VICINITY of EDINBURGH. ATS 
abruptly at each end by the greenftone; in another, that fub- 
ftance finks fuddenly as it weré into a gap in the ftrata, and be- 
ing loft in rubbifh, has fomewhat the appearance of a dike. 
Beyond this a double horizontal wedge of greenftone, with the 
ends turned downwards, appears among the ftrata; and a little 
farther, towards the north, a roundish mafs of the fame fubftance 
alfo occurs ; this has very much the appearance of an included 
fragment, but the decompofition of the fandftone has juft be- 
gun to expofe its connection with the rock above. 
On the fandftone, Porphyritic Greenftone (No. 3.) refts. The 
colour of this is reddifh-brown; the texture is fine-grained ; 
and it contains finall {pecks of flefh-coloured calcareous fpar. 
It is traverfed in various places by veins of Hematitic Iron-ore 
(No. 4.) accompanied with fulphate of barytes.. Thefe two 
_ fpecimens have very much the charater of fome varieties of 
porphyry-flate, and on breaking one mafs, I obferved a tenden- 
cy to a flaty arrangement. In different places of this quar- 
ry, the greenftone aflumes a variety of appearances (No. 5. 
and 6.), fome of which might be attributed to decompofition. 
I do not conceive, however, that any external caufe has ever 
had much effect upon this rock, although in fome places it has 
entirely loft its luftre, (No. 7.), and might be miftaken for © 
trap-tuff, were it not for the fhape of the cryftals. 
Asove this, the rock graduates into a highly oryfal- 
line Porphyritic ftone, (No. 8.) the pafte of which is of a 
brownifh-grey colour, very clofe-grained, with an uneven 
fplintery fracture, containing both cryftals of felfpar and horn- 
_ blende. 
In this quarry there are feveral inftances of slikensides, 
_ one of which is rather remarkable, it occurs in’an inclined rent 
in the fandftone: the traces of the flip, (No. 9.), are horizon- 
; tal, 
