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Art. XXVII.— 1 . Secondary Greenstone and Wacke not of 
Volcanic Origin. — % Veins which connect Mineral Beds to^ 
gether^ not confined to Trap-rocks. — B. Trap Veins (Whin^ 
dikes ) probably of cotemporaneous Formation with the trap^ 
rocks which they traverse. By Professor Jameson. Com* 
municated by the Author. 
I. — Secondary Greenstone and Wacke not volcanic. 
V OLCANISTS maintain, that greenstone ( whinstone ) is a 
subterranean lava, which has been projected, in a state of igne- 
ous fusion, from the interior of the earth, amongst previously ex* 
isting strata ; while the Neptunists are of opinion, that greenstone 
and all other trap-rocks have been formed at the same time, and 
in the same manner, as the strata with which they are associated. 
Hence, according to the one hypothesis, all rocks found in con- 
tact with greenstone are more or less altered by the heat which 
must have flowed from it w’hilst in a state of fusion, so that 
sandstone becomes highly indurated and clay is converted into 
jasper ; but, on the other view, the greenstones are said to ex- 
hibit precisely tlie same general relations as are observable in 
sandstone, slate-clay, and other similar rocks, which are sup- 
posed by the Plutonists to have been formed by deposition 
from water, 
Lothian Street Quarry^ Edinburgh, ' 
It frequently happens, that we have opportunities in this 
neighbourhood of trying the truth of these opinions by an 
appeal to facts. Very lately in an extensive quarry open- 
ed in Lothian Street, in the course of the building operations on 
the south-east side of that street, a fine section was made of the 
rocks of the coal field, in wLich the appearances proved the fal- 
lacy of the volcanic hypothesis of the formation of secondary 
greenstone, but were favourable to the opinion of the Neptu- 
nists. We shall now give such a description of this quarry, as 
will enable our readers, not only to form a distinct conception 
of the various alternations and relations of the strata wLich were 
cut through, but also to judge how the -facts bear on the two 
