THE VOYAGE OF THE BEAGLE 511 



recent streams of lava, is of an oval shape, thirteen geo- 

 graphical miles across, in the line of its shorter axis. The 

 exterior bounding mountains come into that class of struc- 

 tures called Craters of Elevation, which are supposed to have 

 been formed not like ordinary craters, but by a great and 

 sudden upheaval. There appears to me to be insuperable 

 objections to this view: on the other hand, I can hardly 

 believe, in this and in some other cases, that these marginal 

 crateriform mountains are merely the basal remnants of 

 immense volcanos, of which the summits either have been 

 blown off, or swallowed up in subterranean abysses. 



From our elevated position we enjoyed an excellent view 

 over the island. The country on this side appears pretty well 

 cultivated, being divided into fields and studded with farm- 

 houses. I was, however, assured that of the whole land, not 

 more than half is yet in a productive state; if such be the 

 case, considering the present large export of sugar, this 

 island, at some future period when thickly peopled, will be 

 of great value. Since England has taken possession of it, a 

 period of only twenty-five years, the export of sugar is said 

 to have increased seventy-five fold. One great cause of its 

 prosperity is the excellent state of the roads. In the neigh- 

 bouring Isle of Bourbon, which remains under the French 

 government, the roads are still in the same miserable state 

 as they were here only a few years ago. Although the 

 French residents must have largely profited by the increased 

 prosperity of their island, yet the English government is far 

 from popular. 



yd. In the evening Captain Lloyd, the Surveyor-general, 

 so well known from his examination of the Isthmus of Pana- 

 ma, invited Mr. Stokes and myself to his country-house, 

 which is situated on the edge of Wilheim Plains, and about 

 six miles from the Port. We stayed at this delightful place 

 two days ; standing nearly 800 feet above the sea, the air was 

 cool and fresh, and on every side there were delightful walks. 

 Close by, a grand ravine has been worn to a depth of about 

 500 feet through the slightly inclined streams of lava, which 

 have flowed from the central platform. 



^Captain Lloyd took us to the Riviere Noire, which is 

 several miles to the southward, that I might examine some 



