270 REPORT OF NATIONAL MUSEUM, 1904. 



limestone, and that carbonic- acid holds its base (the lime) with a tenure 

 more feeble than that of the common acids; consequently he argued 

 that when muriatic, sulphuric, or nitric acid comes in contact with 

 limestone, it is immediately decomposed. 



We have vast quantities of muriate of lime in our wells, springs, etc., which is a 

 very soluble salt. If nature has now, or formerly had, any method for present- 

 ing large quantities of muriatic acid to the lime rocks, they would of course be 

 reduced to that soluble salt with great rapidity. Lime rocks would lie rapidly dis- 

 solved, leaving valleys between those rocks which are subject to the ordinary disin- 

 tegrating agents only. The valleys of Adams, Williamstown, Little Hoosick, etc., 

 which are situated on limestone, could then be satisfactorily explained. If the com- 

 mon opinion that the ocean has stood over our continent be received as true, we 

 have only to add one more conjecture to make out the requisite supply of muriatic 

 acid; that is, we must suppose that the ocean at that time contained an excess of 

 that acid. 



In spite of admonitions by Van Rensselaer, Eaton insisted in indulg- 

 ing in a theorizing propensity, although he would not acknowledge it 

 by this name, claiming that he but traced ""a few of nature's footsteps 

 where the impressions still remain entire." Finding large and small 

 masses of what he designated as calciferous sandstone, metalliferous 

 limestone, and graywacke, which properly overlie the slate, actually, 

 as he thought, embedded in it, where the rocks were exposed, as at 

 Cohoes Falls, he would argue that these masses fell in between the 

 slate lamina 1 while the latter were in a semi-indurated state. 



Eaton noted the probable difference in age between the red sand- 

 stones of the Connecticut Valley and of the Catskill Mountains, which 

 latter he rightly considered to belong to the old-red or Devonian forma- 

 tions. In discussing the Saliferous rock occurring near Little Falls 

 and extending to the west end of Lake Ontario in upper Canada, and its 

 economic importance, he was disposed to argue that the brine springs 

 issuing from the same were what he called "the daily productions of 

 nature's laboratory." "We see, 11 he wrote, "the sulphur in iron 

 pyrites taking oxygen from water, and thereby becoming sulphuric 

 acid; we then see it uniting with magnesia, which is diffused in rocks, 

 and thus forming Epsom salts. * * * We are all familiar, too, 

 with the process of nature by which alum and copperas are made. 

 Why ma} T we not suppose that the two constituents of common salt 

 (muriatic acid and soda) are in some state of combination in the rocks 

 of the salt district, and that by some of those double decompositions 

 with which nature is perfectly familiar salt is produced in the liquid 

 state? May not this be the cause of the superior saltness of the brine 

 springs of Salina over those foreign springs which are supposed to 

 proceed from the solution of rock salt?" 



It was in this work that Eaton introduced the name "Calciferous 

 slate" to designate the slaty rock associated with gwpsum and shell 



