On the Landslips of the River Tamar. 
359 
water, which was in general extremely turbid, caused by the clay 
of which the subsoil of the hill was composed ; deep hollows were 
also to be often met with apparently caused by the perpendicular 
sinking of the land, consequent upon the moving of the subsoil; 
in other cases, which were the more general, the land slipped down 
the inclined plane towards the river, until it met with resistance 
from firmer ground in its way or at the base, when it either 
abruptly rose, or, by its momentum of descent, insinuated itself 
between the fundamental rock and the superficial soil, forcing 
the latter above'its usual level into irregular hillocks, but of a 
very unstable character. In other cases, as at Freshwater Point, 
the residence of Mr. Wm. Griffiths, the disengaged mass of 
earth descends to the beach (the lowest moving stratum being a 
pipe-clay), which at a short distance below its surface is composed 
of greenstone, the prevailing rock on the bank of the river. In 
this instance the lower land is upraised by the moving stratum 
forcing itself, as already mentioned, beneath the soil at the water’s 
edge, so as to cause a fence erected on this lower land to be lifted 
up in some parts many feet. The devastation at this beautiful 
point of land has been most lamentable, the slipping and sinking 
of the superficial soil having taken with it all the large and 
valuable fruit trees that were planted either on it or in its way, 
and threatens with ruin a large brick building erected on the brow 
of the hill a little above where the landslip has taken place. 
It is remarkable that the eastern bank of the Tamar has not 
suffered, except in very few slight instances, from this destructive 
agent. This may be accounted for in several ways—viz., the land 
is less precipitous; the surface has been less disturbed so as to 
permit the absorption of water; and lastly, the greenstone rock 
lies much nearer to the surface—often projecting above it—thus 
offering a permanent barrier to the moving of the ground; as in 
no case have I found the rock in any way affected. 
I have no difficulty in attributing these landslips to the natural 
consequences resulting from breaking up the surface soil by culti¬ 
vation, whereby the rain, instead of running over the hard compact 
native turf, penetrates the soil, now open for the reception of 
whatever water may fall upon in, and percolates through the ground 
