In another diagram (Fig. 85), a real section of the geological formations in the neighbourhood of Bristol and the Mendip Hills is presented to the reader, as laid down on a true scale by Professor Ramsay, where the newer groups 1, 2, 3, 4 rest unconformably on the formations 5, 6, 7 and 8. At the southern end of the line of section we meet with the beds No. 3 (the New Red Sandstone) resting immediately on Nos. 7 and 8, while farther north as at Dundry Hill in Somersetshire, we behold eight groups superimposed one upon the other, comprising all the strata from the inferior Oolite, No. 1, to the coal and carboniferous limestone. The limited horizontal extension of the groups 1 and 2 is owing to denudation, as these formations end abruptly, and have left outlying patches to attest the fact of their having originally covered a much wider area. Section South of Bristol. In order, therefore, to establish a chronological succession of fossiliferous groups, a geologist must begin with a single section in which several sets of strata lie one upon the other. He must then trace these formations, by attention to their mineral character and fossils, continuously, as far as possible, from the starting-point. As often as he meets with new groups, he must ascertain by superposition their age relatively to those first examined, and thus learn how to intercalate them in a tabular arrangement of the whole. By this means the German, French, and English geologists have determined the succession of strata throughout a great part of Europe, and have adopted pretty generally the following groups, almost all of which have their representatives in the British Islands. Abridged General Table of Fossiliferous Strata. TABULAR VIEW OF THE FOSSILIFEROUS STRATA, SHOWING THE ORDER OF SUPERPOSITION OR CHRONOLOGICAL SUCCESSION OF THE PRINCIPAL GROUPS DESCRIBED IN THIS WORK. POST-TERTIARY EXAMPLES POST-TERTIARY EXAMPLES POST- TERTIARY 1. RECENT Shells and mammals, all of living species. British Clyde marine strata, with canoes (p. 146). Foreign Danish kitchen middens (p. 146). Lacustrine mud, with remains of Swiss lake-dwellings (p. 148). Marine strata inclosing Temple of Serapis, at Puzzuoli (p. 146). 2. POST- PLIOCENE. Shells, recent mammalia in part extinct. British Loam of Brixham cave, with flint implements and bones of extinct and living quadrupeds (p. 157) Drift near Salisbury, with bones of mammoth, Spermophilus, and stone implements (p. 161). Glacial drift of Scotland, with marine shells and remains of mammoth (p. 176. Erratics of Pagham and Selsey Bill (p. 182). Glacial drift of Wales, with marine fossil shells, about 1400 feet high, on Moel Tryfaen (p. 181). Foreign Dordogne caves of the reindeer period (p. 150). Older valley-gravels of Amiens, with flint implements and bones of extinct mammalia (p. 152). Loess of Rhine (p. 154). Ancient Nile-mud forming river-terraces (p. 154).