Columbus, Ohio, February 12, 1874. 

 Dear Sir : I send you herewith my report on the fossil flora of the Cre- 

 taceous Dakota group. 



Allow me to gratefully acknowledge the assistance received from you in 

 the preparation of this memoir. The opportunity offered to me of exploring 

 the more interesting localities where the materials for this work have been 

 obtained was especially of great advantage. It enabled me to become ac- 

 quainted with the geological distribution of the formation; to study the vege- 

 table remains, and to compare their various forms in places where they were 

 more abundant ; to recognize their local disposition, and thus to solve many 

 questions which, without this advantage, would have been left indefinite. 

 Very respectfully, yours, 



L. LESQUEREUX. 

 Prof. F. V. Hayden, 



United States Geologist, Washington, D. C. 



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