^,v>* 



rv 



4'^4 I'LORA OF THK LAKAMIK GROT'P. 



than the Eoceae epoch, that 1 Lave decided to designate those strata 

 as I'ost-Cretaceous, at least provisionally." 



By a remarkable coincidence this term Post- Cretaceous was applied 

 to the lignitic beds of the Trinidad district, New Mexico, by Dr. F. M. 

 Endlicli, in the Annual Eeport of the Geologi(!al Survey of the Territo- 

 ries for 1875 (p. 206), published in 1877; but it is impossible to say 

 which of these reports should have priority, and as the term has now 

 been generally abandoned this is quite unimportant. 



In the death of Mr. F. B. Meek the science of invertebrate paleon- 

 tology lost one of its ablest votaries, and but for the fact that Dr. C. A. 

 White had already entered the field iu this role as well as in that of 

 stratigraphical geologist, this department of research in our western 

 n \ formations might have been sadly neglected. But the now rapidly in- 



\^f\ /I ( }y* creasing writings of the latter author fully supplied the place of the 



'ii i . ■ /^ ' former, and the contest went on. In the Annual Eeport of Dr. Haj^- 



den's Survey for 1S7C, published in 1878, Dr. White reports his opera- 

 ^ tious during the years 1876 and 1877 in Colorado, in which paper he 



takes occasion to draw up a section of the rocks and to prepare a table 

 of correlated general sections which are highly instructive. Continiug 

 ourselves to the Laramie group, we see that he adopts that term and 

 makes it commensurate with his Post-Cretaceous, to which he still ad- 

 heres, and also with tiie Laramie of King and the Lignitic of Meek and 

 J Hayden. The Point of Rocks group of Powell begins with the Laramie, 



but stops at a lower horizon, his Bitter Creek group occujjying the re- 

 mainder, and the whole of the Wasatch (the Vermilion Creek group 

 of King). In defense of his course in receding from his former posi- 

 tion, in which his views agreed with those of Powell, he says: "After 

 a careful examination of the extensive exposures of this series of strata, 

 as well as those of the Wasatch group above it in this district, I have 

 failed to discover any unconformity such as exists iu the valley of Bit- 

 ter Creek. Therefore, the greatest unconformity that is now known to 

 exist among any of the strata from the base of the Cretaceous to the 

 top of what 1 here designate as the Post-Cretaceous, is found among 

 the strata of the latter group, and not at its top. In this district and 

 the region immediately adjoining it, whatever catastrophal or secular 

 changes may have meanwhile taken pLace elsewhere, or even extending 

 within its limits, sedimentation was evidently continuous and unbroken, 

 not only through this series itself, but also into and through the whole 

 Wasatch group. 



" The fact that this series passes insensibly into the Fox Ilills group 

 below, and into the Wasatch groni> above, renders it difficult to fix 

 upon a stratigraphical plane of demnrkation, either for its base or sum- 

 mit. 1 have, therefore, decided to regard this group as essentially a 

 brackish-water one, referring all strata below that contain any marine 

 Cretaceous invertebrate forms to the Fox Hills group, beginning this 

 series with those strata that contain brackish- and fresh-water forms, 



