CYCADEAN PLANTS. 
107 
Stonesfield and Solenhofen deposits, as well 
, as that of Mamers in France, throw the 
I chief light by its contents on the plants of 
1 this period; as the circumstances of deposit 
i in these instances have been evidently very 
I favourable to the preservation of organic 
: structure. 
At the two former places are found sea- 
»weed, which accords with the neighbouring 
! incontestible evidence of coral reefs, to shew^ 
I the existence of the ancient seas of these 
i their tropical islands, for even the sea weed is 
I of an equatorial character. Several ferns 
i too occur in the same locality, but the pre- 
r dominant race is that of the Cycadeae. 
! These palmy and tropical plants which now 
I form so very inconsiderable a portion of the 
£ existing vegetation, (not perhaps equalling 
Ea thousandth part of it,) in the days of the 
! Oolite deposit constituted more than half of 
:the entire vegetable kingdom. At Stones. 
:field, in the dried mud of the Oolite deposit, 
:are also found remains of several species of 
'.unknown cone-bearing plants. 
The lowest members of the series appear 
to be Lias and Lias Marl. In’ this deposit 
