Page:The Zoologist, 4th series, vol 5 (1901).djvu/89

Rh of York, here called wolds, do not reach to the coast, but form, where the Yorkshire water system combines to form the Humber, a large alluvial tract of country known as the Holderness.

The geology of the county is of a varied character; the limestones and shales form the mountain masses in the north-west, and are succeeded in the south-east by the millstone grit formation; whilst west and south-west of the central vale the carboniferous system attains its maximum development. In the west the Silurian occasionally crops up, and a belt of lias skirts the coast south of Whitby, and after a very circuitous course comes into contact with the chalk near Market Weighton. As might be expected from such a diversity of physical conditions, the climate varies greatly, being dry and bleak in the east, comparatively mild in the central vale; whilst the elevated portions of the west and north-west are marked by a tolerably healthy climate, but are swept by high winds, and have a heavy rainfall. This is well shown by the fact that while the mean annual rainfall of the east is 26 inches, that of the west is 36·44 inches. This heavy rainfall in the West Riding is probably due to the land there being aggregated in mountain masses, and as the prevalent winds are from the west and south-west, they come laden with aqueous vapour, which, on coming into contact with the high ground, is precipitated as rain. This excessive rainfall and low temperature may account to some extent for the absence or extreme scarcity of a few of our summer migrants in the north-west fells.

The Stonechat in Yorkshire used to be regarded as "common and generally distributed in suitable localities"; but, if so once, is so no longer, and is now both local and scarce, and very erratic in its distribution. It is, however, highly probable, if not certain, that formerly it was commoner than at present, at least in the north-western portion of the county, and it is to be feared that, as a breeding species, it is dying out. In this district (Wilsden) I am not aware of its having bred for over thirty years, which is very strange, as gorse is quite common on the waste lands, and flourishes up to 1000 ft.

An old friend once told me that he found what he took to be the nest of the Stonechat near here, which must be forty if not fifty years ago. This instance, and another recorded by Mr.