232 Prof. B. Silliman junior on the 



Here we have the dry beds of subterranean rivers, exactly as they 

 were left thousands of years ago by the stream which flowed through 

 them when Niagara was young. No angle is less sharp, no groove 

 or excavation less perfect than it was originally left, when the waters 

 were suddenly drained off by cutting their way to some lower level. 

 The very sand and rounded pebbles which pave the galleries now, 

 and formed the bed of the stream of old, have remained in many of 

 the more distant galleries untrodden even by the foot of man. The 

 rush of ideas was strange and overpowering as I stood in one of 

 these before unvisited avenues, in which the glow of a lamp had 

 never before shone, and considered the complex chain of phenomena 

 which were before me. There were the delicate silicious forms of 

 cyathophylla and encrinites, protruding from the softer limestone 

 which had yielded to the dissolving power of the water ; these carried 

 me back to that vast and desolate ocean in which they flourished, 

 and were entombed, as the crystalline matrix was slowly cast around 

 them, mute chroniclers of a distant epoch. Then were the long 

 succeeding epochs of the upper secondary ; and these past, the slow 

 but resistless force of the contracting sphere, elevated and drained 

 the rocky beds of the ancient ocean : the action of meteorological 

 causes commenced, and the dissolving power of fresh water, fol- 

 lowing the almost invisible lines of structure in the rocks, began 

 to hollow out these winding paths, slowly and yet surely. But I 

 need not attempt to paint a picture in detail whose outlines in 

 simple truth are so grand, and 1 must apologize for detaining you 

 so long. I wish that all my scientific friends could visit the Mam- 

 moth Cave ; it teaches many lessons in a manner not to be learned so 

 well elsewhere, and in this respect I was most agreeably disappointed. 

 1 had heard that its interest was chiefly scenic ; but I found it to ex- 

 ceed my utmost expectations, as well in its illustrations of geological 

 truth, as in the wonderful character of its features. I will not de- 

 tain you with any attempts at descriptions of single parts, as no 

 description can awaken those peculiar and deep emotions which a 

 personal study of its details is calculated to produce. 



I know not how or where to stop, however, in my account of this 

 interesting place. Excuse me if I trespass yet a little longer on 

 your patience. In traversing the high vaulted galleries of the cave, 

 our attention was occasionally arrested by the sound of falling water. 

 We soon learned that, in such cases, we were in the vicinity of an 

 entirely new feature in this subterranean region. Approaching 

 cautiously to the spot from which the sound proceeds, we find usually 

 a deep pit, often surmounted by a dome. These pits are of various 

 depths, but usually not less than 100 feet, and cut down with walls 

 of limestone so entirely vertical, that in many cases we were able to 

 measure them from the edge with a line and plummet. When the gal- 

 lery leads to the upper portion of one of these vertical excavations, it 

 is called a pit ; if, on the other hand, the approach is from beneath, it 



