Transactions. 71 



respects from the ordinary boulder clay was exposed be- 

 neath 15 feet of the latter. 



In the first place it is distinctly and regularly stratified, 

 dipping at an angle of about 30° due east ; secondly, it is a 

 compact, solid rock, so firm and hard that in cutting through 

 it dynamite had to be used oftener than the pick or the 

 wedge. This character of itself is sufficient to stamp it as 

 an almost unique case. Jukes, indeed, mentions the occur- 

 rence of a solidified glacial deposit in tiie south of Ireland, 

 but in that case solidification had been produced by the solu- 

 tion and subseciuent precipitation of the carbonate of lime 

 forming tlie boulders. It is also not uncommon to find the 

 boulder clay round a chalybeate spring hardened by the de- 

 posits of iron in the interstices of the deposit. Neither of 

 these explanations ap^Dly, however, to the present case. 



In the third place the boulders, sand, and clay are not 

 mixed confusedly together, but lie in distinct layers forming 

 beds of shale, sandstone, and breccia. 



The contained fragments vary in weight up to 14 lbs. 

 Many of them do not belong to any known rock of the 

 district, while, again, fragments of local Permian and Carbon- 

 iferous rocks are conspicuous by their absence. They are 

 remarkably angular, frequently presenting as fine and sharp 

 an edge as if newly broken by a hammer, and many of them 

 are unpolished by erosion, and present no ti'ace of striation. 

 The beds of sandstone and shale are of insignificant thick- 

 ness. The exposed section is about 400 feet in length, the 

 beds dipping at an approximate angle of 30 deg., which 

 would make their real thickness 100 feet, after making an 

 allowance for one or two small faults, which bring the same 

 bed twice to the surface. The beds are traversed by slicken- 

 sided ioints running north and south. The out-crop is 

 extremely uneven, presenting evidence of having suffei'ed 

 a considerable amount of denudation previous to being 

 covered by the overlying boulder clay. 



These are a few of the main features of tliis glacial 

 deposit, and as most natural objects contain their own history 



