PROCEEDINGS, 1871—1877. 
355 
towards Brierley, and the other lying around Ackworth and Ponte- 
fract, are more elevated, and afford some information. These higher 
gTounds are occupied by a thickly-bedded, softish sandstone, which 
Mr. Green named the Houghton Common Rock. Below this is a 
second thick bed of similar sandstone, which he named the Brierley 
Rock. It may be seen on the north around the village of Hems- 
worth, and on the south-west side at the village of Brierley. They 
were calculated to be at a distance of 560 yards and 680 yards 
respectively above the Barnsley Coal. Near Pontefract there are a 
couple of similar thickly-bedded, softish, light-brown sandstones. The 
lower is largely quarried, and forms the bold bluff on which stands 
the Castle. The upper is less conspicuous. These very much 
resemble, and, it is conjectured, are the equivalents of the Houghton 
Common and Brierley rocks. It is probable that the rocks over the 
whole district undulate gently in broad, shallow folds. In each basin 
an outlier of the upper sandstone occupies the centre, encircled more 
or less completely by tlie lower sandstone . For further details the 
author refers his hearers to a memoir on the Geology of the Yorkshire 
Coal-fields, then in preparation, and since published. 
At a meeting in 1876, held at Barnsley, Professor Green described 
a section of boulder-clay near Barnsley. The distribution of the drift on 
the eastern side of the Penine Chain is very limited. It is, however, 
not altogether absent, and scattered patches have been detected here 
and there over the district. One of the most remarkable of these he 
proceeded to describe. It was exposed while cutting a mineral rail- 
way near the Carlton Main Tollgate, on the Barnsley and Wakefield 
road, about two miles north of Barnsley. It consists of stiff", blue 
boulder-clay, occupying a hollow in the Woolley Edge rock. The 
clay contained small pebbles, mostly derived from the neighbouring 
rocks, but containing a few ice-scratched carboniferous limestone, 
chert, and trap rocks. Northwards this lower boulder-clay is covered 
by a deposit of what Professor Green denominated upper boulder-clay. 
It is more sandy, but has fewer stones. It is more or less bedded, 
contains interbedded laminated clays or warps. The warp is a 
bluish-brown, finel3^-laminated rough clay, with small, well-rounded 
pebbles of carboniferous sandstone and coal. Having described the 
