BF 
Geology of Antigua. SL 
are found only in rocks of the chert family, which is a very im- 
portant circumstance in ascertaining the origin of the beds. 
As I have already intimated, the two preceding formations 
abound in the silicious fossils of an exceedi ly interesting and 
important character. For variety of structtire, for fineness and 
beauty of material, and for richness of color, I know of none in 
any part of the world in comparison with which they would 
suffer. They are found in the form of jasper, cornelian, agate, 
chalcedony—sometimes existing separately, at others all beauti- 
fully blended in the same specimen. The coloring matter also 
Varies in intensity, presenting every tint and shade which are pe- 
culiar to those minerals. But the most. striking feature of all, 
is the perfect preservation of the form and structure of the petri- 
' fied substances, even of such as in a living state are most delicate. 
For example, the opening leaves of the banana, than which no 
vegetable fibre can be more tender, have been converted into 
silex and perfectly preserved. I saw myself the petrified pod of 
a tamarind, so entire in its anape and all its parts, that no one 
could mistake it... 
These fossils may conveniently be divided ‘into two classes— 
aa marine and the land fossils. 'The former consist of corals, 
shells, &c., which are found principally in the calcareous iain 
tion, and are particularly abundant and beautiful in Belfast Divis-. 
ion. ‘They frequently appear on the surface, but are often found — 
at considerable depths. 'The corals are Srecuacinthy very striking ; 
they are converted into chalcedony both pure and colored, but 
still retaining their pattern so perfectly, that the genus may be 
recognized when they are set ina breastpin. All the fossils in 
the calcareous formation are,by no means of this’ character. 
Many | of. them are cealeareous. The silicious prevail only in 
But ine. most rere ee ee, fossils is the Blintted wood— 
the ordinary trees and shrubs of the climate still retaining their 
individual structures, but converted into the choicest mineral sub- 
stances. Fossils of this class are confined to the chert and clay 
formations, 'They are generally found intermingled with the 
chert in broken fragments, and scattered over the surface of the 
earth. Sometimes i in low districts, they constitute immense beds, 
and give one the idea of a thick forest, which has been prostra- 
ted by some mighty owe Pare into silex, and buried be- 
Vout. XX XV.—No. 
