i 3 o An ACCOUNT of 



glafs : But the mod 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 compact, 

 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 connected 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 j for 

 the angles of the fragments were as fharply defined as if newly 

 feparated from their refpeclive original beds. 



The rocks from whence thefe different mafTes 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 ftrata 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. 



The 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 fprings 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 



