Occasional Notes. 331 
elevated portions most markedly so ; while large areas 
of the sward-like levels were perfeftly desiccated. The 
water in the various channels was very shallow, and the 
deep basins or depressions contained but very small 
quantities, though in no case was any found to be quite 
dry. Frequently the surface of the water in these shallow 
basins was more or less covered with a green, apparently 
a confervoid, layer. In these pools at the bottom of these 
wide basins, Mr. DRESSEL found a considerable quantity 
of quartz, in the form both of separate crystals, and of 
aggregated masses, of various and often of large sizes. 
The presence of such quartz in such positions and 
under such conditions, is an extremely interesting fa6l, 
though our want of knowledge of the petrographic 
chara6ler of the formation on the top of Roraima beyond 
the fa6l of its being sandstone, renders it barren and one 
hardly justifying speculation. 
It will be remembered that on the first ascent, no 
animal life was noticed during the short time spent on 
the top ; and this necessarily denoted the likelihood of the 
absence or great rarity of birds and inserts, which are, 
so to speak, the only two obtrusive forms of animal life. 
During the two or three hours, spent on the top by Mr. 
DRESSEL, no birds were seen ; but a few specimens 
of butterflies, all of one kind, and of a dark-brown 
and nearly black colour, were observed, and two 
of them caught, though, unfortunately, owing to 
the difficulty of keeping them until arrival in town, 
one alone was sufficiently preserved to shew much 
of its strufture. In the shallow basins a few forms 
of a small black toad with a yellow spot on the throat, 
were also seen, and one was caught ; but, being left in a 
