272 MIDLAND UNION OF NATURAL HISTORY SOCIETIES. Dec., 1891. 
Coventry, and westward, but in split up seams, as far, perhaps, 
as Coalbrookdale. Its existence to the east of our coalfield had 
already been proved at Sandwell and at Hamstead, where the 
Thick Coal had been found under the red rocks at a depth of 
1,800 feet, and it was not outside the limits of probability 
that a continuous coalfield would be found to exist below the 
red rocks from Flint on the one hand to Leicester on the other. 
Professor Lapwortli went on next to describe the rocks on 
which the coal measures rested. It was only within the last 
few years that they had been able to map these rocks, and 
they were now divided into Silurian, Ordovician, Cambrian, 
and Archaean. About the last they knew very little, but he 
might note Caer Caradoc and the Longmynd as peaks of 
Archaean rock ; and they rose up again at Malvern and Charn- 
wood, which gave the direction in which the mountains of the 
pre-carboniferous continent lay. Cambrian rocks were found 
at the Lickey, while the Silurian Limestones were prominent 
at Dudley. These Dudley Silurian limestone rocks stretched 
westward, and appeared again at Wenlock, while to the east¬ 
ward they had been traced into France, Germany, and Russia. 
These limy rocks had doubtless been laid down in very deep 
water, though not so deep as the present oceans ; and he need 
not tell them that their presence in proximity to the coal and 
ironstone of South Staffordshire had doubled the value of 
these deposits by reason of the usefulness of the limestone as 
a flux. Hitherto he had been speaking of stratified rocks, 
but there were other rocks in the neighbourhood of which he 
might say a word or two. There were the basaltic hills of 
Rowley, about two miles in length and 200 feet in thickness, 
underneath which the coal measures lay but little altered. 
The lava which formed these hills apparently came up through 
cracks caused by earth movements, and the same material 
was found here and there injected through the coal. It was 
greatly to the credit of the Dudley mining engineers that they 
had had the enterprise to sink shafts through the Rowley 
Hills in the scientific faith that the coal would be found below. 
Another interesting class of rocks in the neighbourhood of Dudley 
was that class of glacial origin. In times not so long ago, 
reckoned geologically, our district was believed to be covered 
with glaciers and iceslieets, from Scotland and North Wales, 
and on these were borne rocks which were exactly of the 
same kind as those in the South of Scotland, the Lake District, 
and in North Wales. After a few words on the great western 
and eastern faults, Dr. Lapworth said he hoped that a few 
thousands would be risked in the endeavour to find coal 
beyond them, and that he trusted, if found, it might be at such 
a depth that future engineering invention would allow of its 
