189 2.] Geology and Paleontology. :}3l 



points of identity with Eocene deposits elsewhere are mentioned. 

 Two groups of strata are recognized, one marine (Tejoo group), the 

 other brackish (Puget group). 



region were accumulated and the interesting buna and flora that they 

 afford are fully discussed in the linal division of the essay. The -.'enoral 

 relations of the fauna and flora of the Eocene of the interior to that of 

 other regions is pointed out, though no attempt is made at a detailed 

 correlation of its various members. The Laramie problem, although 



is here referred to, and the facts are given which are said to show- 

 that the Laramie is in part Loccne. The eontlict between the evidence 

 afforded by animals and plants is stated with the consequent hindrance 

 to satisfactory correlation. 



Dr. Clark incidentally to the subject gives a historical discussion of 

 the Laramie formation which he finally excludes from the Eocene 

 series. This discussion is of much interest as showing the growth of 

 opinion based on accumulating evidence. He might have been a 

 little more explicit in his reference to the first determination of the 

 Cretaceous age of the Laramie formation. He says, (p. 114), "Prof. E. 

 D. Cope (Amer. Philos. Soc. Trans, xiv, 186-9, pp. 1-252) raises a 



doubt concerning the Tertiary age of the entire lignitic series by 



Leidy from the 'Great Lignitic' 

 of Nebraska as perhaps of Cretaceous age, and Hadrosaurus t occiden- 

 tal's Leidy from the 'Cretaceous beds of Nebraska.' " etc. There was 

 however more than the " raising of a doubt " expressed in the memoir 

 by Cope thus quoted. He says, p. 98; " I instituted an examina- 

 tion of the forms brought by Dr. Hayden from this locality [Nebraska] 

 and first of that most characteristic animal the Ischyrotherium of 

 Leidy. This, as has appeared on the preceding pages I believe to be 

 a reptile allied to Plesiosaurus, a conclusion which at once ettabHAtA 

 Mesozoic age of the bed. It coincides with the presence of Hadrosaurus 

 in indicating Cretaceous or upper Jurassic age." 



We observe with surprise that Dr. Clark does not include the 

 Plistocene in the Cenozoic series. We suppose he would relegate this 

 age to a distinct realm, the so-called Quaternary. But the propriety 

 of such a classification has, in our opinion yet to be shown. 



Dr. Clark remarks (p. 16) ; "the term Eocene which is retained as 

 equivalent to Lower Tertiary, may or may not coincide with the 

 division so " We would suggest 



then why adopt the term Eocene at all? One is led to suppose from 



