64 DEPOSIT OF THE GRAUWACKE ROCKS. 
ingly a mere continuation or portion of the same,— 
and this arrangement made too in defiance of mani- 
fest and great obstacles. 
When we take a general and connected survey 
of the facts presented by the geology of this district 
with the view to frame a systematic notion of the 
respective ages of our rocks, and of their mode of 
deposition, the mind is inevitably perplexed by 
contending problems suggested by the want of uni- 
formity in the phenomena they exhibit. To select 
that theory most congenial to our apprehensions 
and judgments, we must draw that picture the parts 
of which are the most consistent together, and the 
most in unison with the results attained by exami- 
nation of the phenomena of other localities ; and if 
the statements of this sketch shall be found capable 
of supporting, or at least not in contradiction to 
the popular views of the general geology of the 
globe, no useless opposition, or multiplication of 
theories will be committed. 
We are first to remember, that the principal basis 
of the whole fabric is in all probability granite ; it 
is elevated by igneous agency into hills of vast size 
in the region of Dartmoor, and sweeping as I con- 
ceive southwardly passes to a submarine position, 
appearing however in the channel as the Eddystone 
and at the Bolt Head. Besides the granite, our 
gneiss, and the porphyritic and serpentinous for- 
mations and some other rocks belong to the same 
series. We are to consider, that the mountainous 
nature of the granite is in all probability preserved 
throughout its whole extent, and that this chraac- 
ter would in some degree at least, influence the 
appearance as regards elevation, of the strata re- 
posing onit. Reflecting on the number and variety 
