546 



SCIENCE. 



[Vol. IX., No. 226 



quence of their oldest fossiliferous rocks still re- 

 mains to be determined." The reason of this 

 uncertainty is not far to seek : it lies in the ex- 

 ceedingly complex arrangement of these rocks 

 along the Atlantic seaboard of the United States, 

 where till lately they had alone been studied. 

 Now, however, this reproach is beginning to be 

 taken away from us, and one of the most valuable 

 contributions to the solution of the problem is 

 given by Mr. Walcott in the paper before us. 



In the introduction the stratigraphical relations 

 of the Cambrian rocks in Vermont, New York, 

 various parts of Canada, Nevada, Utah, and Ari- 

 zona, are described and illustrated with sections, 

 and this part of the work is of peculiar interest. 

 The great development of these rocks in the west, 

 and their almost undisturbed position, render 

 them of the utmost importance in deciphering the 

 early histoi-y of the continent. Especially is this 

 true of the region of the great Colorado Canon in 

 Arizona, where is found an immense thickness of 

 unaltered strata which Mr. Walcott considers to 

 be of pre-Cambrian age. The elucidation of its 

 fossils will be awaited with great interest by all 

 biologists as tending to bridge over the great gap 

 between the archean and paleozoic eras. 



Mr. Walcott's studies lead him to the same results 

 reached by the English geologists ; namely, the 

 division of the early paleozoic series (omitting the 

 supposed pre-Cambrian) into three systems, — the 

 Cambrian, Ordovician (lower Silm-ian), and Si- 

 lurian (upper Silurian). On this head Mr. Etheridge 

 remarks, " The recognition of a tripartite group- 

 ing of the faunas and strata between the base of 

 the old red sandstone and the Harlech series can- 

 not be disputed : each is characteristic and pos- 

 sesses a broadly marked aspect or facies." In the 

 Cambrian system Mr. Walcott recognizes three 

 series, — a lower, middle, and vipper, — which cor- 

 respond respectively to the St. John's group, the 

 lower and upper Potsdam of Sir William Logan. 

 The lower Cambrian fauna is not known to occur 

 west " of a line passing north-east through east- 

 ern Massachusetts, New Brunswick and Newfound- 

 land ; "' being kept out of the internal basin, Mr. 

 Walcott believes, by a barrier extending from Lake 

 Superior south to Texas, and west to Arizona. 

 The middle Cambrian fauna would seem to be pe- 

 culiar to America, not being represented in Wales, 

 Scandinavia, or Bohemia : its nearest representa- 

 tive in Europe is on the island of Sardinia. If 

 these results are confirmed, a great advance will 

 be gained. 



Most of the paper is taken up with a systematic 



Second contribution to the studies of the Cambrian 

 faunas of North America. (U.S. geol. surv., touU. No. 30.) 

 Washington, Government. 8°. 



account of the middle Cambrian fauna of North 

 America, by far the most complete yet given. 

 Forty-two genera (three of them new) and ninety- 

 six species, of which sixteen are new, are fully 

 described and figured. Especially interesting are 

 the curious archeocyathoid sponges, which have 

 so many features recalling certain paleozoic corals, 

 the remarkable primitive pteropods, Hyolithesand 

 its allies, the oldest known cystidean, and the 

 great series of trilobites (fifteen genera). Mr, 

 Walcott has accomplished much with fragmentary 

 material, but the morphological results of the 

 study of these early faunas are not very promis- 

 ing. 



A gratifying aspect of this paper is its substan- 

 tial confirmation of Emmons's work on the Ta- 

 conic system, — a work which must ever excite 

 admiration when its difiiculties are considered. 

 " Dr. Emmons deserves great credit for the work 

 that he did. Struggling under adverse circum- 

 stances, at a time when there was almost nothing 

 known of the pre-Potsdam strata of North Amer- 

 ica, and when geologic methods were yet in their 

 beginnings, he accomplished a work in one of the 

 most complicated regions of American geology, 

 the central idea of which ... we now know to 

 be correct." 



It should be remembered that in this paper ]\Tr. 

 Walcott has given a study, and not a complete 

 and final expression of his views. Only a begin- 

 ning has been made in a great undertaking, but 

 it would be difficult to exaggerate the value of 

 the work already done, which now offers a series 

 of well-defined questions for solution, instead of 

 the chaos which reigned but a few years ago. 



Trichinae have been discovered in a human 

 body which was being prepared for anatomical 

 demonstration at the University of Camerino. The 

 man had lived for many years in a neighboring 

 commune, and died without the presence of the 

 trichinae being suspected. Peculiar interest at- 

 taches to the case for the reason that it is said to 

 be the first case of trichinosis ever observed in 

 Italy. 



— Professor Poncet of Lyons recently had un- 

 der his care a man whose tibia had been broken 

 and had failed to unite. Between the ends of the 

 broken bone he attached the half of the first joint 

 of a great toe, taken from a limb which had just 

 been amputated. The piece thus attached formed 

 adhesions, at one end fibrous and at the other 

 bony. Whether the bone thus strengthened was 

 of use, the report does not state. 



