326 SIR JAMES HALL on the Consolidation of the Strata. 



occurs, in which a bottom of great depth is surrounded by a 

 ridge comparatively shallow, we may expect to find the lower 

 portion, at least, of the water in a state approaching to brine. 



Without any such theoretical explanation of the manner in 

 which a supply of salt is supposed to be formed, it may perhaps 

 be considered sufficient for my purpose, to recal to the recollec- 

 tion of the Society, that there are in almost every part of the 

 world vast districts of rock-salt, and in some countries extensive 

 salt lakes and salt rivers ; and in our own country we have 

 many instances of brine springs, besides rock-salt in abundance. 

 Here then it seems to me, we are plentifully furnished with 

 the means of accounting, in the manner experimentally shewn, 

 for the agglutinations of such gravel as that of Aikengaw and 

 for the strata of the Salt-Heugh, which, by an easy analogy, 

 may be transferred to sandstone in general, and, perhaps, to 

 stratified rocks of every description. 



A member of this Society, however, well known by his scien- 

 tific acuteness, alleged, first in his public lectures, and afterwards, 

 upon my requesting an explanation of his objection, again re- 

 peated, that I was not justified in such theoretical conclusions, 

 respecting the influence of heat at the bottom of the sea, since 

 the neighbourhood of the cool water would necessarily counter- 

 act that influence. 



In answer to this difficulty, I must beg leave to remark, that, 

 in all my experiments above alluded to, the sand (viewed by means 

 of the gun-barrel) was seen to become red-hot during the process 

 of consolidation, while the superincumbent brine remained boil- 

 ing above ; and it was even found easy, by supplying cool brine 

 in sufficient quantity, to maintain the temperature of the fluid 

 permanently such, that the hand could be plunged into it at 

 top, without injury, the sandstone below remaining all the while 

 at a full red heat. But whenever I repeated this experiment* 



