available data, and has made the type of Uintacrinus the subject of a a special morphological study. In this treatment the previous work is briefly referred to; but some of it receives criticism that it does not appear to deserve, particularly since the foundation of most of the adverse comments lies not in any material error in the work referred to, but in what is manifestly a clear misinterpretation or hasty perusal of that work. It is to certain of these points in the structure of the form that attention is directed in the present note. In making the correction, however, it is not with the idea of reflecting on Mr. Bather's paper as a whole, for it is one of the most excellent contributions to echinoderm morphology that has yet appeared. The original figures in question from Bulletin 97 of the U. S. Geological Survey are herewith reproduced (Plate XV) in order to make more intelligible the exact points under consideration.

In the memoir mentioned considerable space is occupied in criticising a recent account of the species; but most, if not all of the objections urged against Doctor Clark's work, are certainly more imaginary than real. Professor Clark's figures come in for special condemnation as violating the fundamental law of the alternation of the pinnules. As a matter of fact his plate which is reproduced in the Proceedings as Plate LVI, to point out the alleged errors, not only shows that the accompanying statements are not true, but that in all three figures there is strict alternation of the pinnules in every case.

The general law in the pinnulation of the genus Mr. Bather states as follows: IIBr, none, IIBr, outer, IIBr, none, IIBr, inner, IIBr, outer, IIBr, none, IIBr, inner, IIBr, outer, IIBr, none. Two of his ten specimens differed from this general rule: one showing IIBr, inner, IIBr, none, IIBr, outer, IIBr, inner; and the other IIBr, none, IIBr, outer, IIB, inner, II Br, none, IIBr, outer. He makes out the formula for the Clark figure la to be IIBr, outer, IIBr, none, IIBr, outer. The real formula for this is IIBr, outer, IIBr, inner, IIBr, outer, IIBr, inner, IIBr, outer. This appears clearly indicated in the figure, and Mr. Bather's statements that IIBr, has no pinnule is certainly a typographical error, for it cannot be that he mistook the rough, broken and highly raised edge of the brachial row of plates, with its deep shadow, for a suture line connecting with the first inside pinnule. The figure is of a somewhat crushed and distorted specimen, and the perspective is, perhaps, not as good as it might be. Whether or not it is the same as that figured by Meek (Bather's figure 2) is not known; but if the two are the same, the difference in the sketches are not very great nor radical, and certainly not as contradictory as Mr. Bather would have

available data, and has made the type of Uintac a special morphological study. In this treatm briefly referred to; but some of it receives appear to deserve, particularly since the adverse comments lies not in any mate to, but in what is manifestly a clear of that work. It is to certain of form that attention is directed correction, however, it is not paper as a whole, for it is echinoderm morphology' question from Bulletir reproduced (Plate points under cons*

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only real difference is that in Meek's figure there is innulated brachial separating two pinnule bearing extra plate is shown in figure 1c. The intercala'plate of this kind is of common occurrence uld not excite any wonderment, let alone adJintacrinus this is of frequent occurrence, not only mens but also in the different arms of the same indiBather himself shows that two out of the ten examples examined do not agree with his general formula. If his vations could have been extended it might have been found that e in three is just about the proportion of the individuals that do not agree in this respect. It might be added parenthetically that of 200 specimens of Uintacrinus that have been personally examined, fully one-half of them appear to vary in a similar way in the mode of pinuulation.

Granting then that Meek's original figure is correct in every detail and that figure la of Professor Clark's plate represents the same specimen, the differences are practically immaterial. Professor Clark's work not only does not violate the fundamental law of pinnulation but is essentially correct so far as typifying the species. The very object of adding an enlarged view of another specimen (figure 1c) was to make more clear the arrangement of the pinnules, since the convexity of the principal specimen and its distortion somewhat misrepresented these points. The same may be said of IIBr, in figure 1c. Usually from IIBr, on, the pinnules are turned in or are covered by the matrix if the specimen is not carefully cleaned, and consequently do not show from above. That IIBr, should be visible on one arm and not on another is not strange, and not necessarily incorrect.

Regarding Mr. B. H. Hill's diagram the formula given by Mr. Bather is probably correct for the figure; but, as he has stated, it is diffi cult to decide the question owing to the " rather peculiar mode of representation." It seems hardly possible that this diagram correctly represents the pinnulation of the specimen from which it was taken, and the entire disagreement of the corresponding plate faces when separated would further indicate that the figure is, as stated by Mr. Bather, "hopelessly incorrect," or illustrates a new species.-C. R. KEYES.

Geological News.-PALEOZOIC.-From data recently compiled, Prof. C. R. Keyes estimates the total maximum thickness of the Paleozoic rocks in the middle part of the central Mississippi basin, that is, in the neighborhood of the Missouri River, between Kansas City and the Iowa