GEOLOGY. 175 



THE ONTARIO SALT REGION. 



The existence of a salt-bearing horizon known as the Onon- 

 daga or Salina formation, in the Silurian series in New York, 

 between the Niagara and Lower Helderberg limestones, has 

 long been recognized. The brines of Syracuse and its vicin- 

 ity are, however, obtained not directly from this formation, 

 but from an ancient gravel which fills an old lake-basin ex- 

 cavated on the outcrop of this formation ; and the existence 

 of rock-salt at this horizon was not demonstrated. In 1866, 

 however, Hunt described the occurrence of rock-salt, detected 

 in a boring at Goderich, Ontario, on the east shore of Lake 

 Huron, and expressed the opinion that the deposit occupied 

 a position identical with that which supplies the brines of 

 Syracuse. In 1876 a boring to explore this salt was made 

 at Goderich with a diamond drill to the depth of 1517 feet 

 in horizontal strata, and from the cores he has been enabled 

 to study the geology of this deposit. The Oriskany sand- 

 stone and the Lower Helderberg limestone, which are found 

 in Eastern New York above the Salina formation, are here 

 wanting, and the superficial strata at and near Goderich have 

 been regarded by the geological survey of Canada as the 

 base of the Upper Helderberg or Corniferous limestone. 

 The salt was reached at a depth of 997 feet, beneath which 

 were found 520 feet of red and brown marls, alternating with 

 beds of anhydrite and rock-salt, the boring having been dis- 

 continued without reaching the base of the formation. Six 

 beds of salt were met with, the thickest two being about 

 thirty-one and twenty-five feet the latter exceedingly pure. 

 Above the rock-salt are still 121 feet of variegated marls, 

 making in all 641 feet, followed in ascending order by 243 

 feet of dolomites with gypsum, making 884 feet supposed to 

 belong to the Salina formation. To this succeed 276 feet of 

 limestone, with layers of chert and with fossil corals; and, 

 finally, 278 feet of dolomites like those below the limestone, 

 but without gypsum. The organic remains of the limestone, 

 so far as can be ascertained from the cores ^ot in boring, re- 

 semble those of the Upper Helderberg, from which, however, 

 they are separated by nearly 300 feet of dolomites, resem- 

 bling those of the underlying Salina series, and perhaps cor- 

 responding to the Water-lime beds of New York. It is sug- 



