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MOUNT RORAIMA IN BRITISH GUIANA, 5 
Appearance and Structure of Roraima, and its Geographical Relations to the Moun- 
tain-systems of South America.—Im Thurn and Perkins, who made the first ascent on 
December 18, 1884, reached the top under unfavourable conditions: they had ascended 
that day from their base-camp at 5400 feet, and only reached the summit in the 
afternoon, when clouds almost invariably envelop it; they had no means of remaining 
there, and were forced to return after a very short stay of three hours, Perkins speaks 
of these clouds as impenetrable (Proc. Roy. Geogr. Soe. vii. 1885, p. 532) *; at all 
events they limited the range of exploration, and the report was made that * the 
vegetation on the summit is extremely scanty and insignificant, there being no trees, 
only small bushes from three to six feet in height, growing at long intervals." It has 
been reserved for McConnell and Qmueleh to ascertain that there exist in favoured 
places trees which attain a height of no less than forty feet. 
Of the ascents of Dressel and Kromer I can glean no more than is in a brief notice in 
‘Timehri,’ 1887, p. 330. Neither can have remained on the summit for more than a few 
hours. 
The features of this summit are :—Blackened elevated ridges, irregularly terraced and 
rugged; winding gullies which drain away the superabundant rain through shallow 
pools; patches of sand in their shelter with isolated small bushes; clumps of vegetation 
lodged in the most protected spots; piles of wind-cut rocks without a sign of plant-life, 
rising into pinnacles; no soil; the keen northerly wind, and mists which gather at least 
after noon on almost every day in the whole year. The highest pinnacle rises to 
8740 feet; the deepest gully may be 400 feet below it. 
. The known sides of the mountain which face north-east aud south-easi, produce rocky 
savannah up to 5000 or 5100 feet, the rocks so numerous that Appun likens the country 
to a grave-yard ; then forest to 7100 feet, dense below but stunted and more open above ; 
and from this altitude rise the precipitous cliffs, which give to the whole the appearance 
of a vast fortress with a tree-clad glacis slope. 
These precipices were deemed impossible of ascent by the travellers they had baffled 
until Whitely indicated, and im Thurn showed practicable, the one known ledge leading 
to the summit. 
The rock is a quartzose sandstone interbedded with diorite. The topmost and thickest 
bed of diorite comes to the surface where the dense forest is; the lower beds make a 
series of terraces down the lower slopes. These beds lie perfectly horizontal without 
folding or other sign of any great disturbance.  Diorite lends itself to the formation of a 
soil t, the sandstone does not. | 
Such sandstones as constitute Roraima have a very wide extension in South America ; 
they pass eastward into Surinam; Duida is made of them; they form the bed-rock of 
the llanos of Venezuela, and appear in the Caripe mountains to the east of Caracas ; 
in Brazil the area oceupied by them is immense. 
` * Of, im Thurn in * Timehri,’ 1885, p. 41. 
` + The Indians prepare their provision-grounds on the diorite (see Brown E Sawkius, Reports, p. 17), aud those 
living under the south-eastern face of Roraima have placed them far up the sister-mountain of Kukenaam, where 
the diorite comes to the surface (Quelch, in * Timehri, 1895, p. 164). 
B2 
