324 CONNECTION OF THERMAL SPRINGS IN VIRGINIA 



With the oxcoption of brief and rather incidental notices pub- 

 lished by myself and others, and the communications of Dr. 

 Danbeny to Sillinian's Journal and the Ashmolean Society, no 

 account has yet been given of the peculiarities of geological struc- 

 ture, associated with the thermal springs of the United States. 

 Indeed, the supposed rareness of their occurrence in this country, 

 compared with many parts of Europe, and their comparatively 

 slight excess of temperature in most instances over the ordinary 

 springs, have naturally rendered them less inviting as subjects of 

 observation. It is hoped, however, that the details about to be 

 presented, by proving their frequency in a part of the Appalachian 

 chain, in which until of late years only a few were believed to 

 exist, will encourage a search for them in other parts of this ex- 

 tended mountain belt. 



My objects in the present communication ^re first, to call atten- 

 tion to the xevy frequent occurrence of thermal springs among the 

 axes of the Appalachian chain in Virginia ; secondly, to indicate 

 certain laios of position, by which I have found them to be gov- 

 erned, and thirdly, to point out the important bearings of those 

 facts when connected wdth the peculiar geology of the region, 

 upon the theory of a generally diflYised internal heat. 



According to the views of Professors Daubeny and BischofF, 

 every spring is to be regarded as T/iermal, whose tcmperatiu"e 

 exceeds the atmospheric mean of the region in which it is situ- 

 ated : and in conformity with this definition, the former of these 

 philosophers has proposed, " in constructing a scale of temperature 

 in regard to them, to calculate it not by their actual warmth, but 

 by the degree of their excess above the mean of the climate." 

 The propriety of this suggestion, which he has himself earned 

 into execution in the very valuable Table appended to his ' Report 

 on Mineral and Thermal Waters,' is obvious upon a moment's 

 consideration. Thus we know, that the ordinary superficial 

 springs under the equator have a temperature as high as some of 

 the celebrated thermal waters of Europe and America. In Mexico 

 the temperature of seventy-two degrees, corresponding with the 

 mean of the climate, belongs to the common pj)rings, while in 

 Virginia 'the same temperature renders decidedly thermal the 



