130 An ACCOUNT of 
glafs: But the moft curious confifted of an heterogeneous mix- 
ture of various fubftances, cemented indifcriminately together 
by fome operation, fubfequent to their original formation, and 
fo ftrongly, that the rock was broken with difficulty by our 
hammers. It-confifted of pieces of black glafs, (a lava in all 
probability much vitrified), and large pieces of a clofe, gray 
lava, the cavities and pores of which were filled with zeolites 
finely radiated. Some pieces of black lava, in parts compa¢t,. 
and in other parts fo porous as to approach nearly to a pumice 
ftone, were mixed with the reft of the mafs. A mixture of 
thefe fame fubftances, (the lavas, the glafs and the zeolites), 
pounded in fmall grains, filled the fpaces between the larger 
pieces, and conneéted the whole into a folid rock. The heat 
(if heat it was) which had cemented thefe materials, had not 
been ftrong enough to reduce any one to a ftate of fufion; for 
the angles of the fragments were as fharply defined as if newly: 
feparated from their refpective original beds. 
Tue rocks from whence thefe different maffes have been de-- 
tached, lay heaped together in fo disjointed and irregular a. 
manner, that fome violent convulfion has evidently taken place 
among them fince their firft formation ; but fimilar appearances: 
of diforder are to be feen in every range of hills in the country. 
Regular {trata are no where to be met with. It appears as if all 
this part of the ifland, at different periods, had been thrown up. 
from its foundations. 
TueE valley is in this place fertile, and nearly half a mile in 
breadth. It becomes more narrow towards the north; and it 
is there rendered barren by heaps of crumbled lava, or other 
rubbifh, brought down from the hills by the waters. Thefe 
have the appearance of artificial mounds, and a great number 
of f{prings are continually boiling through them. Below the 
furface, a general decompofition feems taking place; for almoft 
wherever the ground is turned up, a ftrong heat is felt, and the 
loofe earth and ftones are changing gradually into a clay or bole 
. | of 
