Remarks-on the Transition. Rocks of Werner. 95 
doned. I find, however, in a recent publication, something 
similar to it maintained by De Luc, who asserts that the 
veius at St. Michael’s Mount are not granite, but merely 
quartz, which traverses the granite as_well as the stratified 
rock. I cannot comprehend how De Luc could have been 
so much deceived at this place; as simple inspection of the 
smallest specimen will prove that be was mistaken. 
It was next said, that the veins In question were not true 
veins, but such as are termed Cotemporaneous. To sup- 
port which, it was boldly asserted, that they never extended 
beyond the limits of such rocks as were composed of the 
same materials, gneiss and mica-slate. 
I trust it is now distinctly shown, that they do extend 
beyond these limits, and likewise that they traverse rocks 
from which by no method of reasoning it can be supposed 
that they could possibly be formed by secretion. 
The last opinion is that which has recently been brought 
forward by Dr. Berger*. After describing the granite 
veins of St. Michael’s Mount, he proceeds to say, that they 
are simply elevations on the plane of the gramte existing 
previous to its being covered by the stratified rock ; that 
the spaces between them were filled up as the grauwacke 
was deposited; and hence the abrasion of the surface 
brought to light a section which has merely an appearance 
of veins, 
Were the devotion of Dr. Berger to his master less con- 
spicuous in his geological disquisitions, I should be in- 
clined, on the above statement, to call his character as am 
observer in question, having passed over in silence the de» 
tached masses of killas, which he could not fail to observe 
included in the granite, and which the above hypothesis is 
as far from accounting for as either of those mentioned 
before. 
I have only a few specimens (Nos. 39, 40, 41.) to lay 
before the Society from the veins of St. Michael’s Mount ; 
but they are equally interesting and satisfactory. One 
exhibits a portion of the killas bounded on each side by 
granite; another, a portion of two granite veins travers- 
ing killas; and the third, a mass of killas included in the 
granite, 
Simple inspection is sufficient, in the first place, to show 
that the opinion of De Luc is. groundless with respect to 
the substance of these veins. 6ne of the specimens also 
contains two small veins of quartz, which are of the kind 
called Cotemporaneous; these keep the direction of the 
* Transactions of the Geological Society, vol. i, p, 147. 
seams 
