320 SIR JAMES HALL on the Consolidation of the Strata. 



above described, of perfectly loose materials, traversed vertically 

 by a dyke, which, in its middle, consisted of whinstone, and was 

 flanked by solid conglomerate ; but this solidity abated gradually 

 till the conglutination of the rounded masses diminishing by de- 

 grees, the state of loose shingle and gravel was entirely restored 

 on both sides. The agglutinated mass adjacent to the dyke bore 

 no resemblance to the result of calcareous petrifaction ; scarcely 

 ever gave effervescence with acid ; and, by its gradual termina- 

 tion, differed from any whinstone-dyke I have seen to penetrate 

 the strata ; for, in the ordinary case, the termination of the cry- 

 stallite against the adjoining aggregate through which it passes, 

 is almost always quite abrupt. 



About a hundred yards higher up the valley of Aikengaw, 

 there occurs an agglutination similar to the last, though without 

 any whin-dyke, and sufficiently strong to resist the elements, by 

 which the surrounding matters had been washed away, leaving 

 the pudding-stone, or agglutinated shingle, to stand up by itself, 

 in a manner remarkable enough to have attracted the notice of 

 the peasantry as something supernatural, since they have bestow- 

 ed upon it the name of the Fairy's Castle. 



Farther up the stream, other agglutinations occur frequent- 

 ly, as we could see in little narrow glens cutting through the 

 mass ; and higher still, they are so numerous as to meet and con- 

 vert the whole into one unbroken mass of pudding-stone, occu- 

 pying all that is exposed to view. 



These very remarkable, and, to me at least, novel appearances, 

 were the first which suggested the idea, that the consolidation 

 not only of this class of conglomerates, but of sandstone in ge- 

 neral, had been occasioned by the influence of some substance in 

 a gaseous or aeriform state, driven by heat into the interstices 

 between the loose particles of sand and gravel, where it had 

 acted as a flux on the contiguous parts. On considering what 

 this penetrating substance might be, and from whence it could 



