1814.] on Transition Rocks. 289 



for the granite of Cornwall contains fragments ; and this, as has 

 been shown, is according to Werner, distinctive of the newest 

 granite. We are, in consequence of all this, destitute of any proof 

 of the third proposition of Mr. Allan, namely, that " the granite 

 which forms the nucleus round which all the other rocks were de- 

 posited," {tliat is the first granite Jormalion) "is actually of a later 

 date than the transition series." 



Mr. Allan in his former paper asserted, that " floetz rocks are 

 never found conformable with the transition rocks." He was called 

 upon by me for his proof of this, p. 106 of your August NTumber. 

 But he'has thought proper to decline making any reply. He still 

 withholds his proof. 



I likewise objected to a statement of his respecting granite veins; 

 which he says, according to the Wernerian geognosy, occur only 

 in such rock? a* are composed of the same constituents, such as 

 gneiss and mica-slate ; and I mentioned that I had never, for my 

 part at least, seen or heard of any writer on Werner's system who 

 made such an assertion. On the contrary, Professor Jameson, in 

 his third volume p. 107, states that granite veins traverse, not 

 only gneiss and mica-slate, hut clay-slate : a rock not comj)osed of 

 the same coastituents with granite, and every body knows that 

 mica-slate itself wants one of them. Mr. Allan in his answer 

 takes no notice of this matter. 1 wished for his reason, but he has 

 produced none. Perhaps he is like a celebrated character in the 

 play, unwilling, though he may have plenty of reasons, to give 

 me one on compulsion. 



I now leave you and your readers to judge whether I was not 

 justifiable in imputing to this gentleman inaccuracies or mis-state- 

 ments. But I find that I am not the only person who has had 

 reason to complain of him in this respect. I observe in the Phi- 

 losophical iVIagazine for December last, p. 429, a paper by J. A. 

 De Luc, tsq. F.R.S,, entitled, On the Phenomena of St. Michael's 

 Mount in Cornwall, in which he is at great pains to shew that 

 Mr. Allan, in his Remarks on the Transition Rocks of Werner, 

 has given a very erroneous account of his oljservations. De Luc 

 say-j that Mr. Allan must never have seen his book at all ; but 

 must have contented himself with an account of it by some inat- 

 tentive rcvievver. « If," says De Luc, " Mr. Allan had seen ray 

 own work, he would not have thought I was mistaken; since I 

 have not only described, myself, the very phenomena that he opposes 

 to me, as observed in the specimen which he laid before the 

 Edinburgh Society, but this is only a very small part of the geo- 

 logical circumstances which 1 have described in that country The 

 principal of them against the Huttonian sy^tem were : the stratifi- 

 cation of granite, the broken and shattered state of its strata, no 

 less than tho^e of killas by the same cause ; that of the subsidence 

 of part of them ; and the evidence of the veins of St. Michael'* 

 j Mount having all the characters of mineral veins, on wliich the 



Huttonian system had spread so many errors." 

 iN° IV. Vol. IH. T 



