198 EEPOET OF NATIONAL MUSEUM, 1899. 



are enabled to form some idea of their extent and thickness. Below 

 is given a smumary of results obtained in boring one of these wells to 

 a depth of 1,517 feet at Goderich, Canada. Beginning at the top, the 

 rocks were passed through in the following order: 



I. Clay, gravel, marls, limestone, dolomite, and gypsum variously 



interstratified 9^7 



II. First bed of rock salt 30 11 



III. Dolomite with marls 32 1 



IV. Second bed of rock salt 25 4 



V. Dolomite 6 10 



VI. Third bed of rock salt 34 10 



VII. Marl, dolomite, and anhydrite 80 7 



VIII. Fourth bed of rock salt 15 5 



IX. Dolomite and anhydrite 7 



X. Fifth bed of rock salt 13 6 



XI. Marl and anhydrite - 135 6 



XII. Sixth bed of rock salt 6 



XIII. Marl, dolomite and anhydrite 132 



Total thickness of formations passed through 1,517 feet. 



Total thickness of beds of salt 126 feet. 



The above section shows that the ancient sea or lagoon underwent 

 at least six successive periods of desiccation, and especial attention 

 is called to the remarkable regularity of the deposits. On the oldest 

 sea bottom (XIII) the carbonates and sulphates of lime and magnesia 

 were deposited first, being least soluble. Then followed the salt, and 

 this order is repeated invariably. The other constituents mentioned 

 as occurring in the waters of lakes and seas are not sufficiently abun- 

 dant to show in the section, or owing to their ready solubility they 

 have been in large part removed since the beds were laid down. 

 Chemical tests, however, reveal their presence. 



Although salt was manufactured from the brine of springs, near 

 Onondaga Lake, in New York, as early as 1788, and has been regu- 

 larly manufactured from the brine of wells since 1798, it was not until 

 subsequent to the discovery of extensive beds of rock salt in the 

 Wyoming Valley, while boring for petroleum, that the mining of the 

 material in this form became an established industry. In June, 1878, 

 a bed of rock salt 70 feet in thickness was found in the valley above 

 mentioned, at a depth of 1,270 feet. Subsequently other borings in 

 Wyoming, Genesee, and Livingston counties disclosed beds at vary- 

 ing depths. In 1885 the first shaft was sunk at Pifford by the Retsof 

 Mining Company, the salt bed being found at a depth of 1,018 feet. 

 Three other shafts have since been sunk, the first about a mile west of 

 the Retsof, the second about 2 miles south of Leroy, and the third 

 at Livonia, in Livingston County. The salt when taken from the 

 bed is stated to be of a gray color, due to the presence of clay, which 

 renders solution and recrystallization necessary when designed for 

 culinary purposes. The thickness of the salt beds and their depth 

 are somewhat variable. The following figures are quoted from 



