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HUTTONIAN THEORY. 



287 



confiderable body of calcareous flrata. 



Som 



e 



of thefe fpecimens were brought to Edinburgh 

 about a year ago, and were fuppofed, I believe, 

 to contain an irrefragable proof of the Neptu- 

 nian origin of the bafaltic promontory where 

 they were found. 1 went to fee thefe fpecimens 

 in company with Lord Webb Seymour and Sir 

 James Hall ; and, on examining them carefully, 

 we were all of opinion, that the ftones which 

 contained the (hells, or the impreffions of the 



Ihells, were no part of the real bafaltes. 



They 



were all very compact, and had all more or lefs of 



a liliceous appe 



fuch 



as 



f ch 



aiinotil they had nothing of a fparry or cryftallized ft 



their fract 



hoidal 



d but 



fligbtly 



1 



In two of them, one of which 



bore the impreffion of a comu ammonis, the fchif 

 tofe texture might be diftindly perceived. A fpe- 



cimen 



hieh 



panied th 



but in which 



there was no (hell, ferved very exactly to expl 



the relation b 



bafalte 



Part of 



th( 



ft 



d th 



fait, and the reft a fort of hornft 



fam 



e 



th th 



m 



was a true ba- 



me, exactly the 

 hich the iliells were, and 



unlike t.-e jafper that is under the whinft 



of Sal- (bury Crag, and in contad with it : fo 



that on th 



h 



It 



dent, that the rock 



containing the ihells is the fchiftus or ftrati- 

 lied ftone^ which ferves as the bafe of the ba-. 



^ inuf 



1 



