206 THE MEDALS OF OREATION. Cuap. VI. — 
Xylophagous mollusks are found in the petrified and car- — 
bonized wood. Fresh-water Desmidiaceze, and a few marine ~ 
remains, are associated with this fossil flora, which is distin- 
guished by the abundance of Ferns and dicotyledonous leaves, 
and the scarcity of Cycads; among them are undoubted — 
Proteacee. 
The specimens collected by M. Debey from the lower creta- — 
ceous beds are the following : 
Algz, 15. Filices, 28. Hydropteride, 2. Cycadee, 5. 
Naiadez, 5. Palme, 1. Conifers, 20. Juliflore, 5. Cred- 
neriz, 3. Leaves of Dicotyledons, undetermined, 26. Fruits 
undetermined, 8. Woods.* 
This assemblage of angiosperms, with gymnosperms, and 
cryptogamia, at the commencement of the Cretaceous epoch, — 
when the Iguanodon and other reptilian forms of the 
Oolite and Wealden still inhabited the land and water, — 
proves, as Sir Charles Lyell has remarked,t that the mete-— 
orological phenomena of that remote period differed in no 
essential particular from those which now prevail. 
RETROSPECT OF FOSSIL BOTANY. 
Ir we pass from the consideration of details of structure, 
and of botanical affinities, to a general survey of the 
mineralized remains of the vegetable kingdom, we perceive 
that from the paleeozoic deposits, to those which are con- 
temporaneous with the human race,— from the coal-measures 
to the peat bogs of modern times,—vast accumulations of 
vegetable matter, in various states of carbonization, have 
been produced from the imbedded relics of the terrestrial 
floras that flourished during the respective periods of their 
formation ; petrifaction, or the transmutation of vegetable — 
* Geol. Journal, vol. vii. p. 111. 
+ Supplement to the New Edition of Elements of Geology, 1852, 
D.XY. 
