212 
Part III. — Eighth Annual Report 
In the New Statistical Account, the Rev. Alexander Nicholson, 
minister of the parish of Barra, tells that 'cockles are to be found 
1 (1845) in the sands of Barray in such immense quantities that scores 
• of horse-loads may be taken up during a single tide.' 
These are some of the samples of the prominent position which the 
cockles of Barra held in the estimation of the writers on Barra between 
1540 and 1845, and no account of the island is complete without a 
reference to the valuable cockle beds of Barra. While cockles are 
plentiful in such localities as Benbecula, Lewis, Easter Ross, St 
Andrews, and Solway in none of these can such quantities of fine 
cockles be obtained as in Barra. 
2. The Cockle and its Habits. 
The cockles — genus Cardium—have a wide geological range, ex- 
tending from mesozoic times through Tertiary strata and into the seas 
of the present day. While the species that existed in Secondary and 
Earlier Tertiary ages present the characteristic features of the genus, 
individuals exhibiting the specific characters of Cardium edule are 
found in the Coralline Crag of the Pliocene, and in succeeding Pliocene 
strata down to the raised beaches that are so well developed on different 
parts of our shores. Jeffrey * has also chronicled the presence of fossils 
of G. edule from Upper Miocene strata near Antibes. Like its fellow 
Lamellibranch — the common mussel — the life of the species C. edule has 
been a long one, but its ancestral history is even longer than that of 
Mytilus edulis, which occurs only in the Upper Tertiaries. 
Corresponding with this wide distribution in time, the common 
eiible cockle, like the edible mussel, is found in the North Atlantic 
from the Polar circle to the waters of the Mediterranean, Mohr chronicling 
its occurrence in Iceland, and Forbes in the iEgean. It has also been 
found in the Canaries. 
Some of the species of the genus Cardium are found at consider- 
able depths, but the common cockle abounds in sandy beaches close in- 
shore. It is found in beaches above low- water mark, and also in sandy 
bays a few fathoms in depth. While it flourishes best, and attains its 
greatest size in salt water, it is also present in the brackish water of 
estuaries. In the latter case, however, it exists as the smaller variety 
— rusticum — much smaller in size, and with a more delicate and wedge- 
shaped shell. 
The ground in which cockles are found is sandy and soft, and the 
common cockle is generally buried from one to a few inches below the 
surface of the bank. If the sand is too soft and easily disturbed by 
the waves, the cockle is not able to maintain a vigorous foothold, 
whereas too hard ground presents an obstacle to its movements in the 
sand. While cockles herd together in great numbers, it is only in 
sheltered bays that they are obtained in sufficient numbers to make the 
gathering of them a commercial success. Where the sands are exposed 
to the full force of the Atlantic and North Sea waves, they are practi- 
cally barren. Even storms in what are regarded as sheltered bays 
often cast ashore great quantities of cockles and their more seaward 
neighbours — razor-fish (Solen). The latter generally is found in the 
sand in a more or less vertical position, but the position of the cockle 
is not nearly so constant. If cockles are left on the surface of a sand 
bank, they bore their way obliquely downwards and have the beak of 
* British Conchology, vol. ii. p. 287. 
