470 Scientific Intelligence. 



stones, with a heavy trap overflow, attain a thickness of about 

 2800 feet. "This great thickness is not found on the west side 

 of the bay." In the Sutton Mills Lakes region, 90 feet of sand- 

 stones and slates are shown " capped by an extrusive trap show- 

 ing a thickness of 150 feet." These rocks " present many features 

 in common with those from the Animikie of Thunder Bay." No 

 fossils are mentioned. 



Overlying the Cambrian is " a flat-lying limestone, which forms 

 a wide belt around the west shore of James Bay and along the 

 southern shore of Hudson Bay. On the Albany River the upper 

 part of the series is proved to be of Devonian age, and beneath, 

 at a greater distance from the sea, Silurian limestones are exposed. 

 These beds probably overlap any older ones that may be beneath, 

 and rest directly on the Archaean." The Silurian dolomitic lime- 

 stone " does not appear to be of any great amount, probably not 

 over 20 feet." The geologic series is terminated by Post-Ter- 

 tiary clays containing Saxicava rugosa, My a truncata, Macoma 

 calcarea, and Cardium ciliatum. 



According to Whiteaves, the Silurian fauna consists of 55 

 species, of which 39 are specifically named, 26 being restricted to 

 the James Bay region. The percentage of new species is there- 

 fore rather high, but not greater than one would expect from a 

 region so widely separated from other known Silurian areas. The 

 assemblage both of species and faunal facies is not that of the 

 Rochester or lower Lockport. as none of the characteristic forms 

 of these well-known faunas are present. 



On the other hand, it is directly comparable with the Guelph 

 of Ontario and the higher Niagaran dolomites of Illinois and 

 Wisconsin. This is seen in Pycnostylus guelphensis, P. elegans, 

 an almost total absence of the lower Niagaran corals, cystids, 

 crinoids, and brachiopods, and in the prescence of 2 species of 

 Trimerella, 1 Salpingo stoma, 3 Gyronema, and 3 Bronteus. c. s. 



3. Zinc and Lead Deposits of Northern Arkansas, etc. With 

 a Section on the Determination and Correlation of Formations ; 

 by E. O. Ulrich. Prof. Paper, No. 24, U. S. Geol. Survey, 

 1904, pp. 90-113.* — Ulrich's contribution is important because it 

 attempts to correlate the Paleozoic formations of northern 

 Arkansas and southern Missouri with " a standard time scale of 

 the Ohioan Province." By "Ohioan Province" the author means 

 the eastern half of the Mississippian sea, and also objects to using 

 the latter term for this province because the name Mississippian 

 "has a fixed application to the Lower Carboniferous rocks of 

 America." In northern Arkansas, the Paleozoic section consists 

 of the equivalents in the Ordovician of the Oneonta, Shakopee, 

 St. Peter, Lorraine, and Richmond ; in the Silurian of the Clin- 

 ton ; in the Devonian of the Chemung, and in the Carboniferous 

 of a complete sequence from the Kinderhook into the Pottsville, 

 except that the Warsaw and Spergen Hill are absent. From this 

 it is seen that great breaks in deposition occur in the Ordovician, 

 and from the basal Silurian through to the Upper Devonian. 



* See also p. 394 of the November number. 



