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2 PEOF. T. G. BONNET ON THE GEOLOGY
this district is described in the paper of Sedgwick and Murchison
'^ On the Stratified Deposits of Devonshire " (Trans. Geol. Soc.
ser. ii. vol. v. p. 633), and in the " Eeport" of Sir H. Dela Beche.
In these two works, which after the lapse of more than forty years
are still of the greatest value, the stratigraphy of Sonth Devon is
excellently sketched, and the main problems relating to it are
clearly enunciated. Briefly stated, the latter amount to this : Does
this district indicate a progressive metamorphic action, which in-
creases in intensity as we proceed southwards ? or do we find here
two distinct and independent series, the southern, a group of highly
metamorphosed rocks, true schists, the northern, slates, such as are
common elsewhere in Devonshire, with no signs of a transition
from the one to the other? Sedgwick and Murchison, if I under-
stand them rightly, incline to the latter view ; Sir Henry De la
Beche inclines, though hesitatingly, to the former, which appears
generally to have found favour with later writers, including Mr.
Pengelly himself*. Accordingly the schists of the southern part of
this district are regarded simply as altered Palaeozoic rocks, possibly
of Devonian age, whose upheaval is connected with the series of
Pig. 1. — Shetcli-majp of the South Devon Coast from Torcross to
Ho;pe Cove. (Scale about 3 miles to 1 inch.)
a. Slaty Series.
b. Mica-schist.
c. Chloritic schist.
A A. Bands of Mica-schist interstratified with
lower parts of Chloritic schist.
a a. Boundary in the Survey Map.
B. Axis of Chloritic schist.
poet-Carboniferous disturbances which have affected the south-west
of England, and whose metamorphism is probably due to some
proximate protrusions of igneous rock, analogous to those yet visible

• This opinion is also adopted, with some hesitation, by Dr. H. B. Holl, in
  

his invaluable paper " On the Older Rocks of S. Devon and Cornwall," Quart.