52 SKETCH OF THE 



I was at one time persuaded that the above rocks were of analogous 

 formation with the iron sand of the English Geologists — though in their 

 structure, and in many of their characters, they do not resemble the rocks 

 of this formation, still these characters might have been modified by 

 many and various causes. Their position gives some color to such a 

 supposition, and a breccia, somewhat similar to the one described, is 

 mentioned as associated with the iron sand. On this point, however, 

 I prefer saying nothing more. I am anxious to give as impartial an 

 account of the rocks as they occur, as I possibly can ; and it is difficult, 

 when once we have adopted an opinion, to void trying to trace analogies 

 which exist more in our own imaginations than in reality — not that I 

 believe that any individual would willingly deceive in matters of this 

 kind, but the fact is we are deceived ourselves. It is thus that science 

 degenerates into a system of vague hypothesis. 



The plains of this portion of the country are strewed with numerous 

 rolled masses of the above rock, and from the isolated position which it 

 occupies, viz. only on the summits of the hills, we may conclude that it 

 has been much affected hy those great denuding causes which have operated 

 with such amazing force over the whole surface of the globe. How far 

 this formation extends into Hardoti I know not^ — ^Captain Danger- 

 field in his map, lays down this district as a formation of ''hornstone 

 and porphyry." — But whether this hornstone be the same rock as the 

 quartzose breccia or not, I have had no opportunity of ascertaining. 

 As I before stated, he has applied the name to two rocks of very distinct 

 series. Large blocks of this quartzose breccia are constantly observed 

 at the base of the hills arranged in large globular heaps. These are 

 detached from the crags generally during the rains. The reason of this 

 is obvious. The water having penetrated into the rents and fissures of 

 the rock, is exposed to the heat of a nearly vertical sun, which usually 

 bursts out after the first fall of rain — the expansion thereby occasioned 



