File:The Quarterly journal of the Geological Society of London (12960514144).jpg

TOLCANIC EOCKS OF DAETMOOK.
289
Fig. 1. — Flan of the Brent-Tor Basin, showing the Faults and the
lines of the folloiuing Sections.
W. E.
are thrown into long anticlinal and synclinal folds. On the west a
small and nearly triangular area includes all that remains of the
Brent-Tor volcanic series in this direction. To the south it is
possible, as suggested in this paper, that the schistose beds about
Saltash, ten or twelve miles distant, may belong to this volcanic
series.
The first section which I have taken to illustrate the relations of
the beds is one running IST.jN'.W. across Eam's Down (fig. 2). It
Fig. 2. — Section (1) across Hani's Doivn.
N.N.W. S.S.E.
Milton
Eam's Down. Abbot. Combe. Twowell.
lies on the west of our typical basin. Here two beds of the volcanic
series are seen, the older marked with the letter c, the younger with
d. As they undulate, and their crests have been denuded, there are
three separate exposures of the bed c, flanked on either side by the
bed d. In speaking of these exposures as beds, it should be under-
stood that they commonly consist of a series of beds (lavas, tnffs, &c.).
The next section (fig. 3) runs in a S.S.E. direction, from Littonary
Down, across IIeathfield,to Tavistock. From Meather to Churlhanger
we see a synclinal disposition of the beds, which dip northwards to-
wards Lower Chillaton and Quether, while on the south the bed c
is repeated by several undulations, and is then succeeded south of
Tavistock by what I believe to be two older lava-flows, lettered re-
spectively a and h. These four series of beds a, 6, c, and d represent,
so far as I can ascertain, the whole of the Brent-Tor volcanic series
subjacent to the stack of lavas and agglomerates which constitute