Fresh-water Deposits.—Insect-beds.—From the above remarks the reader will infer that the Lias is for the most part a marine deposit. Some members, however, of the series have an estuarine character, and must have been formed within the influence of rivers. At the base of the Upper and Lower Lias respectively, insect-beds appear to be almost everywhere present throughout the Midland and South-western districts of England. These beds are crowded with the remains of insects, small fish, and crustaceans, with occasional marine shells. One band in Gloucestershire, rarely exceeding a foot in thickness, has been named the “insect limestone.” It passes upward, says the Reverend P. B. Brodie,[11] into a shale containing _Cypris_ and _ Estheria,_ and is full of the wing-cases of several genera of Coleoptera, with some nearly entire beetles, of which the eyes are preserved. The nervures of the wings of neuropterous insects (Figure 382) are beautifully perfect in this bed. Ferns, with Cycads and leaves of monocotyledonous plants, and some apparently brackish and fresh-water shells, accompany the insects in several places, while in others marine shells predominate, the fossils varying apparently as we examine the bed nearer or farther from the ancient land, or the source whence the fresh water was derived. After studying 300 specimens of these insects from the Lias, Mr. Westwood declares that they comprise both wood-eating and herb-devouring beetles, of the Linnean genera _Elater, Carabus,_ etc., besides grasshoppers (_Gryllus_), and detached wings of dragon-flies and may-flies, or insects referable to the Linnean genera _Libellula, Ephemera, Hemerobius,_ and _Panorpa,_ in all belonging to no less than twenty-four families. The size of the species is usually small, and such as taken alone would imply a temperate climate; but many of the associated organic remains of other classes must lead to a different conclusion. Fossil Plants.—Among the vegetable remains of the Lias, several species of _Zamia_ have been found at Lyme Regis, and the remains of coniferous plants at Whitby. M. Ad. Brongniart enumerates forty-seven liassic acrogens, most of them ferns; and fifty gymnosperms, of which thirty-nine are cycads, and eleven conifers. Among the cycads the predominance of _ Zamites,_ and among the ferns the numerous genera with leaves having reticulated veins (as in Fig. 349), are mentioned as botanical characteristics of this era.[12] The absence as yet from the Lias and Oolite of all signs of dicotyledonous angiosperms is worthy of notice. The leaves of such plants are frequent in tertiary strata, and occur in the Cretaceous, though less plentifully (see p. 303). The angiosperms seem, therefore, to have been at the least comparatively rare in these older secondary periods, when more space was occupied by the Cycads and Conifers.