GEOLOGY. 271 



In the course of the operations, two distinct salt strata were gone 

 through, at 222 and 1240 feet depths, with the respective temperatures 

 of 50 and 66 F., and 1| and 2i per cent, of salt. 



ARTESIAN WELL AT CHARLESTON, S. C. 



THE artesian well at Charleston, S. C., has attained a depth of 

 952 feet ; the last 19 feet perforated were through a stratum of argilla- 

 ceous slate, intermixed with granite boulders. This depth is not ex- 

 ceeded by any similar work in this country. The temperature here, 

 as well as in other parts of the world, has been found to increase grad- 

 ually as we proceed downwards. Experiments made with the self- 

 registering thermometer, under the direction of Mr. F. S. Holmes, 

 show the average temperature at the present depth to be at least 

 82i F. The mean temperature at the surface is 65 F. This in- 

 crease is not altogether uniform with the results obtained in the arte- 

 sian well near Paris. There the depth is 1,800 feet, and the mean 

 temperature at the bottom, 83 F. ; at the surface, 51. 1. The 

 bore of the well at Charleston havirig been found to be too small, the 

 workmen are now engaged in enlarging it, to nearly double its former 

 dimensions. At the meeting of the American Association in Charles- 

 ton, Mr. Holmes exhibited numerous specimens of fossil Foraminiferee 

 obtained during the excavations, which far exceed in size any at pres- 

 ent living upon our coasts. Editors. 



ON THE ORIGIN OF SALT AND SALT LAKES. 



AT a meeting of the Boston Society of Natural History, Prof. H. 

 D. Rogers presented a communication on the origin of salt and salt 

 lakes. He thought that there was an intimate connection between 

 the present basins of salt water and the existing distribution of the 

 earth's climates, a connection which, fully established, 'promises to 

 afford us. through a tracing of the distribution of the ancient saliferous 

 deposits, much insight into the climates of the earth in the past peri- 

 ods. A sound geological theory teaches that the original source of 

 the salt of the ocean, and of all the salt lakes, was in the chlorides of 

 the volcanic minerals and rocks of the earth's crust. The action of 

 the descending rain is to decompose these rocks, and to dissolve and 

 float away into the receptacle of the sea the soluble salts which they 

 contain. The geological revolutions shifting at successive times the 

 waters of the ocean from their bed, have laid dry a portion of the sedi- 

 ments, leaving behind a part of the sea-water to be evaporated, thus 

 impregnating the strata with its saline ingredients. Thus we find, 

 that all the marine deposits, however far removed at present from any 

 ocean, contain an appreciable quantity of sea-salt. The amount of 

 salt in the ocean, if spread over the dry land, would form a stratum 

 several feet thick over the whole surface. 



Prof. Rogers considers, that all salt basins must have been Gas- 



O ' 



pians, seas without outlets, where the dissolved salts have been stored 

 up ; all such seas are more or less saline. As the Caspian Sea is 



