^2 NEW YORK STATE MUSEUM 



No one could with much reason attribute the carbonic acid gas 

 to the Northumberland plug itself, but the plug does serve to show 

 the former existence of volcanic action and unless it has been thrust 

 Vv^estward into its present position by some great reversed fault from 

 an original situation farther east, as will be outlined by Professor 

 Gushing, it may be considered significant to this extent. We may 

 at least state that all the other geological features of Saratoga 

 Springs and Ballston Spa are reproduced in many places north- 

 ward throughout the Champlain valley. Practically the same 

 geological section is seen. A great number of faults have been 

 mapped and yet no such mineral springs have ever been discovered. 

 The great quantities of carbonic acid gas in the water are distinctive 

 of the two localities, Saratoga Springs and Ballston. The only 

 other visible and distinctive feature of the Saratoga region as com- 

 pared with the localities farther north is the volcanic plug. One 

 may merely suggest the possibility of some more westerly and deep- 

 seated manifestation of the same sort of activity through whose 

 influence the carbonic acid gas rises through faults to the surface. 

 The tight cover of slates east of the fault may have kept from 

 emergence at the surface the waters in which the gas speedily 

 became dissolved. 



Even sodium chlorid itself has been attributed to volcanic sources. 

 Thus Sir Archibald Geikie, in his Text-book of Geology, 4th ed. 

 1903, 1, p. 269, when speaking of volcanic emissions, states : " Sodium 

 chlorid sometimes appears so abundantly that wide spaces of a vol- 

 canic cone, as well as of the newly erupted lava, are crusted with 

 salt which can be profitably removed by the inhabitants of the 

 district. Gonsiderable quantities of chlorids may be buried between 

 successive sheets of lava, and in long subsequent times may give 

 rise to mineral springs, as has been suggested with reference to 

 the saline waters, which issue from volcanic rocks of old Red Sand- 

 stone and Triassic age in Scotland." Again, on page 469, we find: 

 " Garbonic acid is here and there largely evolved within the earth's 

 crust, especially in the regions of extinct or dormant volcanoes. 

 Subterranean water coming in the way of this gas dissolves it and 

 thereby obtains increased solvent power." Professor L. De Launay 

 of Paris, in a very important work^ upon the Investigation, Dis- 

 covery and Management of Mineral Springs, under the caption 



i L. De Launay, Recherche, Captage et Amenagement des Sources Thermo- 

 Minerales, Paris, Banday et Cie, 1899. 



