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



this is ofteu almost eutirely abseut, oven in 300 to 5u0 fathoms. The 

 sand, however, is ofteu so fine as to resemble mud, and is frequently so 

 reported when the preliminary soundiiiiis are made and reeorded. In 

 many instances, even in our deepest du'dyin^s (over TOO iathoms), and 

 throuj'hout tlu' belt examined, we have taken numerous pebbles and 

 small rounded bowlders, of all sizes, up to several i)0unds in weight, 

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

 abundant and covered with Actinice, etc. Probably these have been re- 

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

 ter and spring, from our shores and rivers, and droi)ped in this region, 

 where the ice melts rapidly under the inllneuce ot the warmer Gulf 

 Stream water. Possibly much of the sand, especially the coarser por- 

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

 geneialiy overlooked, in which tine beach sand may bo 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 tine towing nets we always take i^oreor less fine siliceous 

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

 distances from the shore. 



The prevalence of fine sand along the Gulf Stream Slope in this re- 

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

 cate that there is here, at the bottom, suthcient current to prevent, for 

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

 upper portion of the sloi)e, 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 tine sand after it has once actually reached 

 the bottom ; nor is it strong enough to prevent the general deposition 

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

 the loose nodules of limestone may have been derived from softer rocks 

 or unconsolidated materials by the removal or wearing away of the 

 latter. The existence of actual currents sutticiently powerful to directly 

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

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



*Our ohscvvatioDH fully deinonstrato tliat the western edge of the Gulf Stream is 

 uearor the coast thau 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 unrface water. Our researches show that the warm belt in 65 to 12") fathoms is 

 inhabited l)y a piiculiar southern fauna that could not exist there if the Gulf Stream 

 did not tlow along this area a< //leio'/owi both in winter and summer. 15ut it is evident 

 that what many of these species i-et^uire is not a very high but a nearly uniform tem- 

 perature. Such an equalde temperature cannot exist in this region exce|)t under the 

 direct and constant intlueuco of the Gulf Stream. 



