280 
POPULAR SCIENCE REVIEW. 
Looking at the physical structure of the south-western and 
north-western part of England, and the great mass of the older 
Palaeozoic rocks of North and South Wales, it is evident that 
from the Cheviots to Cornwall the oldest rocks in Europe are 
exposed, hidden only in places by a mantle of superficial glacial 
and river drifts. The eastern sides of the exposed Northum- 
berland and Yorkshire coalfields, down to the latitude of Not- 
tingham, are covered and deeply buried by the Triassic, Jurassic, 
and Cretaceous rocks ; south of Nottingham these old land areas 
are again exposed. The Charnwood rocks, of unknown age , 
and the associated coalfield of Ashby-de-la-Zouch, with the 
Warwickshire and South Staffordshire coalfields, stand out like 
islands in the midst of the great Triassic plain of mid-England ; 
they are the last isolated exposures or remnants of Palaeozoic 
land seen south and east of the great Pennine axis. 
The entire mass of North and South Wales stands out in bold 
relief westwards of the Severn Valley and the stunted hills of 
Cheshire. The Old Eed mountains and Silurian rocks which 
border the northern edge of the great Welsh coalfield, as well as 
the Devonian promontory of Cornwall, isolated as they appear 
to be through the unconformity of the Secondary rocks which 
constitute the eastern half of England, are only apparently so 
through this great overlap. Could we uncover and expose the 
old Palaeozoic floor or land surfaces on which they rest, with all 
its irregularities, doubtless we should find that the eastern face 
of the Palaeozoic plain would stretch away under the north-eastern 
and south-eastern counties and Grerman Ocean,* filling up the 
irregularities in the old land surface made either by the denuding 
agency of the secondary seas during the slow depression of the 
area they then occupied, or they were previously sculptured and 
fashioned into hills and valleys at the close of this early period, 
and prior to the deposition of the Secondary or Mesozoic rocks. 
The area on which the British Islands stand is an elevated yet 
submarine plateau, extending westwards from Ireland some 100 
miles, and eastwards to Holland, north to Scandinavia, and south- 
wards to a deep region west of France and Spain. The western 
face of this plateau, now beneath the sea-level and covered by 
the Atlantic, has a steep and rapid slope to the profound depths 
of that ocean. On the eastern side of England, on the other hand, 
the Grerman Ocean, with its irregularities of sea-bottom, scarcely 
averages 100 feet in depth, and this shallow sea and the east of 
England unites us to the European plain. It is upon this plateau 
that all those changes of level, great and small, change of life, 
* See Section No. 4, PI. VII. Ideal section by Professor Hall, showing the 
prolongation of the Silurian, Devonian, and Carboniferous rocks eastwards, 
and the probable irregular surface of the Palaeozoic rocks, now covered by 
nearer deposits. (“ Coal-fields of Great Britain,” p. 475). 
