REVIEWS

THREE PHASES OF MODERN PALEONTOLOGY

I. Uintacrinus: Its Structure and Relations. By FRANK SPRINGER. (Mem. Mus. Comp. Zoöl., Vol. XXV, pp. 1-90, 8 pls., Cambridge, 1901.)

II. Oriskany Fauna of Becraft Mountain. By JOHN M. CLArke. (Mem. New York State Mus., Vol. III, No. 3, 128 pp., 9 pls., Albany, 1900.)

III. Stratigraphical Succession of the Fossil Floras of the Pottsville Formation in the Southern Anthracite Coal Field. By DAVID WHITE. (U. S. Geol. Surv., Twentieth Ann. Rept., Part II, pp. 749-930, 13 pls., Washington, 1901.)

Three notable contributions to our knowledge of fossil organisms have lately appeared from the hands of the printer. They are notable as making distinct advancements in paleontology. They are notable as typifying the three distinct phases into which the science relating to ancient life has finally resolved itself. They are notable as model works of their kind, each representing the general subject from a very different viewpoint, and hence show very diverse modes of treatment and the very diverse character of paleontological inquiry of today.

1. The crinoids have long been an attractive theme to geologists. Ever since the discovery by Marsh, in 1870, of the remarkable Cretaceous crinoid afterward called Uintacrinus, great interest has been taken by paleontologists in each new accession. Grinnell, Meek, Willison & Hill, and Logan, in this country, and in Europe, Schlüter and Bather, have described carefully the known material. It has remained for Mr. Springer, so long intimately associated with the lamented Wachsmuth, to give us a magnificent monograph on the subject, including a large amount of new information derived from rich, lately discovered material. And this after one would naturally think that about all that it was possible to say had been said.

The special charm and value in this work is the strictly morphological character that it presents. In this respect it fully keeps up the

same high standard of excellence that made the North American Crinoidea Camerata of Wachsmuth & Springer so acceptable to all students of fossil organisms.

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Unusual interest centers in the composition of the base of UintaA feature that has long been regarded as fundamental in the separation of the larger taxonomic groups is here found in one and the same species. Considering the apparent identity of these forms in every other point of structure, coupled with their mode of occurrence and association, I do not see how such association [as made by Mr. Bather] can possibly be made in this case. We therefore have apparently to deal with a case of individual variation as to this supposed primitive character, within the limits of a species. That is to say, in this species, living in the same locality, having the same. environment, floating in the same mass, certain individuals matured to represent one stage of larval development, i. e., with infrabasals; and others in another stage, i. e., with basals only.

In short, there are the two supposed distinct types, Monocyclica and Dicyclica, occurring in both young and adult of one and the same species. It will not do to say that the species is dicyclic, but in certain individuals the infrabasals are not developed, or are hidden by the centrale, or have disappeared by atrophy, If this were so, the centrale ought to be interradial in both cases; whereas, as already shown, its orientation is reversed from one to the other, precisely as in the typical monocyclic and dicyclic forms.

Such a condition is believed to be unique among the crinoids. The bearing upon certain recently proposed classifications of the crinoids is also important. Bather and Jaekel have both severely criticised Wachsmuth & Springer's classification and have erected schemes that are "sought by the modern biologist."

"There is no doubt," says Mr. Springer, "that each author who undertakes to express his ideas of descent in a new scheme of classification does so in the belief that his own structure is a substantial pyramid whose base is firmly established upon the ruins of the topheavy contrivances of his predecessors. With regard to the crinoids, there have appeared, since our monograph of the Camerata, two elaborate classifications, each avowedly based upon phylogenetic principles, viz., that of Mr. Bather, already mentioned, and one by Dr. Jaekel, whose general researches and great works upon the crinoids of Germany constitute a rich contribution to science. The views of the latter author are to be developed in full detail in his magnificent

"Stammesgeschichte der Pelmatozoen," the first part of which, embracing the Thecoidea and Cystoidea, has just been published. He, likewise, finds fault with Wachsmuth & Springer, because, in his opinion, they have dealt with the morphological conditions as they found them too much from an anatomical standpoint, and have not sufficiently taken into account the import of the modifications due to descent. He finds in the changes in the systematic arrangement of the crinoids made by Wachsmuth & Springer in their successive writings, proof that the right road to the solution of the great questions of classification had not yet been found. We have, therefore, two new and almost simultaneous phylogenetic classifications, by two of the most eminent living authorities, both predicated in part upon the insufficiencies of Wachsmuth & Springer's. system, and each believed by its author to be a new and correct reading of the race history of the crinoids. From such sources, and following such a preface, we should not unnaturally expect a brilliant illumination of the road, in search of which their predecessors have floundered in darkness. But to our dismay we find that instead of celebrating a conclusive settlement of these questions, we are only invited to witness fresh controversy. For these new chroniclers do not read their history alike, and their two classifications are about as diametrically and fundamentally opposite as anything could be."

Uintacrinus presents a striking resemblance to the living crinoid Actinometra in the eccentric position of its mouth, the central position of the anus, the absence of any calcified ambulacral skeleton on disk, arms and pinnules, the structure and distribution of the disk ambulacra, the form and proportions of brachials, and distribution of syzygies, the variable size of the anal tube, and the instability of the base.

The systematic position of Uintacrinus will be a matter of controversy for a long time to come. As yet hardly any two authorities agree in placing it in the same position.

Wherever it may belong, and whatever its line of descent, there is no doubt that Uintacrinus is both a protean and convergent form more remarkable than any we have hitherto encountered among the crinoids. Along with great variability in the base and interbrachial regions, it combines :

The interbrachial system and fixed pinnules of the Camerata ;

The pliant test of the Flexibilia;

The large visceral cavity of both of these;

The exoclyclic disk and open ambulacara, and the arms, pinnules, and syzygies of Actinometra ;

The free floating character of the Comatulæ ;

The dicyclic base of the Dicyclica;

The monocyclic base of the Monocyclica.

A noteworthy feature that should receive special mention in connection with this monograph is the distribution of study material, illustrating the points and structures discussed, to some of the principal museums. It is a feature that could well be imitated by other workers in paleontology. In this way the principal type specimens have been deposited in the Museum of Comparative Zoölogy. A large slab has been placed in the National Museum at Washington; it contains specimens exhibiting most of the characters discussed. A fine series of specimens have also been sent to the British Museum, and to the Royal Museum of Natural History at Berlin, where they will be accessible to European students.

2. As stated by Dr. Clarke, in his prefatory note to the Oriskany Fauna of Becraft Mountain, the original purpose of his work was solely to depict the character and composition of the Oriskany fauna of Becraft Mountain, which of itself displays many features of interest. In its progress, however, various questions have arisen which concern the intrinsic value of the fauna and its importance in correlation. Yet without an understanding of the fauna itself it would be impracticable to discuss the latter problems, and for this reason the title of the paper is restricted to the principal argument of the work, to which the discussions of a somewhat broader scope are corollaries.

A fauna which finds its highest development at Becraft Mountain, near Hudson, in Columbia county, N. Y., links together in the character of its species, the calcareous shales and limestones of the Lower Helderberg and the normal Oriskany sandstone.

The interesting bearings of this assemblage of species, its new forms and new associations and its real importance in the correlation of the Lower Devonian are sufficient reason for presenting its characteristics in detail.

A brief account of the stratigraphy of the mountain is given, and also the general New York section as recently revised. Accompanying these is a small geological sketch-map of the Becraft Mountain syncline.

The greater portion of the memoir is devoted to the description of species, which are finely illustrated by nine plates of figures. A table of the vertical range of species occurring in the region is given.

With our present knowledge there are thus 113 recognizable, distinct specific forms in the fauna of the Oriskany at Becraft Mountain, and of these 94 are identifiable with species already known or are clearly new forms peculiar to the fauna. Of the 94, 25 preceded the introduction of the Oriskany sedimentation, having been first described from the fauna of the Helderbergian. In the arenaceous beds of the Oriskany 23 occur; 10 range upward into the faunas of the Upper Helderberg (Ulsterian), but a part of these are restricted to the sandy, lower beds of this formation (Schoharie grit), and others have been noted only in the chert beds of Ontario, Canada, where the intermixture of Oriskany and Onondaga species is well marked and has been recorded by Schuchert. The fauna contains 35 species which so far as known are peculiar to it. On farther analysis of the table, it is evident in some cases that species which range down and upward are restricted to particular groups. Thus the alien trilobites are from the Helderbergian; the gasteropods are exclusively Oriskany; while the alien lamellibranchs are mostly Helderbergian. But the leading factor of the fauna, the brachiopod, has its derivation as freely from below as in the Oriskany invasion.

The faunal values of the different species are then summed up. Concerning the nature of the Oriskany fauna of New York, the author says:

The fauna of the calcareous Oriskany is in no sense a mixed assemblage, or an intermingling of faunas of adjacent provinces. The sequence of life has continued without interruption from the Helderbergian (Kingston beds) into the sediments of the Oriskany and Onondaga limestone.

It is extremely probable that important variations from the fauna of the Catskill shaly (New Scotland) limestone had already made their appearance in the Becraft limestone, and that we first become acquainted with some of these in the study of the calcareous Oriskany. No proof therefore could be adduced more emphatically confirmatory of the intimate faunal relations of the Helderbergian with the Oriskany fauna and its successors than the facts brought forward in this paper.

The fauna discussed is that of the calcareous facies of the Oriskany formation. The sedimentary deposits of this and the neighboring sections were essentially limestones notwithstanding the silicious content, whether diffused through the mass or segregated as cherty secondary product. In the earlier presentation of this fauna it was regarded as of lower Oriskany horizon on account of the presence of many Helderbergian species, but we believe it will be more correctly construed as the representative of the proper and normal Oriskany fauna, the true fauna of this time-unit inclosed in the sediments of its proper habitat.

A chapter is devoted to discussing the Devonic age of the Helderbergian fauna and the base of the Devonic system in New York.