54 



A number of shells of the common species, Helix Jallax^ 

 or one closely resembling it, were also found, most of them 

 imbedded in the most solid part of the stalagmite, so that 

 the lip cannot be seen. 



Evidently, therefore, the relics are of almost recent date, 

 no trace of any extinct species having been found among 

 them. Several considerations may enable us to limit the 

 date more closely. 



In the first place the whole Cuyahoga gorge is post- 

 glacial in date and is excavated in a purely siliceous stratum, 

 the Carboniferous Conglomerate. Yet all the springs which 

 abound on the south side yield hard water, and many o^ 

 them have built up a mound of calcareous sinter at the 

 point of outflow. The lime is derived from the drift-clay 

 and gravel which overlies the Conglomerate. It follows, 

 therefore, that they could not have existed before the drift 

 was present. The pre-existing strata of the coal measures 

 were like the Conglomerate, non-calcareous. We are safe, 

 therefore, in inferring that the stalagmite is at most not older 

 than the earliest of the drift beds of the county. But the 

 crevice cannot be more ancient, or it would have been earlier 

 filled. 



Again, the lime-depositing springs cannot have existed 

 before the glen was excavated, and this being altogether 

 post-glacial determines the question in favor of the late date. 



Yet, again, the crevice is far up the glen, nearer to its 

 upper than its lower end. The excavation of the glen must 

 therefore have been far advanced when the stalagmite was 

 deposited. 



1, therefore, incline to the opinion that the crevice in ques- 

 tion was one of those developed in the Carboniferous Con- 

 glomerate by the slipping of the rock-mass alongside as the 

 excavation advanced. Many instances of this sliding can be 

 seen today where great blocks are slowly gliding forward 

 over the soft surface of the Cuyahoga shale. Into the 



