OF THE FORTH DISTRICT. 427 
sand, gravel, and till-clays, emerge from under the carse- 
clay at its margin on all sides, ascending often to an eleva- 
tion considerably above it, forming knolls, ridges, and in- 
clined planes. On the Map, the carse-grounds are expressed 
by yellow^ the sands and gravels by pink. The bounding 
line is discontinued at those points of the last, where parti- 
cular observation has not been extended. 
On digging these wells sundry vegetable remains were 
observed, consisting of wood, hazel-nuts, and leaves of trees, 
in good preservation, occurring at various depths, interstra- 
tified with large gravel, clay, sandy clay, and sand, the 
last furnishing abundance of water, to which the clay may 
be considered as impervious. There are similar appear^ 
ances at Drip, in the upper district, in passing fourteen feet 
through the clay into sand, reposing on the margin of a 
knoll of red sandstone. At Alloa, also, timber and other 
land products occur in sinking pit-shafts through the carse- 
clay to the coal-rocks. In that quarter, and at the mouth 
of the Carron, some transference of the soil may be sup- 
posed to have occurred, and a portion of the soft clay, or 
sludge, uncovered at every tide, may have been deposited 
in natural hollows. At Alloa, the tides form rapid currents 
during a pc« tion of every efflux and reflux. But in other 
places, w^here the surface presents small depressions, not 
exposed to be flooded by any considerable stream, the clay 
immediately under the vegetable mould is a fine tint of blue, 
indicating that it had suffered no disturbance or mixture. 
Of this description, at B on the Map, occupying a small 
plain on the margin of the Carse, slightly depressed, is 
that in which the skeleton of the whale was imbedded, at 
Airthry. Hardly above the level of the river, from whicli 
it is separated by more elevated ground, a small rill passes 
from the adjoining hill, which, stagnating, may have pro- 
duced the covering of peat-earth, r/iuch thinner than the 
