Notice of the Thermal Springs of North America. 93 



from it, is the breaking out at their foot, near New Madrid, of that 

 tremendous earthqualie, which in 1812, caused the permanent 

 submersion of a considerable tract of land near the Mississippi, 

 now converted into an extensive swamp. Such is the depth to 

 which this tract has been submerged, that nothing but the sum- 

 mits of the trees, I am told, are seen standing above the surface 

 of the stagnant morass. 



A slightly thermal spring which goes by the name of Mud- 

 Creek, exists in the same parallel as that of New Madrid, and at 

 a distance of not many miles from the submerged tract in ques- 

 tion. 



Such are the principal particulars I have been able to bring to- 

 gether, either from personal observation, or from information sup- 

 plied me by others, with respect to the thermal waters existing 

 within the limits of the United States of America. The variety 

 of such phenomena, when the extent of country is taken into ac- 

 count, as well as the unfrequent occurrence of acidulous or carbon- 

 ated waters, might be anticipated from the unfrequency of earth- 

 quakes, the regularity of the rock formations, and the absence of 

 trap rocks from so large a portion of the continent. 



Nevertheless, the occurrence of a few such springs in the midst 

 of the Alleghanies, and elsewhere, seems to show, that volcanic 

 operations are going on in a covert and languid manner, under- 

 neath certain parts of that range. 



To these operations, acting formerly with greater intensity, 

 may perhaps be attributed the uplifting of the chain itself, as well 

 as the vertical and disturbed condition of the strata round about 

 the anticlinal line, whereas at present the same forces only man- 

 ifest their existence by imparting a higher temperature to a few 

 of the springs, which hurt out at this point, and possibly also in 

 causing the emission of volumes of sulphuretted hydrogen, and 

 carbonic acid, which impregnate others within a certain distance 

 of this axis of elevation. 



