^oa Oti the Natural Hj/lory of Guiana. 



There are of them further down in the coutitry, but not clofe to the river fide. This one- 

 is the extremity of a ridge which extends to the weft ward feveral miles. As you aicen^ 

 the river you meet with many more of the fame kind on both fides, whofe direction feems 

 likewife to be eaft and weft, or nearly at right angles with the average courfe of the ftream. 

 They vary from 50 to ico, 150 or 200 feet of perpendicular height above the level of the 

 river and the intervening flat country. Their breadth and extent vary fometimes only a 

 few hundred paces, fometimes many miles. Their length is great ; with fome interrup- 

 tions, 1 have reafon to believe they are generally continued from one fide of the colony to 

 the other, only interfered in different places by the rivers and their branches. They confill 

 of a pure filiceousfand, fo white that it da-^zles the eyes, commonly fine-grained and loofe, 

 but not unfrequently mixed with littlt; ftrata of coarfer pebbles, mofily quartz, and fome- 

 times concreted into a proper fand-flone. In the laft cafe, a black or rcddifh" tinge is in 

 many cafes communicated to it from clay, decayed vegetables, or other extraneous matter. 

 There is no regular ftratification to be found in it, more than what is common to all funds 

 the produce of depofitions oftiifferent dates; and, as they are of different materials, thicker 

 in one place, thinner in another, fometimes horizontal but oftener inclined, and convex 

 or concave according to circumftances. We could meet with no appearance of (hells or 

 other marine produftions, but in a few places pieces of broken vegetables buried in the 

 fand where it was concreted. They were black, as all the foffil vegetables that I have ever 

 feen in (\md-ftone. Upon and by the fides of the fand-hills grows the moft valuable timber 

 of thefe colonies. The trees there are of a good fize, and very clear of obllruding under- 

 woods or vines. The wallabba (parivoa grandiflora of Aublet) ; the fipiri or green-heart 

 (a new fpeciesof laurel); the coumarou or tonqusebean tree, coumarouna odorata of 

 Aublet ; the mora, valuable for boat timbers ; and many others whofe wood is equally hard 

 and beautiful. 



Continuing to afcend the river, the fand-hills become rather more frequent i but the in- 

 tervals ftill remain a perfeifl flat, though now feveral feet above the level of the ftream, 

 and the foil is ftill a ftiff clay. Hitherto the river is deep all over, generally from two to fiv« 

 fathoms ; the bottom is mud or clay, and the (hores on either fide at low water covered 

 with ooze. About 1 30 miles up, however, or juft before it begins to fliallow, the bottom 

 is covered with banks of a hard white or brown fand. It was a problem for fome time, 

 whence all this fand originated in fuch a country. It was foon folved. Leaving here the 

 veflel that had hitherto carried us, we proceeded in a canoe ; and at about 160 or 170 

 miles diftance from the mouth of the river we met with the firft proper hills of folid mate- 

 rials. The neareft to us was a rock of granite pvojed"ling into the ftream, whofe dire£lion 

 it gave a change to at this place ; and it ferved for a landing place to the higheft piece of 

 cleared land upon the river not to the poft-holders. It was part of a low ridge of the 

 fame flone which croffed the country probably to Berbia or beyond it, and was fucceeded 

 by many other feries of hills more inland, and, as far as we could examine them, of the fame 

 materials. The granite was both of the red and the gray kinds, but chiefl^y of the latter. 

 A number of feams or dikes crofl'ed it here and there in all direi^ions, not diftincflly feparate,, 

 but firmly united to the reft, making as it were but one body with it, and confifting of the 

 fame materials differently modified. Their component parts were generally fmaller; they 

 were more compaft and clofer in the texture than what furrounded them ; and where they 



had 



