REV. J. C. ATKINSON ON THE MINERALS OF BERWICKSHIRE. 137 



what is this ] Calcareous spar 1 Too heavy for that surely. 

 Ah ! I see, it is calc-spar, in a setting of heavy-spar or sulphate of 

 baryta. Here, again, we liave a curious combination. Outside is 

 crystallized sulphate of lime or selenite ; on the other side calc-spar ; 

 a vein of blue calcedony passing into quartz ; next to it quartz, 

 much impregnated with iron ; and then more calc-spar. See here, 

 too, what a quantity of carbonate of iron ! in two forms, crys- 

 tallized and massive, the latter with a considerable per cent, of 

 silica. And observe how it effloresces where exposed to the at- 

 mosphere and damp. Some is quite reduced to powder, varying 

 in colour fi-om yellow to dark brown, and consisting almost en- 

 tirely of oxide of iron.* In that bank opposite us, you see a 

 quantity of heavy- spar. You might almost get a bushel of it. 

 It is in small fragments or crystals, of, for the most part, modi- 

 fied forms of the rhomboid. Much of it has a siliceous oxide of 

 iron adhering to it, and evidently deposited originally on some 

 other crystallized mass, — probably, by the form of its crystals, 

 fluor-spar. The siliceous oxide, when broken, exhibits, as you ob- 

 serve, cavities which contain the simple oxide in powder. A little 

 to thft right, again, we have more of the barytes, somewhat radiant 

 in its formation, and beautifully white. It adheres to something 

 solid, in which respect it is unlike that we have just inspected. 

 And what is this something 1 A light blue mineral, in combina- 

 tion with a dark substance, with straight and weathered surface, 

 the dark colour of which does not penetrate far. This is calc- 

 spar ; but what is the blue substance? Its fracture is that of ser- 

 pentine, and its comportment before the blowpipe not dissimilar. 

 But I never heard of blue serpentine, and Mr Tennant thinks it 

 consists chiefly of carbonate of lime. This portion looks not un- 

 like blue heavy-spar ; and thb curd-resembling matter, overlying 

 some of the calc-spar, — what may it be 1 A combination of lime 

 and baryta I take it. Pass on a little. It is difficult walking ; 

 but we shall not need to descend if we take care. Here, we come 

 to a coarse easily- fissile rock, with numerous concretions of quartz, 

 both crystallized and uncrystallized. Here is a drusy cavity, 

 lined with pyramidal quartz crystals, most of them shewing but four 



* This change of the carbonate into the oxide of iron may be well seen in 

 many places along the coast of Eyemouth and Coldingham. The yellovrish 

 carbonate is quite brown where exposed to the atmosphere, and friable on its 

 surface. 



