l66 NEW YORK STATE MUSEUM 



easterly basin. The diastrophic movements, which raised the Green 

 and Taconic mountains, have not only intensely crumpled and 

 folded this entire mass, but also shoved it a great distance westward 

 until it has overridden the western set of formations to within a 

 few miles of Saratoga. 



The combined effect of this great overthrusting of the eastern 

 shale masses on the western set of formations has evidently been 

 that the limestones of the latter have been buried under an immense 

 mass of shales. At Mechanicville, for instance, only a few miles 

 from the western edge of this shale mass, a well was sunk 1400 

 feet through these shales without reaching their bottom. Further, 

 this mass undoubtedly forced the western set of rocks downward, a 

 process which was helped by step faults such as occur at Saratoga 

 farther west. 



We thus get a set of limestone and sandstone formations that 

 descends gradually eastward to greater and greater depths, be- 

 coming all the time buried under greater masses of impervious 

 shales. The mineral waters, which for good reasons are considered 

 as coming from the east, find thus a channel in the jointed and 

 broken limestones and porous sandstones, gradually rising west- 

 ward until they strike the Precambric block at Saratoga, where they 

 rise along the Spring fault and through the relatively thin shale 

 cover to the surface from the storage basin that is formed in the 

 fault block upon which the eastern part of Saratoga Springs stands. 

 This underground course of the water is indicated in the sections 

 on plate of sections by the blue line. 



The pressure necessary to bring the waters on the long journey 

 from the east through this underground channel is probably sup- 

 plied through the head obtained from the mountain regions in the 

 east. 



It is not intended to explain the origin of the carbonated min- 

 eral waters by the structure of this basin, although the possibility 

 may be suggested that the limestones may in their eastward 

 descent reach such depths that they may become subject to meta- 

 morphism through which the carbonic acid and some of the salts 

 become dissociated. At any rate, the known regional metamorphism 

 of the rocks of the eastern trough in the Taconic-Green mountain 

 regions is a fact worth remembering in this connection, and the 



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