Page:The South Staffordshire Coalfield - Joseph Beete Jukes - 1859.djvu/143

Rh found between the measures to the east for a distance of about two miles.

Pouk Hill.—Pouk Hill, near Walsall, is another mass of columnar basalt of less size than Barrow Hill, but equally, or still more, interesting.

It lies altogether below the Thick coal and between the Fireclay and the Bottom coal.

It formed a small slightly prominent mound of about 100 yards across, but this is now nearly all quarried away. The quarry, however, in 1858, exposed the structure of the rock in an admirable manner, and showed that structure to be very interesting and peculiar.

In the centre of the quarry the columns, which were often very regular, were vertical over a space of some 20 yards in diameter. In the middle part of this space the columns continued vertical till they reached the surface, but on the western side the tops of these vertical columns curved in for the space of a yard or so, and were at last quite sharply bent inwards so as to have the transverse section of the columns facing towards the centre of the quarry. The line along which this curvature took place sloped obliquely down from the top of the quarry to the floor at an angle of about 35°, and above that line all the columns lay in a position more nearly approaching the horizontal than the vertical. The ends of the columns slightly curved up along the line of junction so as to become nearly parallel to the bent tops of the vertical columns, and rose in the other direction into angle of about 20°, so as to suggest the idea of a radiation from this inclined line of junction.



On the eastern side of the quarry the columns likewise lay in slightly bent, but nearly horizontal lines, though here the change