Kitroe— Zhe Distribution of Drift in Ireland. 427 
the fertile district skirting Bantry Bay, where a thick deposit of 
Limestone Boulder-clay is to be found, and of the country stretching 
_ north-eastward by Newbliss in the county of Monaghan, where a 
good soil rests upon unpropitious Silurian rock. 
An advantage, which should not be lost sight of, attaches to 
the transportation of limestone débris to areas where it does not 
form part of the solid crust, namely the abundant supply of 
limestone boulders, for burning for agricultural and other purposes, 
which is readily procurable from the deeper portions of the drift 
in such places. 
Nutriment may be drawn from considerable depths by such 
plants as lucern and sainfoin; and, through capillarity, fertilizing 
constituents in solution may be placed within reach of ordinary 
plants; yet it is manifest that ordinary herbage and rotation crops 
are mostly dependent upon the uppermost two or three feet of the 
soil and subsoil. A layer of clay, therefore, which might be over- 
looked in deep sections of drift, may, to the agriculturist, be a 
matter of prosperity or the reverse. 
As a general rule the uppermost layer of clay, even when it 
rests upon another Boulder-clay, is derived chiefly from the rocks 
of the immediate locality, which appear here and there through 
the drift—mingled with material derived from the Lower clay, and 
those carried from higher grounds adjoining. This will be seen 
by reference to soils and subsoils at Rathdrum, Glenealy, Baltin- 
_ glass; and at other localities, also mentioned in the table, in the 
eounties of ‘l'yrone and Fermanagh. 
In many places, especially in the higher grounds, the soils and 
subsoils have doubtless been formed by the disintegration of rock | 
in situ; and it becomes difficult to say where this runs into true 
drift. The latter is easily recognizable, however, when it rests 
(1) upon a glaciated surface; or (2) upon a Lower Boulder deposit ; 
or when it is (3) intermingled with foreign rock detritus, or 
(4) contains glaciated boulders. 
I add a few remarks upon the appended Table. In estimating 
the proportion of stones in a soil, with a view to the preparation of 
such a'l'able, to reckon only the boulders does not give a true idea 
of the soil contents; for numerous small fragments affect its 
character, it is needless to say, more than a few large ones; and 
the frequent occurrence of boulders of a certain kind does not 
