772 STRATIGRAPHICAL GEOLOGY. — [Boox VI 
World we find it presenting still another aspect in North-Western — 
India, while in America the meagre representatives of the European ~ 
development have again a facies of their own. Hence no generally — 
applicable petrographical characters can be assigned to this part 
of the geological record. | 
The flora of the Jurassic period, so far as known to us, was 
essentially gymnospermous. The Paleozoic forms of vegetation 
traceable up to the close of the Permian system are here entirely 
absent. Equisetums, so common in the Trias, are still abundant, one 
of them (H. arenacewm) attaining gigantic proportions. Ferns like- 
wise continue plentiful, some of the chief genera being Alethopteris, 
Sphenopteris, Phlebopteris, and Oleandridiwm (Teniopteris). The 
Cycads, however, are the dominant forms, in species of Zamites, 


Fic. 364.—Jurassic Cycaps (Lower Oolite). 
a, Williamsonia (Zamia) gigas (Carr) (3); b, Cycadites lanceolata (Lindl. and Hutt.) 
(3); ¢, Cycadites (Pterophyllum) pectinoides (Phill.) (nat. and mag.). 
Pterophyllum, Anomozamites, Pterozamites, Dioonites, Podozamites, 
Sphenozamites, Glossozamites, Otozamites, Cycadites, Olathraria, Cyca- 
doidea, Zamiostrobus, Beania, Cycadospadix, Cycadinocarpus. Conifers 
also are found in some numbers, particularly Araucarians of the 
genera Pachyphyllum and Araucaria, also Pinites, Brachyphyllum, 
and Thuyites. 
The Jurassic fauna presents a far more varied aspect than that 
of any of the preceding systems. Owing to the intercalation of 
numerous fresh-water, and sometimes even terrestrial, deposits 
among the marine formations, traces of the life of the lakes and 
rivers, as well as of the land itself, have been to some extent 
embalmed, besides the preponderant marine forms. The conditions 
of sedimentation have likewise been favourable for the preservation 
of a succession of varied phases of marine life. Professor Phillips 
