylon of linger and End-, 

licher, Physematopitys of Goppert, a part of Pinites of Goppert, and 

Pence of Witham, all embraced under Cupressiuoxylon. This modern 

extension of the generic characters in the study of fossil wood is the 

direct result of our more extensive and exact knowledge respecting the 

internal structure of living forms, for in this department, as in all the 

departments of paleontology, our knowledge of the fossil types is derived, almost entirely from comparison with their most nearly related 

living representatives. As our knowledge of the'internal organization 

of living conifers has been gradually worked out by Goppert, Kraus, 

Beust, and others, the fact has become more and more apparent that 

types founded upon these characters alone must be.regarded in a measure as comprehensive; that is, species founded upon external characters 

may so much resemble one another in internal structure that it will be 

impossible to distinguish them; and in like manner what are regarded 

as genera may resemble one another to such an extent that, if we had

1 There is a considerable diversity among authors as to the way this \vord is to be 

spelled, but I prefer to follow Goppert, not only because his name has the claim of 

priority, but because it is etymologically correct. The root is from the tribal uame 

Cupressinete, and not simply the generic word Cupressus.
44 FOSSIL WOOD AND LIGNITE. (BULL. M.

them only in a fossil state, we should be obliged to refer them to a 

single type. We are able in all cases, however, to recognize families 

and tribes, and, as the°above example is an extreme case, we are able to 

distinguish genera in many instances.

This looseness, or expansiveness, of structural characters does not 

by any means invalidate the results obtained from their study, for, as 

Willianison truly says, nothing can have the value that a study of 

internal organization has; "it is the basis upon which all recent botany 

should rest," and through it and by it must we seek for the explanation of many of the otherwise inexplicable problems of the origin of 

various types of vegetation and of the line of development that has been 

followed by them. If it can be shown that a number of species or 

genera have an identical or but slightly dissimilar cellular structure, 

then we have an argument that can not be controverted of their community of origin, for the characters drawn from leaves, flowers, or fruits, 

upon which recent species are founded, are the most plastic and those 

most readily modified by change of environment. The structural elements, on the other hand, are more permanent, and undergo change 

and modification much more slowly. As proof of the value of this 

method may be cited the now very generally acknowledged systematic 

position of the Coniferae. Botanists have generally placed the Conifer® 

between the monocotyledons and dicotyledons on account of their exogenous mode of growth, but paleobotanists have all along insisted that 

their true position was between the cryptogams and the phanerogams, 

and have substantiated their arguments by showing that there is a gradual transition from some of the higher cryptogams, which are only known 

in a fossil state, to undoubted conifers. So indistinct is this line of demarkation that many eminent paleobotanists have placed the Sigillarise, 

which are now believed to be true cryptogams, among the Coniferaj.

The genus Cupressinoxylon is characterized by Kratis as follows: 1

Lignum stratis concentricis distinctis, angustis; cellulis prosenchymatosis pcrosis, 

poris magnis, rotundis, uni vel pluriserialibus, oppositis; cellulis resiuiferis creberriuiis, ductibus resiniferis nullis ; radiis medullaribus siinplicibus.

The various specimens that I have examined from the Potoinac Formation belong, with one exception, to this genus, which is the largest 

one founded upon internal structure. Most of the specimens are rather 

small, although a few, as for example, those from the new reservoir, 

Washington, are from trunks that were of very large size. In their 

structural details these specimens exhibit affinities with some described 

species, but as they differ in one or more of the characters that are considered of importance I have described them all as new. The view of 

this specific distinctness is still further strengthened by the fact that 

the species most nearly related to them come from different horizons 

and also from distant localities. The question of relationship will be 

discussed under each species.

1 In Schiinper: Trait<$, Pal. V6g. Vol. II, p. 374.
KNOWLTON.] DESCRIPTION OF SILICIFIED SPECIES. 45

CUPRESSINOXYLON PULCHELLUM, 11. 8p.

Plate II, Figs. 1-4.

Description. Annual ring moderately distinct, 1.25 to 3mm broad; 

trache'ids small, rather thick walled, with bordered pits only on radial 

walls, these in a single row; medullary rays numerous, simple. 1 to 15 

cells high ; resin ducts numerous, of a chain of short thin walled cells:

The specimen upon which the above species is founded was collected 

by Mr. Ira Sayles, of the TJ. S. Geological Survey, at Spring Hill, on the 

bank of the Appomattox River, half way between Petersburg and City 

Point, Va. It is a perfectly silicifled fragment about 12cra in length and 

8cm in diameter. In transverse section the pith is very clearly observable, being a little to one side of the exact center of the specimen. 

The medullary rays show very distinctly even to the naked eye. The 

annual rings are much less distinct than the rays, but may be observed 

with a small hand-glass. The general color of the specimen is yellowishgray, discolored in places by patche's of black, due to the infiltration of 

iron.

Microscopic analysis. Transverse section: As above stated, the 

pith is well preserved and is found to consist, when viewed under 

the microscope, of numerous large, rather thick walled cells, with an 

elliptic or nearly circular outline. The larger cells, which have a 

diameter of from ,05mm to ,OSmm, occupy the center, from which they decrease in size and pass more or less gradually into the medullary rays. 

The rays are very numerous and pass in nearly a straight line to the 

circumference. Unfortunately no trace of the bark remains. The 

trache'ids are arranged with great regularity in radial rows, and are remarkable for their small size, particularly where they are in contact 

with the pith. As the medullary rays diverge, new layers of trache'ids 

are intercalated to fill up the space, as shown in Plate II, Fig. 2. The 

line of demarkation between the annual layers js generally well defined, 

the fall wood (Herbstholz of the Germans) consisting of from five to 

eight compressed cells in each radial row. The spring wood (Friihliugsholz) consists of much larger cells, which have a diameter of from 

.025mm to .035m"'. These cells are more nearly hexagonal than the others, 

and decreasing gradually in size, pass into the next ring of fall wood.

Radial section: In this section the trache'ids are seen to be long and 

provided with a single longitudinal row of bordered pits, which have 

an average outer diameter of from .017mm to .021mm. The inner circle of 

the pits is rather small, with a diameter of from .005ram to .006mra . The 

medullary rays are cut up into comparatively short cells, each one covering the space of five or six of the trache'ids; markings seem to be 

absent from the walls of the rays, but the real state of affairs may be 

masked by the petrifying material, which has evidently somewhat disorganized the original structure. The resin ducts are numerous, as is 

shown by the presence of two m the section figured. (Pi, II, Fig. 1),
46 FOSSIL WOOD AND LIGNITE. [BULL. 56.

These ducts (Harzzellen of the Germans; conduits re"sineux simples 

of the French) consist of a chain of short, regular cells, which are 

slightly constricted at the ends. The individual cells are from .OSmra to 

.15mm in length, and are usually filled with minute globules of darker 

matter, represented by dots in the drawing.

Tangential section: In this section the medullary rays are seen to be 

very abundant. They are always simple and consist of a single layer, 

which ranges from 1 to 15 cells in height, the average number being 

about seven or eight. The tracheids do not show bordered pits on the 

tangential walls, a-fact of considerable importance.

Tnere are points of resemblance between the Potomac form and the 

following described species: Cupressinoxylon sylvestre Mercklin (Pal^eodendrol. ross. p. 58, pi. xiii, figs. 1-6), Cupressinoxylon Breverni Merckliu 

(op. cit., p. 71), Cupressinoxylon pachyderma Goppert (Mon. foss. Conif., 

p. 199, pi. xxv, figs. 1-2), Cupressinoxylon juniperinum Goppert, Tlmyoxylum juniperinum Nug., (Chlor. prot., p. 31), and Cladocupressinoxylon 

Protolarix Felix (Stud. lib. foss. Holz., p. 46). These species all differ, 

however, in one or more characters, which are considered of taxonornic 

value, from the Potomac species, which I have consequently ventured 

to describe as new. More complete and perfect material may show the 

relationships to be closer than is now suspected; but even in that case 

it would be doubtful whether the species were identical, coming as they 

do from such widely different geological and geographical positions.

CUPRESSINOXYLON MCGEEI, n. sp.

Plate II, Fig. 5; Plate III, Figs. 1-5.

Description. Annual ring very distinct, from 2mm to 4.5mm broad; tracheids remarkably large, thick walled, closely covered with from one to

three rows of large bordered pits on the radial walls and a few scattered 

ones on the tangential walls; medullary rays simple, from 2 to 49 cells 

high, covered on the lateral walls with numerous oblong pores; resin 

ducts simple, numerous, composed of a chain of thin walled cells.

The type of this species was collected by W. J. McGee, of the U. S. 

Geological Survey, from excavations made for the new reservoir of the 

water-works extension, Washington, D. 0. It had originally a length 

of nearly forty feet and a diameter of almost two feet. It was somewhat flattened by pressure, the shorter diameter being considerably 

less than the longer. The trunk was exposed at a depth of about 

twenty feet below the surface, and must have belonged originally to a 

tree of large size. To the naked eye the annual rings are very indistinct. The medullary rays, however, are easily observed and are seen 

to pursue a very tortuous course, due, in part at least, to the dislocation caused by the pressure to which it had been subjected. The bark 

was not preserved in any of the pieces examined.

Microscopic analysis, Transverse section; This section shows the
KNOWLTON.] DESCRIPTION OF SILICIFIED SPECIES. 47

trache'ids to be arranged in strict radial rows, and also indicates their 

great size. The annual ring, as above stated, is broad, consisting in 

some cases of as many as fifty or sixty of the larger and from ten to 

sixteen of the smaller thick-walled cells. The larger cells are mostly 

quadrangular in outline and have a diameter in some instances of 

.080""", the average being about .068miu. The cells of the fall wood 

have very thick walls and are much flattened. Intercellular spaces 

are frequently observed, particularly where additional rows of trache'ids have been intercalated (PI. Ill, Fig. 1. c). The medullary rays 

are moderately numerous.

.Radial section : The large size of the trachfvids is very clearly shown 

in this sectionj most of which is made up of summer wood. The trache'ids in the fall wood are, of course, much smaller and are covered 

with but a single row of pits. The bordered pits are very close together on the summer wood and are always in two and ill some exceptionally large cells in three rows. They are also very large, the outer 

circle having a diameter of from .020mm to ,025mm, and the inner of from 

.005mm to .008mm. The walls of the medullary rays are marked by large 

oval pores, from one to three of which occupy the width of a single 

wood cell. These pores are about .015mm in length and .010mm in the 

short diameter. The resin ducts consist of a chain of short, small, 

thin walled cells, which now contain a small quantity of granular 

matter, representing probably the drops of resin. The individual cells 

have a length of from .12mm to .25mm and a diameter of about .05mm, 

slightly less, it will be observed, than the trache'ids among which they 

run.

Tangential section: The medullary rays aie always simple; that is, 

they consist of but a single row of cells, which varies from 2 to 49 cells 

in height. The trache'ids are provided on the tangential walls with a 

few scattered bordered pits. These have a diameter of from .016mm to 

.021""".

This species, which I take pleasure in naming in honor of the collector, shows remarkable affinities with several species that have been 

described by Mercklin from the Tertiary of Eussia. So close, indeed, 

is the resemblance that I was at first inclined to describe it under 

one of Mercklin's names, but a more careful examination has shown 

points of difference which seem to entitle it to specific rank. Thus C. 

sequoianum Mercklin, which has been reduced to a synonym of C.pannonicum by Felix (Die Holzopale Ungarns, 1884, p. 36), differs in size 

of the trache'ids and in the size and shape of the pits on the radial 

walls. The ray cells are also unlike in shape, arid they differ in the 

number of cells that compose them. In C. erraticum and its variety 

Teredinum of Mercklin (Palaeodendrol. ross., pp. 60-63, pi. xiv and xv) 

the individual resin cells are much larger and not at all constricted at 

the ends. The trache'ids are smaller and mostly provided with one and 

more than two rows of bordered pits, The pits on the walls of the
48 FOSSIL WOOD AND LIGNITE. IBULL. 56.

medullary rays also differ in size and shape. There are also points of 

resemblance with C. nodosum Goppert (Mon. foss. Conif., p. 203, pi. 

xxviii, figs. 1-4) and Pence (Cupressinoxylon?) affinis linger (Ohlor. 

prot., p. 30), but they are more remote and hardly worth consideration. 

Besides these variations in anatomic features there still remains the 

greater one of the difference in geologic horizon. C. McGeei comes from 

the Jurassic or the very lowest Cretaceous, while all of the above species are found in the Tertiary, and Kraus has given as his opinion that 

species can be very rarely traced from one formation to another without

changes in form. 1

CUPRESSINOXYLON WARDI, u. sp.

PI. IV, Figs. 1-4 ; PI. V, Figs. 1, 2.

Description. Annual ring distinct, moderately broad ; trache'ids medium in size, the radial walls bearing one, rarely two, rows of bordered 

pits ; medullary rays two cells broad and from .one to thirty-five cells 

high ; resin ducts simple, not numerous.

This species is represented by specimens from the localities which 

have been designated by the letters A and B, respectively.

A. Several small fragments collected by W. J. McGee in a cut on the 

Washington Branch of the Baltimore and Ohio Eailroad about half way 

between Montello and Kives Station, D. C. The largest piece is only 

8cra long, 6cm wide, and lcm thick, and the others are much smaller. 

They are all very poorly preserved, and the structure can be made out 

only in a few favored spots.

B. A small piece, hardly 5cm square, collected by Lester F. Ward from 

Freestone Out, on the Neabsco Creek, Virginia. Like the other specimens, this is very badly preserved, and the structure. has entirely disappeared in many places.

The specimens from both localities are yellow in color, and have the.

cavitie.s in them filled with minute quartz crystals.

Microscopic analysis. Transverse section : The fragments are all too 

small and too poorly preserved to show the annual rings to the naked 

eye, but under the microscope they are observed to be tolerably distinct. The ring of fall wood consists of from three to six or eight compressed cells in each radial row. The spring wood contains some very 

large cells, with a diameter in some instances of .062mm. The number of 

cells in each row of trache'ids varies according to the width of the annual ring, there being frequently as many as one hundred. Large intercellular spaces occur particularly where additional rows of trache'ids 

have been introduced.

Eadial section : In this section the trache'ids are shown to be provided with one row, or, in some rare instances, with two longitudinal 

rows of bordered pits. They occupy the center of the cell and are close 

together, almost touching in some cases. The larger have a diameter

JR Traits-Pal- Y%-, W, P, Semper, Vpl, 3, j>
KNOWLTON.] DESCRIPTION OF SILICIFIED SPECIES. 49

of .020mra, and the smaller a diameter of .015mm. The medullary rays 

consist of typical parenchyinatous tissue. The individual cells are 

short, covering the width of from four to eight trache'ids. I have not 

been able to detect markings on the walls of the rays, but this may be 

on account of the poor state of preservation of the specimens. The 

resin ducts are not numerous. They are of nearly the same size and 

shape as the trache'ids, and in fact look very much like trachei'ds with 

transverse partitions. They are almost always empty.

Tangential section: The trache'ids are not provided with pits on the 

tangential walls, or at least none have been detected. The medullary 

rays in many cases are two cells broad, and, as above indicated, from 

one to thirty-five cells high. The individual cells of the rays have a 

diameter of from .017mm to .030mm.

This species I take pleasure in naming in honor of Prof. Lester 

F. Ward, who collected the specimen from Neabsco Creek. It has, 

like the others, affinities with several described species, but the resemblances are too vague to suggest specific identity.

CUPRESSINOXYLON COLUMBIANUM, D. 8p.

PI. IV, Fig. 5; PI. V, Figs. 3, 4; PI. VI, Figs. 1-5; PI. VII, Fig. 1.

Description. Annual ring very broad, indistinct5 trachei'ds very 

thick walled, provided with one or two rolls of small pits; medullary 

rays consisting of one layer of small, thick walled cells, ranging from 

three to forty cells in height; resin ducts numerous, of a chain of short 

but thick walled cells.

This species is also represented by specimens from two localities.

C. A piece 15cm long, 10cm wide, and 5cm thick, collected by W! J. 

McGee at the Dutch Gap Canal on the James River, about twenty miles 

below Kichmond, Va.

D. Several larger pieces, some of them 25cm long, collected by Prof. 

William M. Fontaine, of the University of Virginia, from, "sandy clay, 

a little north of Mr. Kankey's house, near Neabsco Creek, Virginia." 

The specimens from both localities have been severely crushed by pressure and in places are much distorted. They are grayish in color, 

marked in places by streaks of black.

Microscopic analysis. Transverse section: The annual ring is very 

indistinct, although not entirely absent, as I have observed slight traces 

of it among a mass of crushed cells. The trache'ids are arranged in 

very regular radial rows, and are remarkable for their nearly uniform ' 

size and thick walls. The larger cells are about .050mm in diameter, 

the smaller from .030mm to .(MO 111 in diameter. The medullary rays are 

not abundant and appear very narrow as seen in this section.

Eadial section: The trache'ids are here seen to be thick walled and 

to be covered with one or rarely two rows of bordered pits, which are 

rather small. The larger pits have a diameter of .Q15mm and the smaller 

Bull. 56 4
50 FOSSIL WOOD AND LIGNITE. IBULL. 56.

a diameter of only .010mm. The rays consist of long cells, in some cases 

provided with minute round punctations. Thus the specimen from 

Dutch Gap exhibits them in places, but the Keabsco Creek specimens 

show but slight traces of them. The resin ducts are numerous, two of 

them appearing side by side in a single figure (PL VI, Fig. 2). In 

most cases they consist of a regular chain of short cells constricted at 

the joints. The cells of the specimen from Dutch Gap are filled with a 

multitude of minute round globules. In the other specimen they are 

nearly empty.

Tangential section: The medullary rays are shown to have very small 

cells which have a long diameter of from .015mm to .017mm and a short 

diameter of only .010mm ; the walls of the tracheids are so thick and the 

rays so small that the walls between which they appear are but slightly 

"bulged." The tracheids do not exhibit pits on the tangential walls.

There are resemblances between this species and several other described species, but they are not of sufficient importance to require extended consideration, particularly as they occur in widely separated 

geologic and geographic positions.

ARAUCARIOXYLON Kraus.

Araucarioxylon Kraus, 1870-72. lu Trait6 Pal. V6g., W. P. Scaimper, vol. 2, p. 380.

Araucarites Presl., 1820-'38. In Stemberg's Vers., vol. 2, p. 203.

Pinites Witham, 1833. Int. Struct., Foss. Veg., etc., p. 72.

Dadoxylon Endlicker, 1847. Synop. Conif., p. 298.

Pissadendron Endlicher, 1842. Gen. Plant. Suppl., vol. 2, p. 27.

Palceoxylon Brongniart, 1849. Tableau des genres de ve"g6taux fossiles, p. 77.

ARAUCARIOXYLON VIRGINIANUM U. 8p.

Plate VII, Figs. 2-5.

' Description. Annual ring very indistinct, about 2mm broad; tracheids 

bearing one or two rows of hexagonal pits on the radial walls; medullary 

rays simple, of from 1 to 27 superimposed cells; resin ducts none.

This species, the only one of the genus that has been found in the 

Potomac formation, was collected by W. J. McGee, at Taylorsville, Va, 

It is a small piece, only about 10cm long and 6cm square, and is grayish 

in color. The structure is very well preserved, although somewhat 

disorganized in places by the process of silicification.

Microscopic analysis. Transverse section: The annual ring is not perceptible to the naked eye, but when a thin section is examined under 

the microscope it is observed to be present. The actual ring or line of 

demarkation between the layers consists of only three or four rows of 

slightly smaller an$ thicker walled cells. In the living species of Araucaria the annual ring is usually indistinct and not infrequently entirely 

absent, both conditions sometimes obtaining in different parts of the 

same plant.

The tracheids are prominent and have rather thick walls, The indi-
KKOWLTOH.J DESCKIPTION OF SILICIFIED SPECIES. 51

vidual cells have a diameter in some instances of .051mm, the average 

being perhaps .0375mra . They are arranged in radial rows, which are 

most pronounced in proximity to the medullary rays. In places when 

additional layers of cells have been intercalated, considerable intercellular spaces have been left that are now filled with nearly transparent 

silica.

Eadial section: The radial walls are the only ones observed to bear 

bordered pits. The number of rows vary, even on the same cell, from 

one to two. When there is but one row they occupy the center of the 

cell and are in contact. They are then nearly circular in outline, and 

have a diameter of from .017m to .020mm. When there are two rows 

they are in contact and alternate with each other, and have a nearly 

regular hexagonal outline. These hexagonal pits have a diameter of 

from .016mm to .021mm. The inner pore is very small, being only about 

,0025mm to ,0030mm in diameter.

Tangential section: The rays as seen in transverse section are shown 

to be single and to range from one to twenty-seven cells in height, the 

average number being about ten or twelve.

There have been thus far about forty species characterized from the 

wood which are now referred to the genus Araucarioxylon. This genus, 

as now emended, is of very great antiquity, having had its origin in the 

Middle Devonian, from which Dawson has described five species in this 

country, and has continued uninterruptedly to the Lower Miocene, from 

which several species are known. The living species, which show remarkable affinities with some of the fossil forms, are undoubtedly the 

lineal descendants of the ancient line. The antiquity is further confirmed by the number of species that have been described from leaf or 

cone impressions. According to Zincken, thirty-eight species have been 

reported from below the Carboniferous, forty-two from the Carboniferous 

proper, ten from the Triassic, eighteen from the Jurassic, ten from tne 

Cretaceous, and one from the Tertiary. Some of these latter species 

may represent the branches or cones of some of the forms described 

from the wood alone, but we are at present unable to correlate them, and 

probably shall always remain so. It would be very satisfactory if we 

could correlate many of these supposed identical forms, for by so doing 

the number of paleontologic criteria would be reduced, and their value 

as stratigraphic marks proportionately enhanced. However, we must 

take them as they are and look to more careful research in the future 

to supply, if possible, the links.

In indicating that the above species is new to science I have followed 

the method of exclusion adopted by Beust in his admirable paper on the 

Fossil wood of Greenland.

Taking the markings on the wood cells and the height and the breadth 

of the medullary rays as the most important diagnostic characters, an 

examination of the described species gives the following results;
52 FOSSIL WOOD AND LIGNITE. [BULL. 56.

Species which have but one longitudinal row of bordered pits:

Araucarites Edwardianus Gopp. Araucarites orientalis Gopp.

Araucarites Eeuperianus Gopp. Araucarites Iriarmicus Kut.

Araucarites stellaris Gopp. Araucarioxylon Schmidianum Fel.

Araucarites Schrollianus Gopp. Dadoxylon sulrhodeanum Grand'Eury.

Species bearing from two to three rows:

Araucarites Itollei Gopp. Araucarites carbonaceus Gopp. 

Araucarites Valdejolensis Mougeot. Araucarites argillicola Eichw. 

Araucarites subtilis Mercklin. Dadoxylon annulatum Daweon. 

Araucarites materiarum Gopp. Dadoxylon antiquius Dawson. ' 

Araucarites Brandlingi Gopp.

Species having one to three or more rows:

Araucarites JEgyptiacus Gopp. Araucarites ambiguus Gopp. 

Araucarites Saxonicus Gopp. Araucarites Eicliteri Gopp. 

Araucarites medullaris Gopp. Araucarites pachytichus Gopp. 

Araucarites cupreus Gopp. Araucarites Stigmolithots Gopp. 

Araucarites permicus Mercklin. Dadoxylon intermedium Grand'Eury. 

Araucarites lieinertianus Gopp. Pitys With, et Lindl. 

Araucarites Tchihatcheffianus Gopp. 

Araucarites acadianus Gopp [Dadoxylon 

Dawson].

It now remains to examine such as have from one to two rows of bordered pits, and to show the points of variation between them and the 

Potomac species:

Araucarites Kutorgce Mercklin From the Permian of Russia. The medullary rays 

consist of from 4 to 15 cells.

Araucarites vogesiacus Gopp. From the Lower Carboniferous of Niederburbach. Cells 

of the ray from 1 to 20.

Araucarites stephanense Grand 'Eury. From the Carboniferous of France. This species has the rays only 1 to 3 cells high.

Araucarioxylon Heerii Beust. From the Lower Miocene of Greenland. Ray cells from 

1 to 82 in number.

Araucarioxylon Rhotieamim Gopp. From the Permian of Silesia. The rays are composed of two rows of cells.

It will be observed from this list that the species with which our plant 

shows the greatest affinity are all from the Carboniferous or the Permian of Europe; but it would be unreasonable to suppose, provided the 

identity was close, that any of thenv had continued unchanged from the 

Carboniferous to the Potomac formation, for, as before stated, species 

rarely pass unchanged from one formation to another.

These considerations teach us that the species under discussion differs in essential points from any that have heretofore been described. 

I have named it Araucarioxylon Virginianum, from the State in which it 

was obtained.
PLATES.

53

PLATE I.

55
PLATE I.

FIGS. 1-5. Lignite.

FIG. 1. From the new reservoir, Washington.

Tangential section, a, a, a, cells of medullary rays filled with hard, black

substance. X 67. 

FIG. 2. From the new reservoir, Washington.

Transverse section, a, distorted medullary ray. X 242. 

FIG. 3. From the new ressrvoir, Washington.

Radial section, a, bordered pit on well-preserved tracheld; 6, two small pits

on medullary ray. x 242. 

FIG. 4. Source unknown.

Tangential section, showing two badly crashed and distorted medullary rays.

X 242. 

FIG. 5. From Neabsco Creek, Va.

Natural size, a, annual rings; 6, t'races of medullary rays; c,surface exhibiting conchoidal fracture and no trace of structure.

56
U. S. GEOLOGICAL SURVE* BULLETIN NO. 56 PL.

tj {«' 5 !.?«

'Sj!, if!

0 d o 0 I 0 o 0 I nn ou»Uy

I 

...a
PLATE II.

57
PLATE II.

FIGS. 1-4. Cupresainoxylonpulchellum, n. sp. From Spring Hill, on Appomattox River 

Va.

FIG. 1. Radial section, a, a, resin-ducts ; 6, &, medullary rays. X 67. 

FIG. 2. Transverse section, a, a, medullary rays: b, fall wood; c, spring wood.

X 67. 

FIG. 3. Transverse section of pith, a, a, cells of pith; 6, b, medullary rays; c,

tracheids in contact with pith, x 67.

FIG. 4. Tangential section, a, medullary ray of single cell. X 67. 

FIG. 5. Cupressinoxylon McG-eei, n. sp. From the new reservoir, Washington, D. C. 

' Radial section, a, point at which the structure has disappeared; 6, b, medullary 

rays, mostly showing oblong pores, x 67.

58
U. S. GEOLOGICAL SURVEY BULLETIN NO. 56 PL. II

3.

4. 5.
PLATE III.

59
PLATE III.

FIGS. 1-5. Cupressinoxylon McGeel, n. sp. From the new reservoir, Washington, D. C. 

FIG. 1. Transverse section showing annual ring, a, cells of fall wood; &, typical

cell of spring wood; c, large intercellular space; d, d, smaller intercellular

spaces. X 67. 

FIG. 2. Tangential section, a. resin-duct: b, b, bordered pits on tangential walla;

c, sections of pits on radial walls, x 67. 

FIG. 3. Eadial section. Same section as Fig. 5, PI. II. X 242. a, a, pits on

walls of medullary rays; &, Z», pits on walls of tracheids. 

FIG. 4. Transverse section further enlarged, a, medullary ray; 6, Z>, cells of spring

wood; c, section of pits on radial walls; d, section of pits on tangential wall.

X 242. 

FIG. 5. Tangential section, a, resin-duct; Z), ft, bordered pits on tracheids; c, o,

bordered pits on resin-duct connected by spiral lines.

60
U. S. GEOLOGICAL SURVEY BULLETIN NO. 56 PL. Ill
PLATE IT.

61
PLATE IV.

FIGS. 1-4. Cupressinoxylon Wardi, n. sp.

FIG. 1. From Neabsco Creek, Va. Transverse section through annual ring, o, 

cells of fall wood; Z», cells of spring wood; c, c, c, large intercellular spaces. 

X67.

FIG. 2. From cut on B. & O. R. R. Tangential section. a? resin-duct; b, medullary two cells broad. X 67.

FIG. 3. From cut on B. & O. R. R. Radial section, a, a, medullary rays; ft, 

single row of pits on trache'ids. X 67.

FIG. 4. From cutou B. & 0. R. R.- Transverse section further enlarged, a, cells 

of small annual ring; &, medullary ray; c, hexagonal cavity iu the silica which 

fills the cell, x 242. 

FIG. 5. CupressinoxyJon Columbianum, n. sp.

From Neabsco Creek, Va. Transverse section showing resin-duct, a. x 242.
U. S. GEOLOGICAL SURVEY BULLETIN NO. 56 PL. IV

3.
PLATE V.
PLATE V.

FIGS. 1, 2. GupYessinoxylon Wardi, n. sp.

FIG. 1. From cut on B. & O. E. E. Transverse section through annual ring.

a, cells of i'all wood; b, I, 1), medullary rays; c, very large intercellular space. X 67* 

FIG. 2. From Neabsco Creek, Va. Eadial section, a, medullary ray; 6, tracheicl

with two rows of bordered pits. X 67. 

FiGS. 3, 4, Cupresslnoxylon Columlriamim, u. sp.

FIG. 3. From Neabsco Creek, Va. Eadial section, a, resin-duct; 6, 1), medullary

rays. X 67. 

FlG. 4. From Dutch Gap Canal, Va. Tangential section. X 67.

64
U. S. GEOLOGICAL SURVEY BULLETIN NO. 56 PL. V

4.
PLATE VI

Ball. 56 5 65
PLATE VI,

FIGS. 1-5. Cupressinoxylon Columbianum, ti. sp. From Dutch Gap Canal, Va.

FIG. 1. Transverse section, a, a, medullary rays; Z>, typical trache'ids. x 67.

FIG. 2. Radial section, a, a, resin-ducts; &, 6, medullary rays. X 67.

FIG. 3. Transverse section further enlarged, o, medullary ray; 6, 5, typical cells

of spring wood. X 242.

FIG. 4. Transverse section of resin-duct, a. x 242. 

FIG. 5. Radial section further enlarged, a, cell of resin-duct filled with minute

globules of resin; Z>, tracheld with a single row of bordered pits; c, tracheld

with two rows of bordered pits. X 242.

66
U. S. GEOLOGICAL SURVEY BULLETIN NO. 68 PL, VI

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PLATE VII.

67
PLATE VII.

FIG. 1. Cupressinoxylon Golumbianum, n. sp. From Neabsco Creek, Va.

Tangential section. X 67. 

FIGS. 2-5. Araucarioxylon Virginianum, n. sp. From Tayloraville, Va.

FIG. 2. Radial section, a, a, medullary rays; ft, tracheids with two rows of

hexagonal pits; c, walls of tracheids dislocated by pressure. X 67. 

FIG. 3. Transverse section, a, a, a, medullary rays; fc, 6, intercellular spaces..

X 67.

FIG. 4. Tangential section, a, sections of bordered pits on radial walls. X 67i 

FIG. 5. Radial section further enlarged, a, single row of rounded pits; l», double 

row of hexagonal pits. X 242.

68
U. S. GEOLOGICAL SURVEY BULLETIN NO. 56 PL. VII
INDEX.

A.

Page. 

Abies............. ............................................ 14

Acacioxylon ............................................... 35

Acerinum................................................... 20

Agricola, early mention of fossil wood by.. 13

Alaska, fossil wood from ........................... 37

Albinius, description of fossil birch by......' 13

Alnoxylon............................................... .. 35

Anabathra, first mention of......................... 17

Anacardioxylon .......... .............................. 34

Ancients, knowledge of, concerning fossil 

wood........................................................ 12

Antigua, fossil wood from.......................15,33,34

Aporoxylon ....................................... 23,24,25,33

Araucaria................................................... 19

Araucarioxylon.......................................... 28,35

affinities of.......................... 35,50

Heerii............ ................... 35

Virginianutn, n.sp............ 5O

Araucarites ...... ........................................... 21,26

Mollhausianus.......................... 23

Schrollianus ............................. 25

Aristotle, generatio sequivoca of................ 14

Arundo........................................................ 24

Australia, fossil wood from......................... 33

Avicenna, vis lapidiflca of......... ........ ......... 14

B.

Bailey, J. W., on fossil wood from PosunculaRiver................ ................................ 23

Balbinius, description of specimens by...... 13

Balfour, J. H., on coal of Fordel............... 22

Beck, Richard, on Oligocene from Mittweida............................... 33

paper by........................... 37

Benney, E. W., on coal plants of England.. 27 

on structure of Carboniferous plants ....................... 30

Betula....................................................... 54

lignitum............. ...............>............... 27

MacClintockii................................... 28

Betuliniurn...... ....... ................................... 20,24

Betuloxylon................................................ 36

Beust, Fritz, on fossil wood of Greenland.. 35 

Blanckenhorn, Max, paper by ............. .... 37

Boyle, on process of fossilization .............. 13

Bradtea........................................................ 22

Brazil, fossil wood from ............................. 33

Bromel, on process of fossilization.......!.... 13

Brongniart, on Sigillaria elegans............... 18

Bronn, Heinrich Georg, papers by ............ gl

C.

Page.

Catamites ................................. ................ 31

Calamodendron.......................................... 31

Calamopitys ............................................... 23

Calamopteris............................................. 23

Capparidoxylon ......... ....................... 35

Carruthers, William, on Cycadean stems

of Britain.............. .28

on petrified forest 

near Cairo............ 29

Cassioxylon................................................ 34

Cedroxylon ................................................ 28,30

Cladocupressoxylon Protolarix................. 33

Cladoxylon ............................................... 23

Claypole.E. W., on fossil wood from Carboniferous of Ohio......... 37

on fossil tree from Ohio ... 31 

Clethrites ................................................... 13

Colopoxylon............................................... 26

Constantiniutn............ ............................... 27

Comvgntz, H., on Calistoga fossil wood..... 29

on fossil wood from Patagonia .............. ............... 36

on fossil wood of Berlin 

land office....................... 32

on fossil wood of Karlsdorf 32 

on the petrified wood of the

North German Diluvium 31 

Copper Island, fossil wood from................. 37

Corda, August Joseph, "Flora der Vorwelt" ....................................................... 19

Cormocupressoxylon Protolarix ............... 33

Cornoxy Ion................................................ 32

Cotta, C. Bernhard, "Die" Dendrolithen".. 17 

Cratner, C., fossil wood of Arctic- Zone...... 27

Cuba, fossil wood from .............................. 33

Cupressinoxylon......................................... 21, 27

affinities of....................35,36,43

Breverni........... ............... 2S

Columbianum, n. sp......... 49

definition of..................... 44

dubium............................. 2&

erraticum ........................ 37

glyptostrobinum.............. 35

McGeei, n. sp .................. 46

Mercklini ........................ 36

polyommatum ................. 28

Protolarix........................ 33

pulcellum, n. sp.............. 45

pulchrum ........................ 28

taxodioides................. ... 29
70 INDEX.

Page.

Cupressinoxylonuniradiatutn.................... 32

ucranicum....................... 28

Wardi, n. sp.................... 48

Cupressoxylon.. ..............:.......................... 28,30

D.

Dadoxylon..................:.......................... .25,26,33

from Prince Edward Island...... 22

antiquius ................................... 37

Edvardianum .......................... 30

tnateriarium............................. 30

Newberryi................................ 37

Dakota, fossil wood from........................... 37

Dalmatia, plant beds of.............................. 12

Dawson, J. W., Devonian and Carboniferous plants....................... 25

flora of the Devonian......... 25

fossil wood from Gasp6..... 23

fossil wood from Prince 

Edward Island............... 22

on affinities of Sigillaria 

Catamites and Calamodendron.......................... 30

on plants of Brian and Silurian formations........... 33

on plants of Gaspe.............. 24

on plants from lignitic tertiary................................ 30

pre-Carboniferous flora..... 25

synopsis of Carboniferous 

flora in Nova Scotia........ 26

vegetable structures in 

coal................................. 24

Diploxylon ................................................ 27

Dornbeyoxylon ........................................?. 35

Dryites .................. .................................... 13

E.,

Ebenoxylon................. .............................. 34

Ebony, fossil............................................... 13

Egypt, fossil forests of................................ 13

fossil wood from ............................. 18

Eichwald, Edouard D', paleontology of

 Russia............................ ......................... 27

Elatites ...................................................... 13

Endlicher, Stephen, " Synopsis Coniferarum^'....................................................... 20

Endogenites ............................................... 16

Ephedra.......................................... ........... 19

F.

Fasciculites................................................ 32

Fegonium............................................... ... 20

Felix, Johannes, examinations of fossil

wood ............................ 34,36

fossil wood of West Indies................................ 34

on fossil coniferous wood. 33 

on wood opal of Hungary. 35 

studies on fossil wood..... 32

Ficoxylon .................. ................................ 34,35

Fontaine, William M., on age of Potomac 

formation................................................ 38

Fungus, mycelium of,fossil ....................... 32

G.

Gazlay, Eev. Sayrs, papers by.................... 18

Gesner, description of specimens by......... 13

Glyptostroboxylon .................................... 36

Goldenberg, Friedrich, on Sigillarieto and 

Selaginese................................................. 23

Good Hope, Cape of, fossil wood from ...... 18

G6ppert,H. K.,amber flora......................... 19

first genus of dicotyledons 

founded by..................... 19

" Flora der Gypsformation"............................... 19

" Flora des Uebergangsgebirges " .......................... 21

flora of Achen .................. 19

flora of the Permian......... 25

monograph of the Coniferae...................... 12,20

19

23

19

22

21

on fossil Cycadacese .........

on fossil wood from New 

Mexico.................... ......

on Taxites scalariformis...

on Tertiary flora of Java..

on Tertiary flora of Silesia

Goppert, H. E., and Menge, A., flora of the

amber...................................................... 34

Goppert, H. K., and Stenzel, C. G., on Meduloseae.................................................. 32

H. 

Hauera........................................................ 24

Americana ............ ....................... 24

Helictoxylon.......... ......... .......................... 34

Henkel, early work by.............................. 15

Hildebrand, F., on distribution of Coniferas 25 

Hire, de la, description of specimens by ... 14 

Hitchcock, Edward, brown coal of Brandon, Vt..................................................... 21

Hofmann, H., works by ............................. 36

Holmes, W. H., on fossil forest of Yellowstone Park............................................... 29

Hook, Robert, description of specimens by 13 

Hooker, J. D., on structure of Lepidostrobi 28 

on structure of Stigmaria... 28 

Hutton. (See Lindley & Hutton.)

I.

Imperatus, on process of fossilization........

India, fossil wood from..... ........................

Internal structure, value of study of.........

13 

33 

11 

Italy,plant beds of...................... ............... 12

J.

Japan, fossil wood from ..... ....................... 33

Java, fossil wood from................................ 33

John, J. F., origin and nature of amber ... 16

Jordania ..................................................... 35

Junghuhnites............................................. 22

K.

Kentmann, on process for producing fossils artificially.......................................... 13

Kieser, on organization of plants .............. 15

Klippsteinia ............................................... 24
INDEX. 71

Klcedenia quercoides ................................ 19

Kraus, Gregor, "Araucarien d. Rothliegenden "............. ......... 27

" bayrische Tertiarholzer" .............................

fossil Coniferse ...............

on structure of living and 

fossil Conifene..............

Kutorga, S., paleontology of Russia .........

L. 

Laurinium Meyeri...................................... 37

Laurinoxylon...................... ....................... 34,35

Lepidodendron ...................................17, 23,24,31

Lepidostrobus............................................ 31

Lesquereux, Leo, on fossil fruits of Brandon, Vt.....................................................

Lhwyd, Edward, first use of term Lithoxylon .........................................................

Libocedrus Sabiniana................................. 35

Lignite, occurrence of ......... ..................

preparation of, for study............... 40

systematic description of..............

Lillia ...........................................................

Lindley & Hutton, " Fossil Flora of Great 

Britain"..................................................

Liquidalnbaroxylon ................................... 35

Lithoxylon.................................................. 14,15

Little Missouri, fossil wood from...........

Luther, Martin .flood theory of.................. 14

M.

Magnus, Albertus, earliest account of petrified wood by..............

virtus formativa of ......

Malpighi, discovery of pits on wood cells 

of conifers by................................... .....

Marsh. O. C., on ageof Potomac formation 

on fossil forest in California.. 

Martin, William, early work by.................. 15

Massalongo,on fossil palms...................... 21

Matthiolus, early description of specimens

by.

McGee, W J, on ageof Potomac formation..

on composition of Potomac

formation ............................

Medullose...................................................

Mercklin, C. von, on fossil wood and amber .................... .....................................

Miquelites...................................................

Morton, John, description of specimens by 

Mull,fossil wood from island of.................

Myelopitys.............................. ..................

N.

Negro Island, fossil wood from.. .... ...........

New Guinea,fossil wood from .................. . 37

Nicol, William, observations on conifers... 

Nicolia........................................................

. ^Egyptiaca ...................................... 23, 27

Owenii.............................................

Zelandica.........................................

Noggerath, Jakob, Carboniferous fossils... 

Nubia.fossil wood from.............................. 18

Nymphsea...............................................

ge19

27

27

28

26 

19

37

,35 

,31

31

22

14 

35

40

40

11

34

17

35.

,15

37

14

14

16

oo

15

21

1 Q

00

OQ

26

91

00

I 0

26

37

37

18

35

,27 

29 

25 

16

i s

?4

O.

] 

Organic remains, kinds of, in Potomac formode of occurrence of...

P.

Paleobotany, lines of investigation folvalue of, to stratigraphy.......

Petrified wood, earliest published accounts 

of..............................................................

Pitus..... ......................................................

 geological and geographical disQ.

O.uercus.. ....................................................

Page. 

40

39 

14

11

11

11

11 

33,34

17

17

33

33

10

17,24

19

19

13

37

21

21,26

17

19

19

18

28

19

81

28

33

20

18

14, 19

32

OQ

21

17

28,30

37

37

36

20

25

30

38

39

40

38

21

25,33

15

22,26

24

31,34

31

H
INDEX.

B.

Page. 

Renault, B.., on Sigillaria spinulosa.... ...... 31

oti stems of the Carboniferous....................................... 31

on structure of Asteromyelon.. 36 

Rhizoalnoxylon ........................................ 32

Rhizocupressinoxylon................................ 32,34

Protolarix............... 33

Rhizonium.........*......................................... 3-1

Rhode, on fossil wood ................................ 16

Richter & Unger, "Paleontology of the 

Thuringian Forest" ................................ 23

Rogers, W. B., on the Potoniac formation.. 38

 Rohlfsia...................................................... 34

Roman Empire, plant-beds of .................... 12

Roque, Abbe de la, description of specimens by .................................................. 14

S.

 Sapotoxylon............................................... 34

Schaefler, George C., fossil wood from the 

Colorado Desert ...................................... 22

'Schenk, A., on Cotta's species of Perfossus.. 83 

on fossil wood from India........ 33

on fossil wood of the Libyan . 

Desert................................... 34

'Scheuchzer, Johann Jacob, "Herbarium 

Diluvianum"........................................... 14

 Schlotheirn, B. F. von, on fossil wood........ 16

Schmalhausen, J., on Tertiary flora of 

Russia...................................................... 36

 Schmid & Schleiden, " Natur der Kieselholzer" ................................................... ' 22,

 Schmideliopsis............................................ 34

Schroter, J. S., early work by..................... 15

Schroeter, Carl- on Arctic fossil wood........ 31

Sequoia ............ ......................................... 36

Sigillaria..................................................24,27,31

elegans.......................................... 18

 Silicified wood, occurrence of, in Potomac

formation....................... 40

preparation for study of... 40 

systematic description of,

from Potomac formation 41 

Solms-Laubach, works by........................... 36

Spiropitys................................................... 21

Sprengel, Anton, work on Psarolithes...... 16

Stelachites........ ......................................... 13

Stelluti, Franciscus, first book devoted to 

fossil wood............................................... 13

 Stenzel, C. G., on fossil palms............. ...... 21

"Staarsteine"..................... 22

Stenzelia..................................................... 26

Staubia........................................................ 35

Sternbergia ................................................ 25

Stigmaria........................................... ....23,24,31

Syringoxylon .................................... ........ 25

T.

Taenioxylon.

eperuoides.

.................... 34

37 

Taxites............................. .......................... 21

Taxoxylon.................................................. 28,30

Taxus ........................ ........... .................... 19

Tchihatcheffltes.......................................... 27

Thuioxylon................................................ 24

U. 

Ulminium.................................................. 20

Ulodendron................................................ 24

Unger, Franz, " Chloris protogsea"........... 20

Flora of Gleichenberg...... 22

fossil forest near Cairo..... 23

fossil plants from New 

Zealand........................ 25

" Genera et species plantarum fossilium "......... 20

synopsis of fossil plants... 19

V.

Vater, H., works by ................................... 36

Voigt, Johann K. W., description of Psarolithes by.................................. .............. 15

Volkmann, Georg Anton, early work by... 15

W.

15

12

Walch, early work by ...............................

Ward, Lester F., "Sketch of Paleobotany " ......................................................

Weber, C. Otto, on Tertiary flora of the

Lower Rhine............................................ 21

Weppen, J. A., work by............................. 15

West Indies, fossil wood of........................ 34

Westphal, description of specimens by...... 14

Williamson, "\V. C., list of principal works

by......'....................... 29

on organization of fossil plants of the Coal 

Measures.................. 29,37

on value of evidence 

obtained from internal structure............ 12

Witham, Henry T. M., works by............... 16

Worman, description of specimens by....... 13

Z.

Zamites. 

Zittelia..,

26

34