ORIGIN OF BRINE SPRINGS. 121 



have had this form impressed upon them by a very small admixture of that substance. Thus 

 it is known that when a small portion of solution of sulphate of iron is added to a solution of 

 alum, and the whole allowed to crystallize, the sulphate of iron assumes the octahedral form 

 of the alum, although these octahedral crystals contain scarcely a trace of the latter salt. . As 

 igneous action was probably concerned in the consolidation of this rock, it is in perfect accord- 

 ance with the above fact to suppose that the crystalline form of this clay may have been de- 

 rived from a small portion of salt which <hey formerly contained. It is certain that this clay 

 is composed of carbonate of lime, silica, alumina and oxide of iron, but does not contain a 

 trace of common salt.* Its occurrence, therefore, cannot be considered of sufficient importance 

 to warrant the conclusions which have been drawn from it concerning the origin of the brine 

 springs. 



Several years since I ventured to assert, as the result of an examination of the Onondaga 

 springs, that the most plausible theory was, that they originated from a solution of beds of 

 fossil salt.t This opinion, although quite generally adopted by those who are most familiar 

 with the history of these springs, was nevertheless opposed by some individuals for whose 

 views on subjects of this nature I entertain the highest respect, and I therefore feared that the 

 grounds upon which it rested were insufficient. But after the most careful review of the 

 subject, I have again been brought to the conclusion, that of all the theories which have been 

 proposed to account for the formation of these spririgs, there is none so free from objection 

 as that which ascribes it to the solution of beds of fossil salt. 



I will now briefly state some of the facts which favor this view, and notice some of the objec- 

 tions which have been urged against it. In the outset, however, it should be observed that most 

 of them are applicable to the immediate vicinity of the Onondaga springs ; nor does it follow 

 as a matter of course, that if fossil salt exists in their vicinity, it must necessarily be found 

 near all the brine springs of the western region which have been enumerated. There are many 

 instances of the occurrence of brine springs in England and France, at a considerable distance 

 from any hitherto discovered bed of salt ; and it is only when the brine has attained a certain 

 degree of strength, that this mineral is to be looked for in the immediate vicinity. 



A boring was made several years since at Vic, in the very centre of the saline district, in 

 the department of La Meurthe, in France. They first passed through strata of freestone and 

 clay, intersected by veins of sulphate of lime. At the depth of about fifty metres,J the clay 

 and sulphate of lime which the borer brought up, began to be mixed with rock salt, and con- 

 tinued so till about the sixty-fifth metre, at which the bed of rock salt began. 



The account adds, that at the present time (September 1819), the boring has reached to 85 

 metres ; thus passing through more than twenty metres of salt, divided into three beds by the 

 thin strata of sulphate of lime, and the borer continues to bring up salt. 



 



 There is a elay found in the immediate vicinity of this cry^allized stratum, which is often incrasted with crystals of sulphate 

 of magnesia. A specimen which I analyzed, contained ia^ addition to the carbonate of lime, silica, alumina and oxide of iron, 

 about twenty per cent, of carbonate of magnesia. 



t New- York Mudkal and Physical Journal, V. 176. t A metre is about 39.37 English inches. 



Part I. 16 • 



