352 MANUAL OF GEOLOGY. TABLE LI.—Equivalents of the Jurassic Series, -British and Foreign. British Divisions. Foreign Equivalents. I. Lower Lias. 2. Marlstone 3* Upper Lias. U2 Oxfordien Inferieur, part of 8. Oxford Clay 9. Coral Rag. O Terrain argovien, Terrain h, thon, Impressa kalke, Spongi- p b 5. Fuller’s Earth. 6. Great Oolite... 7. Cornbrash 8a Terrain Bathonien, Calcaire de Caen et Ranville. Parkinsoni bank, part of Brown Jura. ten layer—part of Brown Jura and Lower White Jura. Terrain Corallien, Schistes de Nattheim, Calcaire a nrinees. Middle White Jura. [The lithographic flags of Solenhofen are of this or Kimmeridge age]. 4. Inferior Oolite... Terrain Bajocien, Calcaire Ldonien, Calcaire h polypien, marnes Vsuliennes, Eisen-Rogenstein, discoidien mergel, Middle Brown Jura. Terrain Callovien, Brown Jura. Terrain Oxfordien, Chailies, Ornaten . Terrain Sinmurien, Grs du Luxembourg, Calcaire de Valognes, Grs de Lincksfield, Gryphiten kalk, Lower Black Jura. . Terrain liassien, marnes de Balingen, amaltheen- thon, numismalen mergel, Middle Black Jura. Terrain toarcien schistes de Boll, Posidonomya Schiefer, Jurensis mergel, Opalinus thon, Upper Black Jura and Lower Brown Jura. IO. Kimmeridge.... Terrain Kimridgien, argilles noirs de Honfleur, marnes du Baun, Calcaire h Astartes ; part of the Terrain Portlandien of the geologists of the Swiss Jura, who call the lower part Terrain Se- quanien ; part of Upper White Jura. II. Portland beds... Terrain Portlandien, Upper White Jura; Upper White Jura, Calcaire a tortues de Soleure. \I2. Purbeck beds.... Purbeckien. Relative and Local Thickness.—Although these successional groups and sub-formations give the normal and true succession of the Jurassic series throughout Britain, and more or less throughout Con tinental Europe, it by no means follows that they always rest one upon the other in any given area and have the same thickness, or are under the same physical aspects, or always contain the same fossil remains in any given section. As a rule, however, the same bed, or set of beds, traced along their strike and against or along some older shore or coast, do (under given conditions, such as depth, sedimenta- tion, temperature, and sustenance) exhibit much the same fauna, or one special to the time of deposition and the then existing conditions. Thickness has little to do with time deposits, and difficulties meet us everywhere when space is concerned. We may illustrate this through the Inferior Oolite, which attains a maximum thickness in the Cottes- wolds in the Cheltenham area, where at Cleve Cloud, Leckhampton, and the Stroud area, the series attain to the thickness of nearly 500 feet; the whole being readily divided or classified through the vertical or time distribution of certain species of Ammonites. These, however diversified the beds themselves may be through a given