OF THE SOUTH DEVON COAST. 5 
again to the slaty type, while south of the valley the characteristics 
of a schist are seen on closer examination to be not only more 
distinctly marked, but also permanent. Thus in the very first 
craggy boss N. of the valley at Hall Sands, after a few yards of 
rock so much decomposed and cut up by quartz veins as to be 
incapable of giving testimony, we come to a true slate. This can 
be split up into thin quadrangular or polygonal plates, whose upper 
and under surfaces have a glimmering satiny lustre, crumbling, or 
rather cracking and splitting up, when manipulated, after the 
manner of the fine-grained less flinty slates; while in all the rocks 
south of the valley, beginning with the very first crag, the surfaces 
are more waved, and have amore silky mica-like lustre ; the thinner 
edges of fragments can be split up by the knife into rather trans- 
lucent wavy folia; in short the demeanour of the rock is in all re- 
spects that of a micaceous schist. 
Texamined the crags beneath the hamlet of Hall Sands, until a 
reef, which projected into the sea, compelled me to mount above 
them. The rock is fairly uniform in character, being commonly 
a dull greenish schist, often marvellously corrugated, with “eyes” of 
quartz and with innumerable quartz-veins, the latter often being best 
developed in the loops of the corrugations, and seemingly produced 
by mineral segregation from the darker bands. Sometimes, how- 
ever, these veins are on a large scale, and traverse irregularly the 
mass of the rock. They also are frequently crumpled and corru- 
gated to an extraordinary extent, the dip of the schist, if we may 
trust the alternation of the finer quartzose and micaceous lamine 
(2. ¢. the foliation planes) as indicative of bedding, is to N.N.W. 
and is high, being perhaps on the average from 66° to 70°; but 
the crumpling and zigzagging of the layers is such that it is 
most difficult to estimate the dip, though there is a fairly clear 
intimation of a general E.N.E. strike. Mlica-schists (often greatly 
crumpled and corrugated), varying from a dull greyish green to a 
leaden or brownish colour, are traversed by the path leading to the 
Start lighthouse and therock. About the buildings is a mica-schist, 
which reminded me of those which so commonly occur on the flanks 
of the higher ranges in the Alps. Everywhere the schist, in addi- 
tion to the ordinary aspects of a foliated rock, has a peculiar slicken- 
sided look, as though it had been subjected to great compression long 
after it had become a normal mica-schist. 
3. Prawle Point and the adjacent Coast. 
Instead of continuing the section westward from the Start light- 
house, it will, I think, save time to describe next the rock which 
forms the fine headland of Prawle Point, and then to follow the coast 
back to the Start, on the eastern, and to Portlemouth on the western 
side. The first rock seen after quitting the village of Hast Prawle 
for the Point, is a mica-schist presenting a general resemblance to 
that atthe Start. It formsa sort of scarp running westward, on the 
southern slope of the hilly upland. Apparently emerging from 
