VIC IN IT T of EDINBURGH. 417 



fragment of the ftratified matter imbedded in the green- 

 ftone, a circumftance eonne&ed with a very important clafs 

 of facts. 



No. 16. This fpecimen of greenftone is remarkable, as exhi- 

 biting a variety of colours j thefe are not blended, but diftinct- 

 iy divided from each other. The colours are iron-grey, light- 

 grey, dark-red, and brick-red. 



No. 17. This fpecimen is a ftrong example of the improprie^ 

 ty of the name which it bears ; it is a greenftone, decidedly of 

 a red colour. The fingular penetration of ferruginous matter, 

 which is exhibited in various parts of this rock, is not eafily ac- 

 counted for 5 but fuppofing it to have been once in a flate of fu- 

 sion, it may have obtained this fuperabundance of iron by ab- 

 forption, as the adjoining ftrata frequently abound in that 

 mineral. 



In various parts of the Craig, veins of a peculiar nature may 

 be obferved ; they are compofed precifely of the fame ingre- 

 dients as the rock, and are diftinguifhable only by the red co- 

 lour of the felfpar, (No. 18). Thefe are termed contemporaneous 

 veins, or veins of secretion s they are deeply waved, and gene- 

 rally follow the direction of the bed. Some of them prefent a 

 very bright brick-red colour, (No. 19.), mixed with fpecks of 

 calcareous fpar. 



Nos. 20, 21. in thefe fpecimens, are fmall globules of a black 

 earthy fubftance, which I am at a lofs to name. I mould have 

 conlidered it Amphibole, but for the next fpecimen, (No. 22.), 

 in which the fame fubftance appears to occur in irregular 

 fragments. 



No. 33. Analcime with cryftallifed Calcareous Spar. I be- 

 fore noticed, that it was in the heart of the bed where the 

 fubftance of the greenftone prefented the cryftalline texture in 



Vol. VI. P. II. 3G the 



