53G FLORA OF THE LARAMIE GROUP. 



wliat other deposits on the earth's surface were being made at the same 

 tiinc with those of the Laramie. But we have seen that this cannot be 

 known for any very widely separated areas. Within the Laramie grouj), 

 however, conclusions of this nature are comparatively reliable, and 

 when more is known of this flora and of the characteristic types of 

 dift'erent horizons within it, and different areas occupied by it, there 

 can be no doubt that its value in the determination of the precise hori- 

 zon of new beds both within and without that group must be very 

 great. The following words of Mr. Meek, after a careful survey of the 

 question from the point of view of the invertebrate paleontologist, are 

 equally true for fossil plants: "But it may be asked," he says, "are we 

 to regard all such fossils as of no use whatever in the determination of 

 the ages of strata! Certainly not, because, even in case future dis- 

 coveries in this country and the Old World should never modify the 

 present conclusions in regard to the geological range of * * * these 

 types * * * so as to enable us to use them with more certainty 

 as a means of drawing parallels on opposite sides of the Atlantic, they 

 will undoubtedly be useful, when viewed in their specilnc relations, for 

 the identification of strata within more limited areas. That is, when all 

 or most of the details of the stratigraphy of the whole Eocky Mountain 

 region and the vertical range of species have become well known, these 

 fossils will pei'haps be found nearly as safe guides in identifying strata 

 at one locality with those of others there, as many other kinds." ^ 



But there is a higher ground on which investigations of this nature 

 may be justified. However negative the results may prove, in seeking 

 to make wide generalizations, either for geology or for biology, every new 

 form discovered widens our knowledge of what has been taking place on 

 the surf\ice of the earth since its crust was formed, and the additional 

 knowledge we thus gain of the history of the globe is worth for its own 

 sake all that its laborious pursuit costs, and this quite aside from the 

 added value it possesses in furnishing an ever widening basis for the 

 true laws of both geologic and biologic development. 



RECENT COLLECTIONS OF FOSSIL PLANTS FROM THE LARAMIE 



GROUP. 



I have now completed the review of the flora of the Laramie group 

 which, as stated at the outset, would constitute the first part of this 

 memoir, and will now present the concluding portion, also outlined at 

 the beginning, which will be of a somewhat personal character, and will 

 consist of an attempt to record so much of the little that I have been 

 able to contribute to the stock of knowledge relative to the Laramie 

 flora as has thus far assumed a sufiflciently definite form. It is, however, 



'Report of the United States Geological Survey of the Territories. F. V. Ha.vtlen, 

 Geologist-in-charge. Vol. IX. A Report on the Invertebrate Cretaceous and Ter- 

 tiary Fossils of the Upper Missouri country. By F. li. Meek, p. Ixi. 



