400 Geological Society :— 
country was covered. This was the time of the marine drift with 
floating ice. The beds with arctic shells belonged to it, and some 
of the brick-clays are probably but the fine mud of the deeper 
parts of the same sea-bottom. 8rdly. The land emerged from the 
water, during which emergence the preceding drift-beds suffered 
much denudation, giving rise to the extensive superficial accumula- 
tions of water-rolled gravel that now overspread much of the sur- 
face. ‘This movement continued until the land obtained a higher 
position than it now has, and became connected with the continent 
of Europe. Its various islands were probably also more or less in 
conjunction. The present assemblage of animals and plants gra- 
dually migrated hither from adjoining lands. Glaciers may have 
still been formed in favourable places, but probably never regained 
their former extension. 4thly. The land sank again until the sea 
in most places reached a height of from 30 to 40 feet above the 
present tide-mark. Patches of forest-ground were submerged along 
the coast. The clays and beds of silt, forming the ‘‘ carses ” of the 
Forth, Tay, and other rivers, were accumulated, as well as the post- 
tertiary beds of the Clyde, &c., described by Mr. James Smith, the 
shells of which agree with those of our present seas. Sthly. An 
elevation at length took place, by which the land attained its present 
level. As Mr. Smith has shown, this probably occurred before the 
Roman invasion: but that man had previously got into the country 
appears from the fact that the elevated beds of silt near Glasgow, 
contain overturned and swamped canoes with stone implements. 
February 29, 1860.—L. Horner, Esq., President in the Chair. 
The following communication was read :— 
“‘On the Lower Lias of the South of England.” By Dr. T. 
Wright, F.G.S. 
The author first stated that the uppermost beds of the Lower Lias 
are those containing Hippopodium ponderosum, and that the lowest 
beds are those with Ammonites Planorbis, overlying a series of strata 
containing Estheria, &c., which he separates from the Lias, under 
the name of the Avicula contorta beds. The last rest on the grey 
and red marls of the Keuper. 
Dr. Wright then proceeded with the description of the A. con- 
torta beds, including the “ Bone-bed,” having first enumerated the 
authors who have written on these and the equivalent strata (Kos- 
sener Schichten, &c.) on the Continent. The sections at Garden 
Cliff, near Westbury on the Severn, at Wainlode Cliff, at Aust Cliff, 
at Penarth near Cardiff, at Uphill near Weston-super-Mare, at Cul- 
verhole near Axmouth, at Wilmcote and Binton near Stratford-on- 
Avon, were described in detail as illustrating this series ; and General 
Portlock’s section of these beds in the North of Ireland was also 
alluded to. Pecten Valoniensis, Cardium Rheticum, and Avicula con- 
torta are the chief molluscan fossils of this zone. 
The next group of strata are those with Ammonites Planorbis and 
Am. Johnstoni. Some of the foregoing sections expose these beds, 
such as those at Uphill and Wilmcote; but they can be still better 
studied at Street in Somersetshire, where they have yielded so 
