174 
POPULAR SCIENCE REVIEW. 
in soil that overlies a deposit that has been, by our ablest geolo- 
gists, pronounced to be a raised sea-beach. 
The latest alteration of land upon this southern and western 
portion of the island, has been pronounced to be one of depres- 
sion, and that the latest preceding that movement was one of 
upheaving. The former is shown in the numerous submerged 
forests around our western and southern coasts, and the latter 
is demonstrated in the remains of extensive sea-beaches that 
exist all round our shores. 
It, therefore, would appear, that a careful study of the geolo- 
gical history of these formations, with which, in this locality, 
the flints are in connection, will assist materially towards our 
arrival at, at least, an approximation to the period at which the 
flints were deposited. 
The first important study will be the careful analytical examina- 
tion of the so-called raised sea-beach. This, as I have before said, 
exists between Baggy Point and Braunton Burrows, a distance 
of more than two miles, and rises from the present sea level to 
the height of about fifty feet. In some places, where the wash 
of the sea has been greatest, it is only to be met with in patches. 
This destruction has been carried to so great an extent near the 
spot where the flint flakes are most numerous, that a small high 
water island stands several yards off from the main land, the 
intervening ground having been washed away by the sea. 
Whereas, on the western side of Croyde Bay, it exists as a per- 
pendicular wall stretching a mile along the coast. This so-called 
raised sea-beach consists of fine sand mixed with a few shells 
and pebbles towards the lower portion, the general aspect 
being a series of horizontal layers ; while a closer inspection 
shows that these horizontal layers are built up by numerous thin 
strata exhibiting lines of false bedding in various directions. In 
the upper beds the stone is soft and friable, while in the lower 
it is hard and firmly cemented together, so that it is not easily 
broken by the geologist’s hammer. In the upper layers the 
sand is generally free from extraneous objects, but towards the 
bottom a few shells and numerous pebbles of several kinds are 
found ; the shells, as far as my own experience goes, consist 
invariably of single valves, of mytilus edulis , the common 
mussel, to which, upon the authority of Professor Sedgwick 
and Sir Roderick Murchisson, those of cardium edule, the 
common cockle, patella vulgaris, the common limpet, solen , or 
razor shell, and donax truncatulus, of which list only three, the 
cockle, razor shell, and donax, can live where sand exists, and 
these most probably, as previously observed, are represented 
only by the remains of dead valves. 
The pebbles are found in the lower stratifications, the largest 
specimens being in the lowest, while a little higher, smaller spe- 
