C. L. Walton 
207 
the area; this land is frequently rough and ill-drained, and the numerous 
streams traversing it often occupy deep ravines or cwms. The coastal 
plateau contains the best cultivated agricultural land, and also, naturally, 
the bulk of the population. The chief rivers of the Area are the Dyfi 
(the estuarine portion of which bounds Cardiganshire to the north and 
receives a number of mountain streams) the Rheidol and the Ystwyth, 
while to the south-east the watershed of the Teify is reached. 
The rainfall of the whole Area is considerable, increasing as the 
mountains are approached, and varying from 31 to 42 inches at 
Aberystwyth, 41 to 56 at Clogerddan and 48 to 70 at Hafod (near 
Devils Bridge), while Plynlymon receives from 90 to over 100 inches 
annually. From the point of view of the Agricultural Zoologist the 
area surveyed is divisible into six chief divisions, each with its own 
typical pests and diseases, varying with the elevation, type of soil, 
amount of rainfall, degree of cultivation and population, and kind of 
stock predominating. Much of the Area is rough and relatively in¬ 
accessible, and the examination of the sheep walks, etc, entailed a very 
considerable amount of arduous walking, especially during the winter. 
Throughout the Survey first place was given to field work, and in all 
some 250 different farms and holdings were visited, and as a rule 
examined. 
In general the farming does not reach a high level, the character of 
the land and climate in many cases being adverse, and the farm buildings 
frequently sadly inadequate, though there are, of course, a number of 
notable exceptions to the above general statements. Sheep farming 
and cattle rearing naturally predominate; agriculture being chiefly 
accessory. In addition to the parasites and pests described, some 
details of the local sheep farming, etc. are given. 
Gid ( Multiceps multioeps). 
This disease is one of the most troublesome to sheep farmers within 
the Area, and though rarely the cause of heavy losses, is a constant 
source of annoyance. Considerable attention has been given to the 
matter of its distribution, etc. and in order to understand its occur¬ 
rence it is needful to make a short resume of the various types of 
sheep farming practised within the Survey Area and the adjacent 
country. 
The Area is a wide one and comprises very diverse types of country, 
roughly divisible as follows: 
14—2 
