C. L. Walton 
23:3 
the host snail. The work in 1913-14 was of a preliminary character 
and the grant from the Board of Agriculture and Fisheries was renewed 
and increased for 1914-15 and again renewed for 1915-16. 
It speedily became evident that no hard and fast boundary line 
could be adopted, and while particular attention was given to the Area 
as defined for the other Surveys (Geological, Botanical, Economic, etc.) 
yet I did not hesitate to go further afield in order to gain a more com¬ 
prehensive view of the problems, and to obtain additional data. In 
fact, had this not been done, one of the districts most affected by 
Liver Rot, and, at the same time most typical of much of Mid Wales 
would have been overlooked, since it commences at the very margin 
of the original sheet selected for investigation: Ordnance Survey 163 
(small sheet series). Further, several groups of farms were examined 
well outside the Area to act as “controls” and for purposes of contrast. 
Such groups were examined at (a) Kerry, Montgomeryshire; (b) 
Llandrindod Wells, Radnorshire, and again a few about Llanddewibrefi 
and neighbourhood somewhat to the South of the Survey Area, in South 
Cardiganshire. 
Topography of the Aberystwyth Area. 
The Area surveyed comprised North Cardiganshire and some 
adjacent borders of Montgomeryshire, and may be roughly defined as 
0. S. sheet 69 (large sheet series) excluding the portion of Merioneth¬ 
shire in the N.w. and, roughly, an eight mile wide strip of country 
running N. and s. to the extreme E. of the sheet; though the Area also 
included a few farms lying to the south of the sheet. Roughly the 
boundaries are: 
To the w. and N.w. (coast and river) 22 miles 
,, North ... ... ... 8 ,, 
,, East ... ... ... 18 ,, 
,, South ... ... ... 16 ,, 
say 250 square miles. 
The surface Geology of this area may be broadly described as 
follows in three main divisions— 
I. The mountainous upland tract of solid rocks frequently covered 
by a considerable depth of peat. The rock succession is only irregularly 
exposed in deep stream cuttings, while these valleys are occupied by 
boulder clay and river deposits. 
