1052 KEPORT OF COMMISSIONER OF FISH AND FISHERIES. [8] 



this is often almost entirely abseut, even iu 300 to 5'JO fathoms. The 

 sand, however, is often so fine as to resemble mnd, and is frequently so 

 reported when the preliminarj- souudiugs are made and recorded. In 

 many instances, even in our deepest dredgiiigs (over 700 fathoms), and 

 throughout the belt examined, we have taken numerous pebbles and 

 small rounded bowlders, of all sizes, u]) to several pounds in weight, 

 consisting of granite, syenite, mica-schist, etc. These are sometimes 

 abundant and covered with Actiniw, ete. Probabl}^ these have been re- 

 cently floated out to this region, while frozen into the shore-ice, in win- 

 ter and spring, from our shores and rivers, aud dropped iu this region, 

 where the ice melts rajndly under the influence of tbe warmer Gulf 

 Streaui water. Possibly much of the sand, esi)ecially the coarser por- 

 tions, may have been transported by the same agency. Another way, 

 generally overlooked, in which fine beach sand may be transported long 

 distances, is by reason of its floating on the surface of the water after 

 it has been exposed to the air on the beaches and dried. The rising 

 tide always carries off" a certain amount of tine dry sand floating in this 

 way. In our fine towing nets we always take more or less fine siliceous 

 sand, which evidently was floating on the surface, even at considerable 

 distances from the shore. 



The i^revalence of fine sand along the Gulf Stream Slope in this re- 

 gion, and the remarkable absence of actual mud or clay deposits indi- 

 cato that there is here, at the bottom, sufficient current to prevent, for 

 the most part, the deposition of fine argillaceous sediments over the 

 upper i)ortion of the slope, in 65 to 150 fathoms. Such materials are 

 probably carried along till they eventually sink into the greater depths 

 nearer the base of the slope or beyond, in the ocean basin itself, where 

 the currents are less active. It is probable that such a movement of 

 the water may be partly due to tidal currents, as well as to the actual 

 northward flow of the Gulf Stream, which is here slow, even at the sur- 

 face.* It is not probable, however, that the bottom currents are strong 

 enough to move even the fine sand after it has once actually reached 

 the bottom ; nor is it stroiig enough to inevent the general deposition 

 of oceanic foramiuifera, pteropods, etc. I have above suggested that 

 the loose nodules of limostoue may have bewn derived from softer rocks 

 or unconsolidated materials by the removal or wearing away of the 

 latter. The existence of actual currents sufficiently powerful to directly 

 effect such erosion is not supposable. I believe, however, that such a 

 result may be due directly to the habits of certain fishes and Crustacea 



* Our observations fully demonstrate that the western edge of the Gulf Stream is 

 nearer the coast than it has hitherto been located on the charts. In summer, as is 

 well known, it is nearer the coast than in winter, but this doubtless applies strictly 

 to the surface water. Our researches show that the warm belt iu 65 to 125 fathoms is 

 iuhabited by a peculiar southeru fauna that could not exist there if the Gulf Stream 

 did not iiow along this ai'ca at the hotfom both iu winter aud summer. But it is evident 

 that what many of these species require is not a very high but a nearly uniform, tem- 

 perature. Such an equable temperature cannot exist in this region except under the 

 direct aud constant influence of the Gulf Stream. 



