■^0^ 14. — (Letter No. 3.) To Carlile P. Patterson, Superin- 

 tendent United States Coast Survoj, Washinyton, D. C, from- 

 Alexander Agassiz, on the Dredging Operations carried on from 

 December, 1878, to March 10, 1879, hy the United States Coast 

 Survey Steamer " Blake" Commander J. R. Bartlett, U S. N. 



(With two maps.) 



I JOINED the "Blake" at Washington, on November 27, 1878, for a 

 second dredging cruise. According to your instructions, we intended to 

 proceed to Nassau, and there devote a few days to dredging and sound- 

 ing, in order to trace the connection between the fauna of the northern 

 extremity of the Bahama Banks and that of the Straits of Florida. Owing 

 to rough weather this was not deemed prudent, and we were compelled 

 to put into St. Helena Sound, and, for the same reason, when off 

 Jupiter Inlet, instead of crossing the Gulf Stream ' to make Nassau, it 

 was thought best to put in to Key West. From there, when the 

 weather moderated, we started for Kingston, Jamaica, calling at Havana 

 for the purpose of making a couple of hauls on the Pentacrinus ground 

 discovered by Captain Sigsbee off Morro Light. We made two casts of 

 the dredge in 175 to 400 fathoms, and obtained a few specimens of 

 Pentacrinus. We kept on along the northern shore of Cuba, through 

 the Old Bahama Channel, without stopping to sound or dredge, Mr. 

 Pourtales having, in former years, dredged and sounded, in the " Bibb," 

 Acting Master Piatt, U. S. N., over the greater part of this line. 



At the eastern end of the Old Bahama Channel we ran a line of 

 dredgings and soundings across from Caya Cruz to Lobos Light. In the 

 deepest part of the channel we found only 500 fathoms, although the 

 hydrographic maps indicated 900 fathoms, no bottom. This is an excel- 

 lent example of the uncertainty of the old method of sounding with 

 hemp rope, even in moderately deep water, when there is a strong cur- 

 rent, such as we found here. 



Nothing of special interest came up in any of the casts made either 

 with the trawl or dredge. Wound around the steel-wire rope on this 

 line, however, we found a few pieces of the deep-sea Siphonophores 

 (Rhizophysa), described lately by Studer in the Zeitschrift f. wissen. 

 Zoologie. Subsequently we frequently found more or less complete 

 specimens of these Siphonophores, generally entangled on the wire rope 



