DISTRIBUTION OF THE MOLLUSCA IN TIME. 133 
The peculiar physical conditions of the Chalk period are 
represented at the present day, not so much by the Coral Sea, 
as by the Xgean, where calcareous mud, derived from the waste 
of the scaglia regions, is being rapidly deposited in deep water. 
(Forbes. ) 
The Wealden period was styled the ‘‘ Age of Reptiles” by Dr. 
Mantell, who compared the state of England at that time with 
the present condition of the Galapagos Islands. 
The Oolitic period finds its parallel in Australia, as long since 
pointed out by Professor Phillips, and the comparison holds 
good to some extent, both for the Marine and Terrestrial 
Faunas. 
The Trias, with its foot-prints of gigantic wingless birds, has 
been compared with the state of the Mascarene Islands only a 
few centuries ago, and with the New Zealand Fauna, where 
birds are still the highest aboriginal inhabitants.* 
Paleeozoic Age.—It has lately been shown by Professor Ramsay 
that signs of glacial action may be traced in some of the trappean 
conglomerates of the Permian and of the Devonian or Old Red 
Sandstone period in England ; and Mr. Page has endeavoured 
to apply the same interpretation to phenomena of a similar cha- 
racter in the Old Red sandstone of Scotland.+ Geologists gene- 
rally have abandoned the notion, once very prevalent, of a 
universal high temperature in the earliest periods; a notion 
which they had derived from the occurrence of certain fossil 
plants, corals, and shells in high latitudes. 
The absence of remains of mammalia in the paleeozoic forma- 
tions, is at present a remarkable fact, but it is completely 
paralleled in the great modern zoological province of the Pacific 
Islands. 
Baron Humboldt has speculated on the possibility of some land 
being yet discovered, where gigantic lichens and arborescent 
mosses may be the princes of the vegetable kingdom.{ If such 
exist, to shadow the Paleeozoic age, its appropriate inhabitants 
would be like the cayern-haunting Proteus, and the Silures 
which find an asylum eyen in the craters of the Andes. 
What, then, is it which has chiefly determined the character 
of the present zoological provinces? What law, more powerful 
than climate, more influential than soil, and food, and shelter ; 
* Tn a paper read before the British Association, on the subject of the great extinct 
wingless birds of New Zealand, Professor Owen suggested the notion of land having 
been propagated like a wave throughout the vast interval between Connecticut and N>w 
Zealand, since the Triassic period. 
T See also the Rey. J. G. Cumming’s “Isle of Man” (1849), p. 89. 
t Views of Nature, p. 221. Bohn’s ed. 
