Geology. 151 



cially interesting are the outline sketches of the associated ani- 

 mals of the various faunas. 



In the introduction Osborn discusses the North Polar theory 

 of the origin of land mammals near the North Pole, whence they 

 spread southward, ascribing the idea to Haacke in 1886. It is 

 but just to state that an earlier writer, G. H. Scribner, advanced 

 a similar thesis as to the origin of the flora and fauna of the 

 earth in his little monograph entitled " Where did Life Begin ?" 

 and published in 1883. Except for this the bibliography is 

 apparently very complete and the appendix also contains a new 

 and copious classification of the mammalian genera, living and 

 extinct. 



The volume is an excellent example of bookmaking and the 

 type clear and legible, the principal room for criticism being the 

 half-tones, many of which, notably those of Knight's drawings, 

 do not do justice to the originals. R. s. l. 



3. Tertiary Fauna! Horizons in the Wind River Basin, 

 Wyoming, with Descriptions of New Eocene Mammals; by 

 Walter Granger. Bull. Amer. Mus. Nat. Hist., Vol. xxviii, 

 Art. xxi, 1910, pp. 235-251, with 6 text figs, and 3 pis. — This 

 excellent little bulletin by Mr. Granger summarizes his work of 

 exploration in the Wind River Basin as follows : — 



" 1. The Wind River Basin is covered throughout the greater 

 part of its area with beds of the Wind River group, pertaining 

 to the Lambdotherium Zone. 



" 2. Mammalian remains are extremely rare or absent from 

 these beds except in two localities in the northern and north- 

 eastern part of the basin, viz., along Alkali Greek and between 

 Muddy Creek and the Owl Creek Mountains. 



"3. Lying along the northern border of the Tertiary deposits 

 in the northeastern corner of the basin, between the foothills and 

 the Lambdotherium beds, apparently older than the latter and 

 with the best exposures along Cottonwood Creek, is a series of 

 350 feet or more, containing a fauna intermediate between the 

 Lambdotherium Zone and the Coryphodon Zone of the Big Horn 

 Wasatch, the genera being all common to both zones. 



" 4. Along the southern border of the basin, on the divide 

 between Sweetwater River and Beaver Creek, there is exposed a 

 thickness of 1,100 feet of Tertiary, a remnant of deposits which 

 undoubtedly extended over a large part of the basin at one time. 

 Three distinct faunal levels, as indicated by mammalian fossils, 

 are exhibited, Lower Eocene, Upper Eocene, and Lower Oligo- 

 cene, the levels being correlated with (1) the ? Coryphodon Zone 

 of the Wasatch, (2) the ? Diplacodon Zone of the Uinta, and (3) 

 the Titanotherium Zone of the White River. An unconformity 

 exists between the Eocene and Oligocene, but no break in sedi- 

 mentation was detected in the Eocene series. 



" 5. Between the Coryphodon and Diplacodon levels are sev- 

 eral hundred feet of unfossiliferous beds, the lower part of 

 which pertain probably to the Lambdotherium Zone of the White 



