Tealby Series.—At Tealby, a village in the Lincolnshire Wolds, there crop out beneath the white chalk some non-fossiliferous ferruginous sands about twenty-feet thick, beneath which are beds of clay and limestone, about fifty feet thick, with an interesting suite of fossils, among which are _ Pecten cinctus_ (Fig. 285), from 9 to 12 inches in diameter, _ Ancyloceras Duvallei_ (Fig. 286), and some forty other shells, many of them common to the Middle Speeton clay, about to be mentioned. Mr. Judd remarks that as _Ammonites clypeiformis_ and _Terebratula hippopus_ characterise the Middle Neocomian of the Continent, it is to this stage that the Tealby series containing the same fossils may be assigned.[2] Fig. 285: Pecten cinctus. Fig. 286: Ancyloceras (Crioceras) Duvallei. The middle division of the Speeton clay, occurring at Speeton below the cement-bed, before alluded to, is 150 feet thick, and contains about 39 species of mollusca, half of which are common to the overlying clay. Among the peculiar shells, _Pecten cinctus_ (Fig. 285) and _Ancyloceras (Crioceras) Duvallei_ (Fig. 286) occur. LOWER NEOCOMIAN. In the lower division of the Speeton clay, 200 feet thick, 46 species of mollusca have been found, and three divisions, each characterised by its peculiar ammonite, have been noticed by Mr. Judd. The central zone is marked by _Ammonites Noricus_ (see Fig. 287). On the Continent these beds are well-known by their corresponding fossils, the Hils clay and conglomerate of the north of Germany agreeing with the Middle and Lower Speeton, the latter of which, with the same mineral characters and fossils as in Yorkshire, is also found in the little island of Heligoland. Yellow limestone, which I have myself seen near Neuchatel, in Switzerland, represents the Lower Neocomian at Speeton. Fig. 287: Ammonites Noricus. WEALDEN FORMATION. Beneath the Atherfield clay or Upper Neocomian of the S.E. of England, a fresh-water formation is found, called the Wealden, which, although it occupies a small horizontal area in Europe, as compared to the White Chalk and the marine Neocomian beds, is nevertheless of great geological interest, since the imbedded remains give us some insight into the nature of the terrestrial fauna and flora of the Lower Cretaceous epoch. The name of Wealden was given to this group because it was first studied in parts of Kent, Surrey, and Sussex, called the Weald; and we are indebted to Dr. Mantell for having shown, in 1822, in his “Geology of Sussex,” that the whole group was of fluviatile origin. In proof of this he called attention to the entire absence of Ammonites, Belemnites, Brachiopoda, Echinodermata, Corals, and other marine fossils, so characteristic of the Cretaceous rocks above, and of the Oolitic strata below, and to the presence in the Weald of Paludinæ, Melaniæ, Cyrenæ, and various fluviatile shells, as well as the bones of terrestrial reptiles and the trunks and leaves of land-plants.