150 Dr. Correa de Serra on a submarine Forest , 
almost in the same level, and that level generally under the 
common mark of low water, must naturally strike the observer, 
and give birth to the following questions. 
1. What is the epoch of this destruction ? 
2. By what agency was it effected ? 
In answer to these questions, I will venture to submit the 
following reflections. 
The fossil remains of vegetables hitherto dug up in so many 
parts of the globe, are, on a close inspection, found to belong 
to two very different states of our planet. The parts of vege- 
tables, and their impressions, found in mountains of a cota- 
ceous, schistous, or even sometimes of a calcareous nature, are 
chiefly of plants now existing between the tropics, which 
could neither have grown in the latitudes in which they are 
dug up, nor have been carried and deposited there by any of the 
acting forces under the present constitution of nature. The 
formation, indeed, of the very mountains in which they are 
buried, and the nature and disposition of the materials which 
compose them, are such as we cannot account for by any of 
the actions and re-actions which, in the actual state of things, 
take place on the surface of the earth. We must necessarily 
recur to that period in the history of our planet, when the sur- 
face of the ocean was at least so much above its present level, 
as to cover even the summits of these secondary mountains 
which contain the remains of tropical plants. The changes 
which these vegetables have suffered in their substance, is 
almost total ; they commonly retain only the external configu- 
ration of what they originally were. Such is the state in which 
they have been found in England, by Llwyd; in France, by 
Jussieu; in the Netherlands, by Burtin; not to mention in- 
