534 PHILOSOPHICAL TRANSACTIONS. [aNNO I/SQ. 



ance of being formed by convulsions of nature from subterraneous fires. In 

 several parts of the woods are hot springs; some he tried, with a well graduated 

 thermometer of Fahrenheit, were 20° and 11^ hotter than the atmosphere at 

 the time of trial. From its position to them, this part of the island has cer- 

 tainly experienced the effects of the volcanic eruptions, which have heaped 

 up those prodigious masses of mountains that terminate the province of Paria 

 on the north; and no doubt there has been, and still probably is, a communica- 

 tion between them. One of these mountains opposite to La Bray in Trinidad, 

 about 30 miles distant, has every appearance of a volcanic mountain : however, 

 the volcanic efforts have been very weak here, as no trace of them extend above 

 2 miles from the sea in this part of the island, and the greater part of it has had 

 its origin from a very different cause to that of volcanos; but they have certainly 

 laid the foundation of it, as is evident from the high ridge of mountains which 

 surrounds its windward side to protect it from the depredations of the ocean, and 

 is its only barrier against that over-powering element, and may properly be 

 called the skeleton of the island. 



From every examination Mr. A. has made, he finds the whole island formed 

 of an argillaceous earth, either in its primitive state, or under its different meta- 

 morphoses. The bases of the mountains are composed of schistus argillaceus* 

 and talcum lithomargo; but the plains or low-lands remaining nearly in the same 

 moist state as at its formation, the component particles have not experienced the 

 vicissitudes of nature so much as the more elevated parts, consequently retain 

 more of their primitive forms and properties. As argillaceous earth is formed 

 from the sediment of the ocean, from the situation of Trinidad to the continent, 

 its formation is easily accounted for, granting first the formation of the ridge of 

 mountains that bound its windward side, and the high mountains on the conti- 

 nent that nearly join it : for the great influx of currents into the Gulf of Paria, 

 from the coasts of Brazil and Andalusia, must bring a vast quantity of light 

 earthy particles from the mouths of the numerous large rivers which traverse 

 these parts of the continent; but the currents being repelled by these ridges of 

 mountains, eddies and smooth water will be produced where they meet and 

 oppose, and therefore the earthy particles would subside, and form banks of 

 mud, and by fresh accumulations added would soon form dry land; and from 

 these causes it is evident such a tract of country as Trinidad must be formed. 

 But these causes still exist, and the effect from them is evident; for the island is 

 daily increasing on the leeward side, as may be seen from the mud-beds that 

 extend a great way into the Gulf, and there constantly increase. But from the 

 great influx from the ocean at the south end of the island, and its egress to the 

 Atlantic again, through the Bocas, a channel must ever exist between the conti- 

 nent and Trinidad. 



