AGE OF THE LIGNITIC DETEEMINED BY ITS FLORxX. 311 



my visit, he enleied at once with the greatest zeal into the work of explora- 

 tions, and presented to the Survey all the materials of value discovered 

 by our common researches in the country around Golden. It will be seen in 

 the descriptions that he sent later, from Point of Rocks and from Alkali 

 Station in Wyoming, a large lot of specimens, some of them representing 

 new species of leaves in very good preservation. Other communications from 

 the Lower Lignitic are due to Prof F. B. Meek, and to Mr. Geo. Hadden, of 

 Coal Creek, Colorado. From Fort Fetterman, Lieut. A. W. Vogdes sent two 

 lots of fossil plants, mostlj' fragments of Taxodium, referable to the Laramie 

 or third group. The specimens of Prof E. D. Cope from the Upper Green 

 River group, Castello's Ranch, Florissant, and Elko Station, represent, with 

 those of Prof Wm. Denton and Dr. F. V. Hayden himself, the largest part 

 of the species described from this formation. A few specimens were 

 also sent by Profs. J. A. Allen and S. W. Garman, and more recently by 

 Prof A. Brownell. These last were received after the preparation of the 

 plates, and too late to be figured: but the new species which they represent 

 have been described. 



From the Lower Green River group, nearly all we know is derived 

 from the specimens sent by Dr. Hayden, from above the fish-beds of Green 

 River Station. 



The members of the Geological Corps of the United States Survey of 

 the Territories, Dr. A. C. Peale, A. R. Marvine, J. T. Gardner, AV. H. Holmes, 

 and Jos. Savage, have occasionally give their attention to the collection of 

 fossil vegetable remains, and pi'ocured some valuable materials from localities 

 out of the reach of private explorations. They were encouraged to do so by 

 Dr. Hayden, who, in his expedition of 1875, obtained himself, from Point of 

 Rocks and from the Parks, splendid materials, constituting an important 

 contribution to the American Tertiary flora. 



It may be unnecessary to state that the contribution of specimens 

 of fossil plants, too often mere fragments, sent in small lots from separate 

 and distant localities, continued for a series of years, and that the necessity 

 ' of reporting on them for each Annual Report required repeated com- 

 parison and revisions of the first specifications. Therefore, the original 

 determinations of S23ecies estabhshed from insufficient materials have, in 

 some cases, been recognized as incorrect, and the names changed. And 

 also, while the Flora was in course of preparation, I obtained the generous 



