On the White Chalk of Yorkshire

Abstract

The following notes are supplementary to the papers already published on the Red Chalk (1878), and on the origin and formation of the Wold Dales (1879.) The white chalk of Yorkshire differs considerably from the chalk of Kent and Sussex. In the first place, it is much harder, and in places almost crystalline. Then, the flint-bearing beds are the lowest in the Yorkshire series, whereas they are the highest in the southern; the upper beds in Yorkshire, forming the inner edge of the Wolds, have not a trace of flint. The flints too are different; in the north they are light-coloured and can be shattered by a blow into a thousand pieces, whilst in the south they are black, tough, hard, and compact. Numerous flint weapons, knives, arrow-heads, spear-heads, scrapers, &c., have been picked up on the surface of the Wolds, or extracted from the numerous tumuli, but they are almost invariably of foreign flint picked up probably on the sea shore, washed out of the Boulder Clay, the flint of Yorkshire not being adapted for the manufacture of flint weapons. A Frenchman, Mons. Barrois has attempted to divide the Chalk beds into a series of zones, containing characteristic fossils, but enough attention has not yet been paid to the subject, in Yorkshire at least, to prove or disprove the truth of his theory. It is certain, however, that very large ammonites are only found in the lower beds, and marsupites only in the highest, whilst on one horizon inocerami ...