41 G KLOUA OF THE LARAMIE GROUP. 



Eocene in his last report is Cretaceous, and that another considerable 

 portion [that of the Upper Missouri] is of Miocene age, and he denies 

 that the tiora of any part of the American coal series possesses an Eo- 

 cene fades. Mr. Lesqucreux's reply is of course a defense of his former 

 position and is sui)i)orted by a vast array of facts. 



In the first bulletin of the Geological Survey of the Territories, pub- 

 lished in 1874, Professor Cope, from evidence supplied by vertebrate 

 remains, refers the Great Lignitic of the Upper Jlissouri to the same 

 section of geologic time as the Bitter Creek coal series, now settled in 

 his mind as Cretaceous, and in Bulletin No. 2 (pp. 5-19) api)eared an 

 elaborate report by the same author (reproduced, apparently without 

 change, iu the Annual Report for 1873, also published in 1874 and 

 later than the Bulletins, pp. 431-440), in which he sums up the evidence 

 from the side of vertebrate paleontology. In this report Professor Cope 

 gives Mr. Lesquereux full credit for accurately co-ordinating the data 

 furnished by the vegetable remains, and concludes " that a Tertiary 

 flora iras contemporaneous with a Cretaceous fauna, estahlisliing an unin- 

 terrupted succession of life across what is generally regarded as one of 

 the greatest breaks in geologic tiuie." His further remark that "the 

 appearance of mammalia and sudden disappearance of the large Meso- 

 zoic types of reptiles may be regarded as evidence of migration and not 

 of creation,''^ embodies a thought that has been since revived and ex- 

 tended. 



To this report of Professor Cope, as published in the Annual Eepoit 

 for 1873, he appends a short discussion, not contained in the Bulletin, 

 in the nature of a reply to the article of Dr. Newberry above referred 

 to. In the course of this discussion the following remarks occur: " If 

 a tiora below the Cretaceous of New Mexico resembles a Tertiary one, 

 how much more probable is it that the floras of the Lignites of Colorado 

 and Wyoming are such, as they are known to be of later age than those 

 of New Mexico, and to be at the summit of the Cretaceous series, as indi- 

 cated by aTiimal remains; and if the flora of the Fort Union beds be 

 Miocene, that of the identical horizon iu Colorado must be Miocene 

 also ; and if the vegetation below this flora be so distinct from it, what 

 is more probable, according to the evidence adduced by Dr. Newberry, 

 than that they are Eocene, as maintained by Mr. Lesquereux? That 

 such should be the case is iu harmony rather than iu conflict with the 

 facts presented by the existing life of the earth, where we have the 

 modern fauua of the northern hemis])here contemporary with a partly 

 Eocene and partly Mesozoic fauna in the southern." 



The same volume contains a report by Mr. Archibald Marvine of his 

 operations during the season of 1873 in the park districts of Colorado. 

 In treating the " Lignitic formation," as observed by him, he reviews 

 the evidence from the plant remains, as interpreted by Lesquereux, as 

 well as that furnished by vertebrate life, and says : " It must be sup- 

 posed, then, that either a Cretaceous fauna extended forward into the 



