VICINlTr of EDINBURGH. 429 



ferving, that all the indurated fandftones of this country, con- 

 tained more or lefs calcareous matter, while the unindurated 

 fpecimens from Ireland, did not afford the flighteft indication 

 of that fubftance, when fubjected to the fame teft. 



Before I take leave of Salifbury Craig - , I muft notice one 

 more circumftance, which, fo far as I have hitherto feen, is 

 quite peculiar to the fpot. I mean the occurrence, in veins, of 

 a fubftance in all refpecls fimilar to the indurated fandftones, 

 I have juft been defcribing. The firft of thefe I obferved, is 

 about thirty paces north of the vein. The ground being cut 

 away, in order to fee its connection with the ftrata, it branched 

 out like the prongs of a fork, and had the interftice filled with 

 a red decompofed fubftance (No. 69.), fimilar to that which 

 occurred at the extremity of the included ftripe of greenftone 

 in the vein. Where the prongs join, it is about three or 

 four. inches wide, and is there, partly compo fed of indurated 

 fandftone, and partly of hematitic iron-ore and calcareous fpar. 

 (No. 70.) Higher up, where the vein is narrower, it is whol- 

 ly compofed of fandftone, the fpecimen, No. 71., being the en- 

 tire thicknefs of it. - Here the grain is finer than at firft, and, 

 higher up, it becomes ftill more fo, (No. 72.) It ftill conti- 

 nues to taper upwards, and even when reduced to lefs than half 

 an inch, the fubftance retains the ufual afpect of indurated fand- 

 ftone, (No. 73.) This vein rifes about twenty to thirty feet 

 into the rock, always diminifhing, and about that height dif- 

 appears. I have remarked other veins, alfo containing fub- 

 ftances fimilar to indurated fandftone (No, 74.), one was of 

 a much larger fize than that above defcribed (No. 75.), but the 

 grain not near fo compact, (No. 76.) 



These veins all fet off from the lower furface, and fo long 

 as they are of any confiderable thicknefs, the including rock is 



ftained 



