20 COMPARATIVE ZOOLOGY. [Apr. 



During the past season, under the auspices of the Museum, 

 a critical examination of the stratigraphy of our carboniferous 

 formation was begun, with the view of determining the char- 

 acter of the physical conditions which prevailed during their 

 deposition, and how and to what extent these influences 

 affected the life of the successive epochs. Through the interest 

 of Mr. W. C. Van Home, to whom our best acknowledgments 

 are due for the large understanding and aid which he so gen- 

 erously contributed towards furthering the undertaking, the 

 work was commenced in the St. Louis division of the Lower 

 Carboniferous, embracing a thorough study of the formation in 

 the environs of St. Louis, where it presents its typical devel- 

 opment and where especially favorable facilities are afforded 

 for its investigation. The result of the season's exploration 

 was the acquisition of a valuable collection, presenting almost 

 a complete representation of the life-history of that particular 

 sub-epoch, exhibiting the chronological relations of the fossils 

 and many important facts bearing on their fauiial association. 

 These collections are at present in process of arrangement, — 

 the method adopted intending to show the stratigraphic distri- 

 bution of the species. It may be added, that, a full record 

 of the operations of the survey was made, of which a com- 

 plete copy has been deposited in the library. 



Accessions to the collections, extending back two years, 

 comprise the following : — 



Leo Lesquereux, Jr., a specimen of Conocardium from the Devo- 

 nian, Columbus, Ohio. . 



E. A. Strong, in exchange, miscellaneous fossils from the Upper 

 Helderberg of New York, and a collection from the Lower Carboni- 

 ferous formation of Michigan ; in all, 31 species and 175 specimens. 



Wm. Elder, a slab specimen with crustacean trails, carboniferous 

 of Nova Scotia. 



Capt. A. M. Harrison, U. S. Coast Survey, shells from beach 

 deposits, Florida. 



Prof. N. S. Shaler, miscellaneous fossils, Post-tertiary, Martha's 

 Vineyard. 



Dr. G-. A. Williams, in exchange, a fine collection of carbonifer- 

 ous fossils, comprising about 135 species and 2,500 specimens, from 

 the vicinity of Boonville, Missouri. 



