556 
Agriadture of North Wales. 
Ruthin and proceeding southward until we come to the rise at 
Cricor Mawr, gradually becomes more friable by an increased 
intermixture of sand, changing from the lower part of the vale to 
the highest from a stiff loam through all the gradations of sandy 
loam till the same merges into a deep red coloured sand, held 
together by a small amount of aluminous and vegetable matter. 
Following the course of the Clwyd from Ruthin to the north- 
ward, the vale gradually expands, and the soil becomes stiffer and 
continues as we proceed to the northward to indicate the presence 
in increased proportion of aluminous matter until we arrive at the 
northern extremity of the vale, which is bounded by the Irish 
Sea, at some distance from whose margin the soil assumes the 
well known appearance of warp-land. 
The fertility of the vale of Clwyd has been proverbial ; and 
perhaps no better opportunity could be taken to examine the 
reasons why the vale of Clwyd, which extends to the westward of 
the Clwydian range, should be found and is esteemed so much 
more fertile than the vale of Wrexham, which lies to the east of 
the same range. It has been previously remarked that the soil 
of the vale on the western side of the Clwydian range is more 
friable than that on the eastei-n, in consequence of which it is 
much more permeable to moisture, which is speeddy absorbed by 
the red-sandstone underneath, or carried away by the various 
fissures of the subjacent rock ; on the other hand, on the eastern 
side the soil is extremely thick, and somewhat impermeable, 'i'he 
difference of temperature caused by the absorption of heat by 
the evaporation of so much more moisture in proportion to its 
extent, combined with the prejudicial influence of a redundancy 
of moisture in the soil, will, in the absence of a perfect system of 
drainage, account materially for the western exceeding the eastern 
side of the range in fertility. In addition to the preceding, 
there are other causes ; the vale of Clwyd is bounded on every 
side except the north by hills, most of which are of considerable 
elevation, whilst the vale of Wrexham is only sheltered from the 
most genial wind that blows — the Avestern : the cold cutting 
north-eastern winds so prejudicial to vegetation, especially in 
spring, are scarcely ever felt in the vale of Clwyd ; the direct north 
wind seldom blows, and when it does, though it may be boisterous, 
the temperature is much ameliorated by passing over the unin- 
terrupted expanse of the Northern and Irish Seas. 
On the limestone hills, which are intermixed and surround the 
two vales just described, it may be stated that the short ridge 
extending between Llangollen and Cyrn y Brain are ])recipitous 
and almost bare of soil from the base to the summit; the grass 
growing on it is analogous to that grown on other limestone dis- 
tricts, and is well adapted to the rearing of South-down sheep, 
