Triassic Rocks of South Wales and the South-west of England

RHETIC OR PENARTH BEDS

Liassic

LOWER LIAS

MIDDLE LIAS.

UPPER LIAS

Oolitic

Lower Oontic.

Table showing the Subdivisions of the Lower Oolitic Rocks.

MIDFORD SANDS

NORTHAMPTON SANDS AND LOWER ESTUARINE SERIES

. 167

168

171

Yorkshire-Bridlington Crag-Drifts of South Wales and

the South-west of England-Norfolk-Hessle and

Kelsea Beds-Brickearth of the Nar-North Wales

and Lancashire-Sussex

a

€ 309

309

309

311

313

314

314

Alluvium, Brickearth and Gravel-Lancashire-South-

west of England, &c.-Romney Marsh-Holderness-

Fenland, &c.-Copford, Clacton, &c.-Thames Valley

-Geology and Archæology, Flint Implements, &c.

326

SOILS. Warp and Trail-Clay-with-Flints-Mould-Terraces. 359

GREY WETHERS

363

CHAPTER XII.

IGNEOUS AND METAMORPHIC ROCKS-MINERAL VEINS.

Classification of Igneous and Metamorphic Rocks, by F. Rutley-General

account of Igneous and Metamorphic Rocks

MINERAL VEINS. Iron Ores-Lead Ores-Zinc Ores-Copper Ores-Tin

Ore-Gold-Manganese Ores-Plumbago

CHAPTER XIII.

DENUDATION AND SCENERY.

Causes and Effects of Denudation-Coast Line-Islands-Inland Features

-Hills-Vales-Plains-Plains of Marine Denudation-Escarpments

-River Valleys-Escarpments and Cliffs-Denudation of Weald-

Lakes Waterfalls- Cheddar Cliffs-Weathering of Limestone-Tors,

Logan Stones, &c.-Forests-Influence of Man

. 365

382

387

NOTES ON FEATURES OBSERVABLE ON THE MAIN LINES OF RAILWAY. Great

Eastern Railway-Great Northern Railway-Midland Railway-

London and North-Western Railway-Great Western Railway-

London and South-Western Railway, &c.

413

CHAPTER XIV.

GEOLOGY IN THE FIELD-ITS ECONOMIC AND SCIENTIFIC

BEARINGS-CONCLUSION.

Petrological or Structural Features-Faults and Disturbances--Economic

Bearings of Geology-Scientific Bearings of Geology-Darwinian

Theory-Antiquity of Man-Conclusion

PAGE

420

APPENDIX.

A. Glossary of Terms and Addenda

437

B. Synopsis of the Animal Kingdom with especial reference to Fossil

As the Map accompanying this volume differs in some respects from other
geological maps of England and Wales, it may be well briefly to indicate the
changes introduced.

The index of colours has been arranged to show the comparative thicknesses
of the formations.

The Cambrian and Silurian rocks are classified according to Sedgwick, so
that the former group includes the Lower Silurian of Murchison.

The Devonian rocks are shown in the index as representing portions of both
Old Red Sandstone and Lower Carboniferous Rocks, which seems to be their
true position in the geological scale.

The Neocomian (Wealden and Lower Greensand) or Lower Cretaceous
strata are separated from the true or Upper Cretaceous strata.

The Drift deposits (Boulder Clay and Gravels) which it is attempted to
show, comprise a very small portion of those which are scattered over the greater
part of the country; but as yet they have been mapped only in certain
areas where they are perhaps most extensively developed, and these areas are
shown. It must be remembered, however, that while they obscure so much of
the Chalk and Tertiary strata in the Eastern counties, these older deposits are
generally exposed in the valleys, although in tracts too small to display them
upon the Map.