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A REVIEW OF THE FOSSIL FLORA OK NORTH AMERICA.* 



BY LEO LESQUEP.EUX. 



For years, the explorations of Dr. F. Y. Haydeu in the Rocky Monnt- 

 ain regions, pnrsued under the direction of the Department of the 

 Interior, have awakened a deep and general interest by the remarkable 

 natural phenomena which they have brought to light. Not only have 

 these explorations penetrated into unknown regions, tracing out broad 

 areas, the existence of which was not fully realized, and the discovery 

 of which has been recorded as of as great moment as any of those 

 made at our time : not only have they reported great valleys in the 

 midde of the mountains 5 parks prepared by their fertility for a future 

 population ; rich mining-districts abounding in precious minerals ; won- 

 ders of nature also, like the Geysers of the Yellowstone, rivaling in 

 splendor the greatest marvels of the world : but they have opened to 

 science new fields of researches, where American naturalists have found 

 treasures of fossil remains, a world of unknown species of animals and 

 plants, which enrich beyond expectation the annals of science of this 

 country. The discoveries of remains of huge saurians and of mam- 

 mifers, of deposits of rocks composed of shells of remarkable kinds,, 

 have been already recorded at different times, and even telegraphed 

 through the country on account of their importance. 



The great Lignitic coal-fields also, extending along the base of the 

 Eocky Mountains in the whole width of the United States Territories, 

 from New Mexico to Oregon, were scarcely known before the explora- 

 tions of Dr. Hayden, who defined their outlines and areas, and recorded 

 the multiplicity and richness of their deposits of coal. The Lignitic is 

 for the West what the great Apijalachian coal-region is for the Bast, but 

 more valuable still, perhaps, for the commonwealth, as without these 

 deposits of combustible mineral the Rocky Mountain regions, and the 

 great western plains at their base, would be uninhabitable. 



A special branch of the researches pursued by Dr. Hayden's explo- 

 rations relates to vegetable paleontology. Collections of fossil iilants 

 have been extensively made under his direction, especially with refer- 

 ence to the determination of the geological age of the Lignitic formations 

 and of the Cretaceous Dakota group of Kansas. It is on this subject of 

 vegetable paleontology that this article is written. I do not propose, 

 however, to give herewith a description, nor even an enumeration, of 

 the species of fossil plants which were discovered by Dr. Hayden ; but 

 to go through an abridged review of what is known as yet of the North 

 American fossil flora, marking some of its essential characters at differ- 

 ent periods, pointing out some of the results that have been already 

 obtained by the application of vegetable paleontology to physical and 

 geological science, and what we may expect from it when the field, 

 scarcely opened, is explored with more interest and more exhaustive 

 researches. 



A brief history of our North American flora, in regard to the origin 



* This article was originally prepared, at my request, for the Penn Monthly, at Phila- 

 delphia. So much value has been attached to the essay that it seemed to me desirable 

 that it should hav^e a wider circulation among scientific men. I therefore requested the 

 author to revise it for the Bulletin, and it is here rej)rinted with many important 

 additions. F. Y. H. 



No. C 1 



