332 CONNECTION OF THERMAL SPRINGS IN VIRGINIA 



axis, and in the third it issues from rocks, presenting a great in- 

 version, accompanied by a fault. 



The Warm Sprin^-s rise to the surface through fissures, in a 

 massive bluish limestone, a part of Formation II, of the Virginia 

 and Pennsylvania Reports, and corresponding to the Black river 

 limestone of the New York geologists. This rock forms the sur- 

 face of a long and naiTow anticlinal valley, extending from beyond 

 the Gap Spring (Section III) to the neighborhood of the Falling 

 Spring, (Table I, No. 15,) a distance of about thirty miles, nearly 

 in a direction from northeast to southwest. Beyond this, towards 

 the northeast, the higher formations close over the limestone, form- 

 ing a lofty unbroken mountain, in the prolongation of which the 

 axis gradually dies out. A similar though more rapid change 

 terminates the axis at the southwest, its entire length being about 

 sixty miles. 



The rocks on the northwest side of this axis, forming the Little 

 AVarm Spring mountain, are in general either vertical, or over- 

 turned, while those on the southeast, constituting the lofty and 

 massive range of the Warm Spring mountain proper, present a 

 moderate southeastern dip, excepting at a few points where the 

 inclination for a short distance is much steeper.* The line of 

 thermals situated in this axis, includes those of Table I, from 1 

 to 15, inclusive. Of these, the least thermal, the Gap Spring and 

 Falling Spring, are found towards the extremities of the anticlinal 

 valley ; those nearer the centre of its length, the Warm Springs 

 and Sweet Alum Springs, have a much higher temperature, and 

 the Hot Springs, occupying a central position, are the warmest of 

 all. At the latter point, the flexure of the strata appeal's to have 

 attained its maximum, and is of the folded kind, the rocks of the 

 northwest side of the valley, and of the Little Warm Spring moun- 

 tain, being inverted for a thickness of about three thousand feet. 



The amount of water issuing from these springs is so great as 

 to form the chief part of the Warm Spring creek, Cedar creek, 

 and other streams flowing out of the valley towards the north- 



* This unusually steep inclinatioa on the southeast side of the axis, is seen opposite the 

 Warm Springs on the main road. 



