312 ANNUAL OF SCIENTIFIC DISCOVERY. 



in relation to the habits of the coral must be noted in this connection namely, 

 that it only exists in clear water. 



To sum up the foregoing in a few words, the theory under consideration 

 is this which was illustrated at length by a diagram. When the stream, m 

 sweeping around the point of Florida, had parted with so much of its sedi- 

 ment as to bring the bottom within 60 or 70 feet of the surface, it became 

 possible for the coral to exist, providing it could find water of sufficient 

 purity. This would be the case at any point so far from the shore as to be 

 beyond the influence of the surf's disturbance of the mud deposited along the 

 coast, as the shoal has risen into the clear surface stratum of the stream. As 

 the bottom formed by deposit is necessarily formed upon a slope, the coral 

 would find a line parallel to the shore, along which none of the conditions of 

 its existence would be wanting. This line would be that of a reef. How the 

 reef would become a line of keys, and the keys in turn become the coast, and 

 the shoal water within become the Everglades, lias already been shown. Did 

 not the island of Cuba interpose, this extension of Florida might go on indefi- 

 nitely, but as the passage narrows, the force of the current necessarily 

 increases, and there is therefore no hope that in this manner Cuba will be 

 annexed. The laws regulating the deposition of sediment also afford an 

 explanation of the long parallel ridges on the sea bottom of the coast of South 

 Carolina, in the bed of the Gulf Stream. Suppose that two or three sub- 

 merged peaks in the line of the Bahama Islands stand within the Stream. 

 Behind these peaks there must be still waters, or at least an eddy. Here 

 matter will be deposited by the waters passing over and beside them, and 

 the matter thrown down will in turn offer an obstacle which will continue to 

 caus-e the effect further and further away from the original point. Again, 

 while the Gulf Stream is moving in a curve around the point of Florida, 

 nearly all its deposits will be made on the riverside of the curve, that is upon 

 this point ; but after passing into the open sea, it takes a straight course and 

 begins to deposit upon both sides alike. Hence, by this theory, the origin of 

 the Bahama Banks. Another very curious result of all this reasoning remains 

 to be mentioned. As the limits of a channel narrow, the current necessarily 

 increases its velocity. The heat of a warm current is therefore retained to a 

 far greater distance from the point of departure. It is well known that the 

 Gulf Stream affects favorably the climate of the north-western portions of 

 Europe. There is nothing then absurd in the idea that during the decrease 

 of the breadth of the Gulf Stream between Cuba and the main land opposite, 

 a decrease of hundreds of miles, the temperature of the water carried across 

 the ocean to the coasts of Ireland, Scotland, and Norway, has been constantly 

 rising, and that from this cause an increasing amelioration of the climate of 

 that part of the Eastern continent has resulted. 



ON THE PERMIAN AND TRIASSIC SYSTEMS OF NORTH CAROLINA. 



At the Albany meeting of the American Association, an interesting and 

 valuable paper was presented by Dr. Emmons, State Geologist of North 

 Carolina, on the Permian and Triassic systems as developed in that state. 

 The Permian rocks in North Carolina are sandstones, slates, and shales, which 



