194: MINERALOGY OF THE PENTLAND HILLS. 



rV. Greenstone, 



This is not a frequent rock in the floetz series 

 of the Pentlands. It is in general small granular, 

 and appears to pass into basalt, and sometimes to 

 form that variety of rock named Basaltic Green- 

 stone. It is at times amygdaloidal, and then it 

 contains calcareous spar and agate. It occurs 

 above the conglomerate at the north-east corner 

 of Turnhouse Hill, and at the base of Black Hill, 

 about a quarter of a mile from Habbie's How.. 

 Many rolled masses of a large granular greenstone,- 

 along with basalt and amygdaloid, occur in the 

 bottom of the West March Burn, but I did not 

 find any of these rocks in situ any where in the 

 course of the rivulet. • 

 , This rock appears to be associated with the 

 clinkstone, and probably occurs in beds below, ot 

 m ito " 



V. Compact Felspar, 



The colour of this rock, is flesh-red, or brownish- 

 red ; sometimes greyish and yellowish- white, and 

 ash-grey and yellowish-grey. It is massive. The 

 lustre is glimmering, and the fracture minute foli- 

 ated, and splintery, and sometimes conchoidal, some- 

 times slaty. , It is semi-hard and brittle. Specific 

 gravity 2^4p7 ^. Some varieties of the felspar exhi- 



* Vid. Mackenzie on Compact Felspar. Memoirs of the ' 

 Wemeriaw Society/' vol. i, p. 617. 



