4 
“3 
3 
846 STRATIGRAPHICAL GEOLOGY. [Boor VI. 
zones, the uppermost of which contains the greater part of the terres- 
trial vegetation, and also most of the fish and reptilian remains. The 
fossils are mainly marine mollusca, which, taken in connection with the 
flora, indicate that the climate was somewhat tropical in character. The 
plants include the fruits or seeds of the following, among other genera : 
Pinus, Callitris, Salisburia ; Musa, Sabal, Elais, Nipadites, Iriartea, Livis- 
tona, Cinocarpus ; Quercus, Liquidambar, Nyssa, Diospyros, Symplocos, 
Magnolia, Juglans, Eucalyptus, Amygdalus, Bankinia.*’ Crustacea abound 
(Xanthopsis, Hoploparia). Gasteropods are the prevalent molluscs, the 
common genera being Pleurotoma (45 species), Fusus (15 species), Cypreea, 
Murex, Cassidaria, Pyrula, and Voluta. The cephalopods are represented 
by 6 or more species of Nautilus, by Belosepia sepioidea, and Beloptera 
Levesquei. Nearly 100 species of fishes occur in this formation, the rays 
(Myliobates, 14 species) and sharks (Lamna, Otodus, &c.) being specially 
numerous. A sword fish (Tetrapterus priscus), and a saw-fish (Pristis 
bisulcatus) about 10 feet long, have been described by Agassiz from the 
London Clay of Sheppey, whence almost the whole of the fish remains 
have been obtained. The reptiles were numerous, but markedly unlike, 
as a whole, to those of Secondary times. Among them are numerous 
turtles and tortoises (Chelone 10 species, Trionyx 1 species, Platemys 6 
species), two species of crocodile, and a sea-snake (Palzophis toliapicus), 
estimated to have equalled in size a living Boa constrictor. Remains of. 
birds have also been met with (Lithornis vulturinus, Halcyornis toliapicus, 
Dasornis londinensis, Odontopteryx toliapicus, Argillornis longipennis, Enali- 
ornis). The mammals numbered among their species a hog (Hyracotherium), 
several tapirs (Coryphodon, &c.), an opossum (Didelphys), and a bat. The 
carcases of these animals must have been borne seawards by the great 
river which transported so much of the vegetation of the neighbouring 
land. 
Middle.—In the London basin this division consists chiefly of sands, 
which are comprised in the two groups of the lower and middle “ Bag- 
shot beds.” ‘the lower of these two groups, consisting of yellow 
siliceous, unfossiliferous sands, with irregular ight clayey beds, attains 
a thickness of about 100 to 150 feet. The second group, or “ Middle 
Bagshot beds,” is made up of sands and clays, sometimes 50 or 60 feet 
thick, containing few organic remains, among which are bones of turtles 
and sharks, with a few molluscs (Cardita acuticostata, C. elegans, C. plani- 
costa, C. imbricata, Corbula gallica, C. striata, Ostrea flabellula). In the 
Hampshire basin the Lower Bagshot beds attain a much greater develop- 
ment, being not less than 660 feet thick in the Isle of Wight, where they 
consist of variously coloured unfossiliferous sands and clays, with minor 
beds of ironstone and plant-bearing clays. On the mainland at Studland, 
Poole, and Bournemouth, the same beds appear. The Middle Bagshot 
beds are represented in the Hampshire basin by an important series of 
clays, marls, sands, and lignites upwards of 100 feet thick, known as the 
Bracklesham beds, from their occurrence at Bracklesham, on the coast of 
Sussex. J rom these strata a large series of marine organisms has been 
obtained, among which are Belosepia sepioidea, B. Cuvieri, Cypreea inflata, 
C. tuberculosa, Marginella eburnea, M. ovulata, Voluta crenulata, V. spinosa, 
V. angusta, V. Branderi, V. cythara, V. muricina, Mitra labratula, Conus 
1 Ettingshausen and Gardner, “ British Eocene Flora,” Palwontograph. Soe. p. 12. 
