28 UPHEAVING OF u IGNEOUS HOCKS.” 
eluded that some upheaving force had caused these 
disturbances in oui’ rocks. 
The new theory respecting granite, &c. I may 
observe, if a correct one, serves to explain the con¬ 
trariety of circumstances, under which that rock 
makes its appearance,—sometimes near, or connect¬ 
ed to fossiliferous slate,—sometimes in connection 
with non-fossiliferous slate, or other rocks of that 
order. It may explain, why on Morweldown (and 
perhaps in other spots also) a lode of copper, passes 
from schist to granite in an uninterrupted manner.* 
It may perhaps originate a reasonable inference, that 
during the elevation of this mass, it had dislocated 
certain upper beds of slate, &c. and altered, or re¬ 
versed their dip. During a visit to the Eddystone, 
(gneiss, with granite near it) I was astonished to 
observe that a bed of slate at the nearest point of 
land in Cornwall, (Penlee Point) had a vertical po¬ 
sition, and even partly dipped northwardly, contrary 
to every other instance I had witnessed. At the 
Start it dips northerly. Near Turnchapel it dips 
northeast, and at Mount Batten the limestone is 
nearly vertical, the whole country in that direction 
south of Plymouth, seeming to have been dislocated 
by an upheaving force. At Deadman’s Bay, the lime 
is nearly horizontal in one spot. 
Some varieties of our trapp bear singular resem¬ 
blance to substances which have been submitted to 
the action of fierce fire, being cellular, spongy, and 
variously coloured; one sort, is prone to turn out in 
oblong, rounded, scaly nodules, and it is worthy of 
note, (because possibly the two facts are similarly 
derived) that greenstone likewise assumes at some 
spots, large reniform, or ovoid forms, and being 
sometimes superficial, these blocks are seen to have 
escaped (whether by mere gravity, or during the 
* See Risdon’s Survey of Devon, Preface. 
