532 PROCEEDINGS OF NKW YORK MEETING. 



if conclusion it can be called, was thai the whole discussion was a war of words, often 

 unworthy of the talent thai bad been expended upon it. 



Prol r J. J. Stevenson : I should like to say a word or two about the section 



that I>r. Newberry ha- put <>n 1 1 1 < - board. The statement that the Colorado group 

 cannot be differentiated in Colorado is not altogether correct. It is true that in a 

 considerable area beyond the Arkansas range it is a very difficult thing indeed to 

 differentiate the Colorado group ; but along the plain in front of the Rocky Mount- 

 ains in Colorado and New Mexico there is not the slightesl difficulty in recognizing 

 tin' Fort Benton as a mass of Mack shale ; the Niobrara above that, gray to blue lime- 

 stones separated by black shale; then the Fori Pierre, drab to yellow sandy shales, 

 containing nodules of limestone and iron ore, while above that and quite easily Bep- 

 arable from it we tind in northern and central Colorado the Fox Hills group. This 



is the Cretan us along the waters of the South Platte, where the Pox Hills ^roup is 



characterized all the way. from the bottom to the top, by a nodose fucoid, Halym 



- major, which was al one time a very interesting topic of discussion. The Fox 

 Hills group in central Colorado is upwards of one thousand feet thick, consisting 

 mostly of sandstones, some of them calcareous and rich in Fox Hills fossils, with some 

 bed- of coal, which have been opened in the neighborhood of Greeley. At Canon < !ity, 

 ('•dorado, the Fox Hills group is only about 350 feet thick, that being the vertical 

 extent of the Halymenites. In that interval are the important coal beds and numerous 

 sandstones or -bales containing plants which doubtless answer to those of the plant 

 bed which I found on one occasion near Evans, on the South Platte, but which I 

 could never tind again. Further southward, near Trinidad. Colorado, the Fo\ Hills 

 i- only v " feet thick, thai being the vertical range of the Halymenites. In thai field, 

 however, the Pox Hill- has been included in the Laramie; but the Laramie group 

 above the great coal-bearing series is easily separable from this Halymenites sandstone. 

 Southward, in New Mexico, the Halymenites or Fox Hills sand-tone entirely disap- 

 pears. 



The point I wish to make is that the upper Missouri section of the Cretaceous is 

 distinctly recognizable as far south as central Colorado. Beyond that southward 

 the Fox Hills thins out until it disappears in New Mexico, but the other members of 

 the section can be recognized without any difficulty in front of the Rocky Mountains 

 and around their southern end to the Rio Grande. 



Professor E. I> Cope: Ii seems to 1 me more complicated the more we investi- 

 gate, and a greater number of problems arise to be Bolved. What Professor Steven- 

 Bon has ju-t given is established. I can demonstrate from my own observation what 

 Dr. Hay den has Btated— that i.-. the conformity of the four or five gradations with 

 the Laramie above. There seems to be absolutely no disturbai r want of con- 

 formity in the upper Missouri between those three horizons. 1 could gel the Pierre 

 I- in the bottom oi the bluff and Pox Hills in the middle and Laramie at the top. 

 On the question of the Laramie's position in the Cretaceous or Tertiary series the 



vertebrate fossils throw some light. The reptiles and -an rain- are Cretan u<. I have 



discovered in New Mexico the Puerco series jusl above the Laramie, and in thai 1 



have about a hundred -| ies of the mammalia. I have also discovered mammalia 



in the Laramie. Professor Marsh has added some species to those previously known. 

 Tic - are of identical character with the Puerco mammal-, although there i- 



no species Identical with any in the Puerco, where there is not a Bingle Cretace 

 reptile. The mammals of the Laramie are. like the saurians, rather Cretaceous than 

 Tertiary : but the character is nol »o pronounced. 



