360 
On the Landslips of the River Tamar. 
until it meets with the argillaceous substratum. The clay becomes 
saturated, forming a semi-fluid slippery paste, and thus the super¬ 
incumbent earth, losing its firm subterranean support, naturally 
slips downhill wherever the angle is sufficiently great, taking with 
it trees, houses, fences, or whatever may be upon it. I am the 
more confirmed in this opinion, from the circumstance that it has 
taken place only where the surface of the ground has been broken 
up above or at the place of mischief, either by ploughing or by 
taking up the trees by the roots, when the excavations formed by 
this latter process become receptacles for water, and produce a 
similar effect. This is exemplified at Marion farm (the residence 
of Mr. Meara), Spring Bay, and still more strikingly about a mile 
and a half below, in which the effects of recent cultivation is more 
apparent from the greater steepness of the land. 
A remedy is not so easily suggested, and I fear nothing is left to 
the proprietors of these farms with a view to the prevention of the 
evil in future, but to form deep drains above the land to be culti¬ 
vated or broken up, so as effectually to carry off the whole of the 
rain that may fall above it on the hill-side, in the most direct line 
to the river, without running over the lower landswhere, how¬ 
ever, lands must necessarily be cultivated, they should in addition 
be well drained, both by under and surface drains. In cases 
where any valuable house or plantation of trees may be already 
situated on the brow of a steep descent, I would suggest the surface 
should be left intact; or, if already broken up, that it should be 
immediately laid down in close permanent pasture and well rolled 
so as to permit the rain to remain on it as short a time as possible. 
The deep drain above, which I have already recommended 
forming an additional precaution. 
I think it unnecessary to multiply my observations on this 
subject, as the evil is necessarily under the immediate eye of those 
who most suffer by it, but I strongly recommend the antidote to 
be applied as soon as possible, as by its nature the mischief must 
assuredly increase. 
George Town, 1 5th October, 1847. 
