GEOLOGY. 301 



62; 22nd, limestone, 134; 23rd, shale, 70; 24th, limestone, 20; 25th, 

 shale, 56 ; 2 6th, limestone, 34 ; 27th, white soft sandstone, 15 feet. 



The well was first commenced as a cistern. From the surface of the 

 ground, where it is fourteen feet in diameter, it has a conical form, 

 lessening at the depth of thirty feet to a diameter of six feet. Thence 

 the diameter is again lessened to sixteen inches, until the depth of 78 

 feet from the surface is attained. From that point it is diminished to 

 nine inches, and this diameter is preserved to the depth of 457 feet. 

 Passing this line the diameter to the present bottom of the well, is 

 three and a half inches. 



The lowest summer stand of the Mississippi river is passed in the first 

 stratum of the shale, at the depth of twenty-nine or thirty feet from 

 the surface. The water in the well, however, is always higher than 

 the water line of the river, and is not affected by the variations of 

 the latter. The first appearance of gas was found at a depth 0^066 

 feet, in a strata of shale one and a half feet thick, which was strong- 

 ly imbued with carbonated hydrogen. When about 250 feet below 

 the surface of the earth at the beginning of a layer of limestone, the 

 water in the well became salty. 



The level of the sea reckoned to be five hundred and thirty-two 

 feet below the city of St. Louis was passed in the same layer ; two 

 hundred feet lower still, in a bed of shale, the water contained one- 

 and-a-half per cent, of salt. At a depth of 950 feet, a bed of bitumi- 

 nous marl 15 feet in diameter was struck. The marl nearly resembled 

 coal, and on being subjected to a great heat, without actually burning, 

 lost much of its weight. In the stratum of shale which followed, the 

 salt in the water increased to two-and-a-half per cent. The hard 

 streak passed, a bed of chert, was struck at a depth of 1,179 feet from 

 the surface, and going down 62 feet. In this layer the salt in the wa- 

 ter increased to full three per cent. The boring at present is, as ap- 

 pears by the statement above, in a bed of white soft sand rock, the 

 most promising that has yet been struck for a supply of water such as 

 is wanted. 



Observations have been made with a Celsius thermometer of the 

 temperature of the well. At the mouth of the orifice, the thermome- 

 ter marks 50 degrees ; at the depth of 45 feet, the heat is regular, 

 neither increasing nor diminishing with the variations above, and at 

 the distance of 351 feet, the heat has increased to 60 degrees. 



ON THE EFFECT OF THE RECLAMATION OF THE ANNUALLY IN- 

 UNDATED LANDS OF THE MISSISSIPPI VALLEY UPON THE 

 GENERAL HEALTH OF THE COUNTRY AND THE NAVIGATION 

 OF THAT RIVER. 



The following report was presented at the Cleveland meeting of 

 the American Association, by Andrew Brown, Esq., of Natchez, 

 Miss. 



At a meeting of this Association, held at Philadelphia,. 1848, your 

 Committee on the Mississippi river, reporting their investigations of 



