MIDiDLE DISTRICT OF SCOTLAND?. 6^1 



8. Clinkstone, This beautiful rock occurs^ in 

 Beds and veins, in the red sandstone. 



9. Compact Felspar. Compact felspar, gene- 

 rally of a red colour, and often passing into clay- 

 stone, occurs in beds in this red sandstone district. 



JO. Porphyry, This interesting and beauti- 

 ful rock occurs in considerable abundance in beds 

 and veins in the red sandstone and conglomerate. 

 Claystone, ironstone, and felspar-porphyries, are 

 those met with in this tract. There are some- 

 times amygdaloidal, and occasionally the crystals 

 of felspar, are wanting, when beds or veins of 

 claystone or felspar appear in place of the charac- 

 teristic porphyry. The claystone-porphyry ap- 

 pears to pass into claystone^ — this into sandstone^ 

 Sometimes the porphyry is conglomerated, and 

 then it sometimes contains imbedded balls of gra- 

 nite, and angular pieces of hornblende rock and 

 clay-slate. 



1 1 . Greenstone, This rock occurs in beds, im- 

 bedded masses, mountain masses, and veins, in th^ 

 red sandstone and conglomerate. 



12. Pitchstone, Green and black- coloured va- 

 rieties of this rock, are met with in the form of 

 imbedded masses, beds and veins, in red sand- 

 stone. 



s s 2 



