474 ON THE NEWEST FLOETZ-TRAP 



GREENSTONE. 



Two veins of this rock intersect the sandstone 

 strata between North Berwick and Tantallon 

 Castle. One of these veins is small-granular, com- 

 pact, and porphyritic, and twelve or fourteen feet 

 wide ; the other is also small-granular, contains a 

 mixture of sand, and is only a few feet in width. 

 Both of these veins pursue a north-easterly direc- 

 tion, and are nearly vertical ; they have numerous 

 veins of calc-spar traversing them. 



It cannot be easily said, whether these veins are 

 derived from beds of greenstone belonging to the 

 coal-formation, or from the newest deposite of the 

 overlying trap. I am at present more inclined to 

 the former supposition, on account of having ob- 

 served beds of greenstone at Gullon, to the west- 

 ward, conformable with coal strata, and not ha- 

 ving yet observed any distinct greenstone in the 

 newest flcetz-trap. 



JASPERS. 



Numerous veins of this substance occur at the 

 Garlton Hills, Pencraik, near Traprain, and other 

 places j it approaches more nearly in characters, 



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