76 ARTESIAN WELLS. [CHAP. XXV. 



polls, and at Arcola, where they contain hippurites and other char 

 acteristic fossils. The depth to which they have sunk Artesian 

 wells through them in many places (between 500 and 1000 

 feet), is astonishing. One boring through blue marl and lime 

 stone at Erie, in Greene County, was 469 feet deep, and the well 

 yielded 350 gallons of water per minute at the surface. The 

 water rises forty feet above the surface, and can be made to reach 

 fifty feet, though in diminished quantity. Here, as in Europe, 

 the temperature of the earth s crust is found to increase as we 

 descend, the water being sensibly warmer than that of the air, so 

 much so that in cold weather it sends forth steam. Each new 

 excavation at Erie robs the wells previously bored of part of 

 their supply. The auger with which they perforate the soil is 

 four inches in diameter, and the average cost of excavation sixty- 

 two cents, or about 2s. 6d. per foot, for the whole depth of 469 

 feet. No solid rock has been pierced here, the strata consisting 

 throughout of soft, horizontally stratified blue limestone. They 

 have also pierced these same rocks, at a distance of three miles 

 from. Demopolis (a town situated at the junction of the Tom- 

 beckbee and Black Warrior rivers), to the depth of 930 feet 

 without gaining the water, yet they do not despair of success, as 

 sand has just been reached. 



At Arcola, the proprietor presented me with several creta 

 ceous fossils, and some irregular tubular bodies, the origin of 

 which he wished to have explained. I immediately recognized 

 them as identical with the vitreous tubes found at Drigg, in Cum 

 berland, in hills of shifting sand, which have been described and 

 figured in the Transactions of the Geological Society of London.* 

 They have a glazed and vitrified interior, and bodies of similar 

 form and structure were first supposed by Saussure to have been 

 due to the passage of lightning through sand, a theory now gen 

 erally adopted. 



If any geologist retains to this day the doctrine once so popu 

 lar, that at remote periods marine deposits of contemporaneous 

 origin were formed every where throughout the globe with the 

 same mineral characters, he would do well to compare the suc- 

 # Vol. ii. p. 528, and vol. v. p. 617, 1st series. 



