On the opposite page an ideal landscape of the period (PLATE XX.) represents some of the features of the Upper Oolite, especially the vegetation of the Jurassic period. The _Sphenophyllum_, among the Tree-ferns, is predominant in this vegetation; some _Pandanas_, a few _Zamites_, and many _Conifers_, but we perceive no Palms. A coral islet rises out of the sea, having somewhat of the form of the _atolls_ of Oceania, indicating the importance these formations assumed in the Jurassic period. The animals represented are the _Crocodileimus_ of Jourdan, the _Ramphorynchus_, with the imprints which characterise its footsteps, and some of the invertebrated animals of the period, as the _Asteria_, _Comatula_, _Hemicidaris_, _Pteroceras_. Aloft in the air floats the bird of Solenhofen, the _Archæopteryx_, which has been re-constructed from the skeleton, with the exception of the head, which remains undiscovered. * * * * * The rocks which represent the Upper Oolite are usually divided into two series: 1. The _Purbeck Beds_; 2. The _Portland Stone and Sand_; and 3. The _Kimeridge Clay_. The _Kimeridge Clay_, which in many respects bears a remarkable resemblance to the Oxford Clay, is composed of blue or yellowish argillaceous beds, which occur in the state of clay and shale (containing locally beds of bituminous schist, sometimes forming a sort of earthy impure coal), and several hundred feet in thickness. These beds are well developed at Kimeridge, in Dorsetshire, whence the clay takes its name. In some parts of Wiltshire the beds of bituminous matter have a shaly appearance, but there is an absence of the impressions of plants which usually accompany the bitumen, derived from the decomposition of plants. These rocks, with their characteristic fossils, _Cardium striatulum_ and _Ostrea deltoidea_, are found throughout England: in France, at Tonnerre, Dept. Yonne; at Havre; at Honfleur; at Mauvage; in the department of the Meuse it is so rich in shells of _Ostrea deltoidea_ and _O. virgula_, that, “near Clermont in Argonne, a few leagues from St. Menehould,” says Lyell,[70] “where these indurated marls crop out from beneath the Gault, I have seen them (_Gryphæa virgula_) on decomposing leave the surface of every ploughed field literally strewed over with this fossil oyster.” [70] “Elements of Geology,” p. 393. The second section of this series consists of the oolitic limestone of Portland, which is quarried in the Isle of Portland and in the cliffs of the Isle of Purbeck in Dorsetshire, and also at Chilmark in the Vale of Wardour, in Wiltshire. In France, the Portland beds are found near Boulogne, at Cirey-le-Château, Auxerre, and Gray (Haute Saône).