it of Budleigh Salterton, whence they are
traceable inland towards Rockbeare. These are succeeded by the Keuper
marls and sandstones, well exposed at Sidmouth, where the upper
Greensand plateau is clearly seen to overlie them. The Greensand
covers all the high ground northward from Sidmouth as far as the
Blackdown Hills. At Beer Head and Axmouth the Chalk is seen, and at
the latter place is a famous landslip on the coast, caused by the
springs which issue from the Greensand below the Chalk. The Lower
Chalk at Beer has been mined for building stone and was formerly in
considerable demand. At the extreme east of the county, Rhaetic and
Lias beds make their appearance, the former with a "bone" bed bearing
the remains of saurians and fish.

Dartmoor is a mass of granite that was intruded into the Culm and
Devonian strata in post-Carboniferous times and subsequently exposed
by denudation. Evidences of Devonian volcanic activity are abundant in
the masses of diabase, dolerite, &c., at Bradford and Trusham, south
of Exeter, around Plymouth and at Ashprington. Perhaps the most
interesting is the Carboniferous volcano of Brent Tor near Tavistock.
An Eocene deposit, the product of the denudation of the Dartmoor
Hills, lies in a small basin at Bovey Tracey (see BOVEY BEDS); it
yields beds of lignite and valuable clays.

Raised beaches occur at Hope's Nose and the Thatcher Stone near
Torquay and at other points, and a submerged forest lies in the bay
south of the same place. The caves and fissures in the Devonian
limestone at Kent's Hole near Torquay, Brixham and Oreston are famous
for the remains of extinct mammals; bones of the elephant, rhinoceros,
bear and hyaena have been found as well as flint implements of early
man.

_Minerals._--Silver-lead was formerly worked at Combe Martin near the
north coast, and elsewhere. Tin has been worked on Dartmoor (in stream
works) from an unknown period. Copper was not much worked before the
end of the 18th century. Tin occurs in the granite of Dartmoor, and
along its borders, but rather where the Devonian than where the
Carboniferous rocks border the granite. It is found most plentifully
in the district which surrounds Tavistock, which, for tin and other
ores, is in effect the great mining district of the county. Here,
about 4 m. from Tavistock, are the Devon Great Consols mines, which
from 1843 to 1871 were among t