RANGE OF PLIOCENE STRATA. 651 times grouped into beds, and sometimes exhibiting oblique and dis ordered laminae or false bedding, very much resembling the general character of a modern shelly beach. And from the manner in which it lies in the country about Ipswich and at Bramerton, there can be little doubt that it was deposited as an ancient beach of the German Ocean. But about Aidborough and Orford the Crag assumes a totally different character, becoming an organic accretionary shelly limestone, formed by the cementation of the Polyzoa and other groups, with shells and calcareous sand. This coralline deposit contains some of the most characteristic shells of the Coralline Crag. The Crag deposits have hitherto been arranged under the three following groups :— Upper group or Fluvio-marine Crag of the vicinity of Norwich, &c. Mammalia, littoral shells, &c. Middle group or Red Crag of Suffolk. Mammalia, reptiles, fish, and multitudes of invertebrata, often much waterworn. Lower group or Coralline Crag of Suffolk. Few or no mammalia, and abundance of invertebrata, not waterworn. Late research, however, by Messrs. S. V. Wood and S. V. Wood, jun., F. W. Harmer, Professor Prestwich, the Rev. 0. Fisher, Messrs. R. and A. Bell, and the officers of the Geological Survey (Messrs. H. B. Wood ward, C. Reid, and Blake), have greatly added to our knowledge of the Pliocene deposits of the type areas, and the following stratigraphi cal divisions are now generally adopted :— 5. The Bure Valley Beds 1= Lower Glacial of Messrs. Wood and Harmer. 4. Chillesford Beds = The Laminated series. 3. Fluvio-Marine Crag=The Newer Pliocene. 2. Red Crag. I. Coralline Crag. The only European area in which Pliocene strata attain any considerable dimensions as rock-masses, is the region of the Mediter ranean. This development takes place along both flanks of the Apennine Chain and in Sicily, and reaches a thickness of several thousand feet, an accumulation deposited during the slow and con tinued depression of the sea-bed of the Mediterranean. Climatic Changes in the Pliocene Period.—The general character of the flora and fauna shows without much doubt that a land passage must have existed between Britain and the Continent in pre-glacial times, so as to allow of the immigration of the plants and animals whose remains occur under the glacial deposits of the Norfolk coast. As far as evidence goes in pre-glacial ages, Britain stood higher rela tively to the sea than at present. At this time also it is probable that no German Ocean existed, and the English Channel may also have been in the condition of dry land. Pre-glacial Britain therefore formed part of the European Continent, supporting a vegetation similar 1 The term “ Icenian ” was proposed by Dr. S. P. Woodward for the Pliocene strata, their order of succession having been determined in the Eastern counties of England, the country of the Iceni.