HISTORICAL SKETCH OF DEEP-SEA WORK. 49 



successors, Professor Benjamin Peirce, Carlile P. Patterson, and 

 Julius E. Hilgard, into the most important hydrographic coast 

 exploration yet undertaken by any government. With a wise 

 liberality, secondary hydrographic scientific problems, mainly of 

 interest to the biologist and geologist, have been connected with 

 the work of the United States Coast Svu'vey, while sections 

 were carried on across the Gulf Stream under the direction of 

 Lieutenant Craven in 1855, and subsequently under that of 

 Lieutenants Mafifitt, Murray, Sands, Bache, Davis, and others. 

 Ill 1850 the extended biological survey of the Florida reefs by 

 Professor L. Agassiz was undertaken at the request of the U. S. 

 Coast Survey. The beginning of a more systematic deep-sea 

 exploration was made by Pourtales and Mitchell, assistants of 

 the U. S. Coast Survey, in 1867. During the explorations 

 of Pourtales of that year, and of 1868 in the " Corwin " and 

 " Bibb," dredging operations were carried on between Florida 

 and Cuba, and a depth of 850 fathoms was reached. The 

 collections were most interesting, and the first publications 

 of the results of the corals and echinoderms by L. F. Pour- 

 tales and A. Agassiz showed as clearly as possible the antique 

 character of the fauna then discovered, and the relationship 

 which it indicated to the cretaceous period, rather than to the 

 animals living upon the adjoining shores. An immense number 

 of new types were also discovered, and it became very plain that 

 the fauna living on the bottom along the course of the Gulf 

 Stream was one of the most interesting known to science. 



The character of the bottom samples also first showed to 

 Agassiz that the deposits going on at the bottom of the ocean, 

 at great depths, were very different from the shore deposits 

 which as a general rule characterize all geological formations ; ^ 

 and that the modern chalk was not very different probably from 

 the old chalk of the cretaceous period. The expedition of the 

 United States Coast Survey steamer " Hassler," Commander 

 Johnson (1871), which sailed with Professor L. Agassiz from 

 Boston to San Francisco, did not fulfil the expectations of its 

 projectors. 



1 Among the earlier publications re- France et des Mers principales du Globe, 

 lating to the nature of the oif -shore hot- Paris, 1871. 

 torn, see Delesse, Lithologie des Mers de 



