and Volcanic Substances. 219 
islands ; as every current of lava that runs into the sea, is 
liable to be covered with corals madropores, &c. and again 
covered with Lava, until it comes above the surface of the 
sea. 
St. Eustatia Ib. on the South East side of the large hill 
towards St.. Christopher, there is a stratification of madre- 
pore Limestone alternating with beds of shells similar to 
those found at present in the sea. ‘The whole of this ma- 
rine deposition dips to the South West at an angle of up- 
wards of 45° from the horizon, resting upon a bed of cin- 
ders, full of pumice and other volcanic rocks ; and is imme- 
diately covered by a bed of Madrepores, sand and cinders 
mixed together with blocks of volcanic rocks, so dissemina- 
ted that there can be no doubt of the volcanic origin of the 
substance above and below the madrepore rock, which may 
be from fiye to six hundred yards thick. 
Saba. p. 148. The madrepore and coral rocks mixed 
with shells, partly similar to those at present found in the 
sea, alternate with the cinders and other volcanic rocks, 
presenting much the appearance of the whole having been 
ejected from the bottom of the ocean. 
_ He concludes, that all these islands were probably thrown. 
up-from the bottom of the ocean, and that the seat of com- 
bustion was in the primitive, because the transition formed 
the islands of the Eastern group. Great attention is due to 
the opinions of this very experienced Geologist. That 
Islands should be thus raised is so common that without 
voyaging to those of the Eastern Archipelago, we may refer 
to the eleven mentioned by Pliny, to the following noticed . 
by’Forber 127. Ischia, Nistia, Santorini: Monte Nuovo, 
Monte Gauro or Barbaro, Monte di Camaldoni, St. Elmo, 
Capo di Chino, Pizzo-Falcone, (the ancient Echia,) Ib. 
Attempts have been made to ascertain the ages of different 
volcanic eruptions, from the quantity of soil formed upon 
them; but this is manifestly an inaccurate mode of compu- 
tation, owing to the very different states of fusion in which 
Lavas have been ejected, and the, different kinds of stones 
of which they are composed. Count Borch has observed 
that in December, 1776, the Lava of tna poured out in 
1157, had a coating of twelve inches of earth. 1 Spal. tr. 
p. 205. i 
