WAR1..J HISTORICAL REVIEW OF OPINION'. 425 



and eiuliug it above with those strata in which the brackish- water forms 

 flnallj' cease. Thus defined, tlie whole series seems to form one natnnil 

 paleontological group, as well as to be a sufficiently distinct strati- 

 graphical one, for which I have adopted the name of Laramie group of 

 King." 



In giving his reasons for adhering to the name Post-Cretaceous, Dr. 

 "White further says: "The flora of this group is understood to be wlioJly 

 of Tertiary types, according to Professor Lesquereux. None of its in- 

 vertebrate fossils are of distinctive Cretaceous types, although fossils 

 of simihir types are known to occur in Cretaceous as well as Tertiary 

 strata. So far, then, as the flora and invertebrate fauna are concerned, 

 there is nothing to indicate the Cretaceous age of the group. In fact, 

 invertebrate paleontology is utterly silent upon the subject. On the 

 contrary. Professor Cope finds reptilian remains, even in the uppermost 

 strata of the group, that he regards as of Cretaceous type. I believe 

 that, upon the evidence of invertebrate paleontology, the Fox Hills 

 group is later than the latest Cretaceous strata of Euroi)e; and I there- 

 fore regard the Laramie group as occupying transitioHal ground be- 

 tween the well marked Cretaceous and Tertiary groups, but this opinion 

 is only tentatively held until further facts are obtained." 



The term Post- Cretaceous is employed by both Endlich and Peale in 

 their reports in this volume (pp. 77, 109, 181). 



In his seventh Paleontological Paper (Bulletin U. S. Geological Sur- 

 vey of the Territories, Vol. IV, No. 3), distributed in 1878, Dr. White 

 greatly extends the boundaries of the Laramie group, making it em- 

 brace "both the Judith Eiver and Fort Union series of the Upper Mis- 

 souri Kiver ; the Lignitic series east of the Kocky Mountains in Colorado; 

 the Bitter Creek series of Southern Wyoming and the adjacent parts 

 of Colorado; and also the 'Bear River estuary beds,' together with the 

 Evanston coal series of the valley of Bear River and adjacent parts 

 of Utah," as well as strata known to exist in other large and widely 

 separated districts of the western portion of the National domain, and 

 he gives a list of species characteristic of the group, showing their dis- 

 tribution throughout these several districts. 



Mr. Leo Lesquereux's so-called " Tertiary Flora" constitutes the 

 seventh volume of the final reports of the Geological Survey of the Ter- 

 ritories under Dr. F. V. Hayden, which, of course, embraces the plants 

 of the Laramie group. In it Mr. Lesquereux has given full scope to the 

 expression of his views upon the age of this group, and it is naturally 

 here that we must look for the most able and exhaustive treatment of the 

 subject thus far presented by this author. In the letter of Dr. Hayden 

 to the Secretary of the Interior transmitting this report, and which bears 

 date January 1, 1878, he again reviews this subject and remarks: "The 

 author states that his final conclusions do not ditt'er materially from 

 those already advanced by myself, and he regards the evidence as con- 

 clusive that the Lignitic group is of Tertiary age. This result is grati- 



