GEOLOGY OF SARATOGA SPRINGS AND VICINITY l6^ 



RELATIONS OF THE SARATOGA MINERAL SPRINGS TO THE 

 STRUCTURE OF THE SHALE BELT OF THE UPPER HUDSON 

 VALLEY. 



BY R. RUEDEMANN 



The study of the shale belt of the Saratoga and Schuylerville 

 quadrangles by the writer has brought out certain structural feat- 

 ures which appear to explain the accumulation of the mineral 

 waters in the Saratoga region. 



The salient facts in the distribution of the mineral water for the 

 discussion here presented are : (i) the mineral springs are dis- 

 tributed in a belt extending in a northeast-southwest direction, 

 from the Gurn spring to Ballston Spa and farther south (Albany?) ; 

 (2) the waters come up in connection with or near a fault line, 

 extending in this direction: (3) the water does not occur west of 

 this fault line, but is found far to the east of it (Quaker spring 

 and \'ita spring) ; (4) it is stored in a series of limestone, dolomite 

 and sandstone formations underlying a shale formaton. 



The investigations of the writer have now shown that the shales 

 forming the surface rocks east from the springs fault belong to two 

 entirely different series or sets of formations which were deposited 

 in two separate basins. 



The western set begins on top with the Canajoharie shale. This 

 is underlain by the Glens Falls and Amsterdam limestones, the 

 Hoyt limestone. Little Falls dolomite and Potsdam sandstone, the 

 latter resting on Precambric rocks, mostly gneiss. 



This western series, which sinks in one or two step faults from 

 the Precambric area of the Adirondacks to the level of the Saratoga 

 plain, is but little disturbed and the beds are but little tilted and not 

 folded. It continues eastward to an unknown extent, which, how- 

 ever, must be considerable since only the western edge of the old 

 basin is now exposed on the surface. Undoubtedly it extends as 

 far as the eastern hill region, as indicated in sections. 



Only 3 miles east of Saratoga an entirely different set of forma- 

 tions begins to appear on the surface. In this set most formations 

 are represented by shale, namely, the Trenton by the Snake Hill 

 shale, the Chazy by Normanskill shale, the Reekmantown by Bald 

 Mountain limestone (thin), Deep Kill shales (thick) and Schaghti- 

 coke shale, and the Cambric by the Georgian shales, slates, lime- 

 stones and quartzites. This set of formations, as their lithologic 

 character and faunas show, has been formed in another more 



