BATHYMETRICAL DISTRIBUTION. 63 



tween the latitudes of Cape Canaveral and Savannah. The specimens 

 are all broken and worn and associated with Foraminifera remarkably 

 clean and free from mud. The indications are that a current sweeps 

 over the bottom in a direction from south to north : in other words, the 

 Gulf Stream extends to the bottom at least as far north as the highest 

 latitude mentioned, and is not underlaid by a cold arctic current running 

 in opposite direction, as has sometimes been assumed to account for the 

 low temperature at the bottom. We know that the corals enumerated 

 above (with the exception of Diphhelia profunda, which 1 have never 

 found alive) live on the coast of Cuba and Florida hi depths not less 

 than 100 fathoms, and are thus out of reach of transportation by 

 superficial agencies. 



A possible nearer habitat would be the northern extremity of the 

 Bahama Banks, between latitudes 27° and 28°, and perhaps somewhat 

 farther north on the extension of the banks which is known to exist on 

 the eastern border of the Gulf Stream ; yet even in this case the trans- 

 portation would be in the same direction. We have positive evidence 

 of the depth to which the current extends in the straits, in the experi- 

 ment of Assistant II. Mitchell. United States Coast Survey, whose 

 conclusion is. "that the Gulf Stream has " nearly uniform velocity and constant 

 course for a depth of fix hundred fathoms, although its temperature varies in 

 tins depth 4() Fahrenheit." (See Report of the Superintendent United 

 States Coast Survey for 1867, pp. 170- 179.) 



