117 
indeed the rocks from which they are derived do not contain 
on an average more than two per cent, of either alumina or 
silica ; the remaining portion being magnesia and lime. 
They, however, possess some useful qualifications : the farmer 
is seldom prevented performing for a long continuance the 
operations of farming, and the land soon regains its usual 
dryness after rain ; the labour required is also less than upon 
tenacious clays ; the weeds are not very numerous, and may 
with little labour be eradicated. The following list given me 
by Sir Francis Wood, are the most prevalent, and therefore, 
on their account alone, fallowing is not so frequently required. 
The elevation of the highest portions of the formation do not 
much exceed 500 feet above the sea ; 350 is the average ; the 
climate is temperate, and the season of harvest earlier by 
seven or ten days, than on either the Western Coal series or 
the Eastern plain of the New Red Sandstone. The disadvan- 
tao-eous circumstances attendino^ the cultivation of this land 
are the necessity of frequent manuring and the liability of 
the growing crops to suffer from extreme drought in summer. 
The quality of the upper. bed is in some respects superior to 
that of the lower, and will produce of wheat eight to ten 
loads per acre, and of barley four and a half to six quarters ; 
but some single fields near Norton, have produced as much 
as seventeen loads of wheat per acre. The lower bed is 
better adapted for the pasturage of sheep upon the turnips, 
but the soils upon both of the beds suffer materially if sheep 
are fed on late in the year, for the soils become kneaded or 
puddled into a stiff paste by the feet of these animals, and 
hence turnips cannot be fed off after January, without con- 
siderable risk of not being able to render the land sufficiently 
pulverulent for the ensuing crop of barley. Croskill's clod- 
crusher, which is formed by a number of loose iron dentated 
wheels, fixed upon a revolving axle, is a very useful imple- 
ment for the reduction of land after turnips. It is an 
