lO NEW YORK STATE MUSEUM 



BRIEF STATEMENT OF THE LOCAL GEOLOGY 



The careful work of Professor Ciishing and Doctor Ruedemann 

 lias established the following section of the strata at Saratoga 

 Springs, from above down : 



The Canajoharie shales (formerly called the Hudson River 

 or sometimes the Utica slates). Of unknown but great 

 thickness. 

 The Amsterdam limestone (formerly called the Trenton lime- 

 stone) 5^' 



A very important erosion interval represented in the Cham- 

 plain valley by the Chazy limestone 300 feet thick, and 

 the upper part of the Beekmantown (formerly called the 

 Calciferous sandrock) 1200 feet. Land conditions seem 

 to have prevailed in the Saratoga region. 

 Little Falls dolomite (the lower member of the Beekmantown 



or Calciferous) 300'+ 



Hoyt limestone (formerly called the Saratoga limestone) ... icmd' 



Theresa passage beds, alternate limey and sandy layers 50-75' 



Potsdam sandstone or quartzite 200' or less 



Grenville series of ancient gneisses and metamorphic rocks 



with intrusive igneous masses Lidefinitely thick 



Exclusive of the shales or slates at the top, which are above the 

 productive horizon of the mineral waters, we have thus about 500 

 feet of limestones and dolomites, resting upon 200 feet or less of hard 

 sandstones, and these upon the ancient metamorphosed gneisses, 

 granites etc., which were formerly collectively described as Lauren- 

 tian or Archean, 



When tapped by the drill the mineral waters are chiefly obtained 

 from the Little Falls dolomite. When the drill has penetrated the 

 slates it strikes the waters, if such are found at all, in limestones, 

 not far below the underside of the slates. It is possible that in 

 some instances this may be in the Amsterdam (or old Trenton), 

 but where the drill cores or the drillings have been identified, it 

 is easy to recognize them as belonging to the Little Falls dolomite. 

 The drilled wells in Saratoga Springs itself start either in the slates 

 or in the Amsterdam (Trenton) limestone, but quickly pass through 

 one or both of these and enter the Little Falls dolomite. In the 

 Congress diamond drill core, which has been preserved and is 

 available for study, the following section was disclosed : 



