Geology and Mineralogy. 221 



South Africa, although the two widely separated groups are 

 closely related. In South Africa the specializations were clearly 

 toward the Mammalia, while those in this continent tended in the 

 direction of higher Reptilia. c. s. 



3. The Mesozoic and Cenozoic Echinodermata of the United 

 States • by W. B. Clark and M. W. Twitchell. Monograph 54, 

 IT. S. Geol. Surv., 1915, pp. 341, 108 pis.— This valuable and 

 comprehensive monograph brings together all that is known bio- 

 logically and stratigraphically of the Echinodermata of the 

 American Mesozoic and Cenozoic strata. In Part I the senior 

 author describes the Mesozoic forms, of which there are 117 

 (Crinoidea, 6 genera and 14 species ; Stelleroidea, 7 genera and 

 9 species ; Echinoidea, 35 genera and 94 species). The second 

 part, by Clark and Twitchell, treats of 138 Cenozoic forms (Cri- 

 noidea, 1 genus, 1 species ; Stelleroidea, 3 genera and 6 species ; 

 Echinoidea, 43 genera and 131 species). There are no species in 

 common with either Europe or Asia. All of the forms are well 

 illustrated, so that from now on paleontologists will be able to 

 easily determine their fossil echinoids. c. s. 



4. Upper White River District, Yukon; by D. D. Cairnes. 

 Memoir 50, Geol. Surv. Canada, 1915, pp. 191, 17 pis., 2 text figs., 

 3 maps. — The author here describes the various routes of travel 

 into the upper White River district, Yukon, and the topography, 

 geology, and mineral resources of the country. The pre-Cambrian 

 metamorphics are followed by Carboniferous, Mesozoic, and Ceno- 

 zoic formations. Copper and gold are the more promising of the 

 economic products. 



5. The Devonian of southwestern Ontario / by Clinton R. 

 Stattffer. Mem. 34, Geological Survey, Canada, 1915, pp. 341, 

 20 pis., 1 map. — In this stratigraphic report Stauffer describes in 

 great detail the Oriskany and Middle Devonian formations as 

 exposed from place to place in Ontario to the north of Lake Erie 

 and between Michigan and Lake Huron east to Niagara Falls. 

 Everywhere he collected the fossils according to horizons and he 

 now also presents the many local faunal lists. On later pages he 

 gathers all of these together under the caption of " Check list of 

 the Devonian faunas " (228-251). 



The Devonian of Ontario is unconformable with the Silurian. 

 In the east the Oriskany sandstone, with the typical New York 

 fauna, is the basal formation, while elsewhere the base is as a rule 

 some member of the Onondaga. The latter loses more and more 

 of its characters as it passes westward from New York and takes 

 on the aspects of the lower members of the Middle Devonian of 

 Ohio. The Marcellus black shale of New York is, in Ohio, the 

 Delaware limestone, which extends into Ontario. On the other 

 hand, the higher members of the Devonian have faunas that 

 relate them to Michigan. 



At the close of the book the author discusses the troublesome 

 Detroit River series (and faunas) that on the accompanying map 

 is colored as Silurian but which the Survey officially regards as of 

 Devonian age. The fauna is in the main held to be undoubtedly 



