| Presidential Address—The Geology of Devon. 518 
chlorite rocks are the metamorphic equivalents of interbedded sheets 
of igneous rock on the north side of the syncline, though ingenious, 
is scarcely convincing. A series of chemical analyses at this stage 
of the argument would be useful. On striking the balance of 
evidence it seems probable that the slaty beds are wholly distinct 
from the true metamorphic rocks in the south. If reliance is to be 
placed on the microscope, this must be regarded as proved. I would 
remark also, that few things are more deceptive than an apparent 
sequence in a highly compressed region; so that the presence of 
a fault is more often a matter of inference than of direct observation 
in such districts. 
It is not absolutely necessary for us to believe that the crystalline 
schists of the Bolt are of Archean age, if indeed we know exactly 
what is meant by Archean. But I think that there are fair reasons 
for considering them to be older than the Devonian against which 
they abut ; and that, in point of fact, they owe their present position 
to having been involved in the anticlinal uplift of which there are 
traces here and there along the channel shores of the Devon-Cornwall 
peninsula. 
And this brings me to the consideration of the general structure 
of Devonshire from a stratigraphical point of view. Regarded as 
a whole, every one knows that Devonshire is a broad synclinal. 
The Lower Devonian beds of Torquay on the one side and of Linton 
on the other are practically on the same horizon, and, omitting minor 
curves and breaks, the extensive region between these two points 
is one great trough of Paleozoic rocks. But if we start again from 
the neighbourhood of Torquay in the direction of Dartmoor, it is 
still found that, on the whole, newer beds come to the surface as 
the south-east flank of the granite mass is approached. No matter 
how the beds in the immediate vicinity of the granite may be 
affected, the south-east flank of Dartmoor must be regarded as lying 
in a depression, relative to the coast rocks at the points already 
mentioned. Again, shifting our position considerably with regard 
to the central mass of granite, we find a suspicion of Lower Devonian 
rocks at Yealmpton, and a certainty of them at Looe, all pointing to 
the conclusion that there are traces of the northern wing of an 
anticlinal on the Channel coast. An inner and more deeply-seated 
portion of this anticlinal, in places resulting in a dislocation and 
possibly an inversion, has brought up the erystalline schists of the 
Bolt. With these perhaps may be associated inferentially the 
gneissic rocks in the neighbourhood of the Eddystone, mixed with 
other crystalline rocks, such as those mentioned by Mr. Arthur Hunt. 
But if the submarine granite or granites have had no more effect than 
that of Dartmoor in uplifting the country, they must be regarded as 
factors of minor importance in the structure of the Channel anticlinal. 
Of course, the probability of an anticlinal axis in the English 
Channel has long been recognized, and indeed the space between 
the Devon-Cornwall peninsula and Brittany is wide enough for 
many a flexure, the mean result being an east-and-west axis of 
principal uplift, the exact position of which it is impossible to 
DECADE III.—VOL. VI.—NO. XI. 33 
