324 
SIR RODERICK I. MURCHISON’S ADDRESS. [May 24, 1858. 
probably, is a vast trough or basin, encircled on all sides by higher 
ridges.* It will be recollected how I then showed, that these ridges, 
wherever we had certain knowledge of them, consisted of primeval 
or palaeozoic rock, for the most part crystalline — that they enclosed 
fresh- water deposits of younger age, and lacustrine character ; and, 
therefore, that the main physical features of modern Africa, such 
as I have described them to be, are those which have continued 
to characterise that continent from the earlier geological epochs 
down to the present day. 
My hearers will also recollect that, justified by the discoveries 
of Livingstone, I took occasion, at our last Anniversary, to throw 
great doubts on the existence of snow-capped mountains in these 
equatorial latitudes. As far as they have gone, the observations of 
Burton’s party throw no new light on that hypothesis ; and it still 
remains to be determined whether or no the Nile, like the Zambesi, 
Congo, and Niger, has its chief sources in the great watery interior 
plateau. ( See Ann. Address, 1857, p. clxx.)j 
* See also Dr. Livingstone’s Cambridge Lectures, with a Prefatory Letter by Professor 
Sedgwick. Edited by the Rev. Wm. Monk, &c. ; with map by Arrowsmith, granted 
especially by the President and Council of the Royal Geographical Society. 
f Whilst these pages are passing through the press, accounts have been received inform- 
ing us that Captains Burton and Speke had penetrated westwards to near 500 miles 
from the coast, according to their dead reckoning. They had passed from the Ugogo 
country, through the Mkali Mgumbu wilderness, had crossed the frontier of the Waniemesi, 
and they wrote from a place, Unianembe, 70 miles beyond it. The boundaries of the 
different tribes, and the physical features of the country, so far as our travellers have gone, 
correspond very closely to the description given of them by the Rev. Mr. Erhardt, who 
drew his information entirely from native testimony. It will be recollected, that a short 
account of his memoir, and an accompanying sketch map, were published in the first number 
of our Proceedings, and, if reference be made to the latter, the point on the line of route 
whence we have received our latest intelligence will be found to be that which is intersected 
by the 34th parallel of longitude. Capt, Speke places the real position of the station in 
question in lat. 5° 2', and considerably to the westward of that point. The doubts which 
I ventured to throw out in the Address of last year, respecting the .existence of lofty snow- 
covered. African mountains under the Equator whence the Nile flows, and the theoretical 
view (founded on the observations of Livingstone) which was then propounded, of the, origin 
of great periodical floods by the bursting and overflow of large marshy tracts of Central 
Africa, might, at first sight, seem to receive some confirmation from the researches and 
writings of the ancien‘s. My accomplished friend Sir Henry Holland has directed my atten- 
tion to certain pages of Seneca (Nat. Qusest., lib. vi.), in which that author describes his 
having conversed with two centuiions, who, in the early part of the reign of Nero, had 
been sent to seek out the sources of the Nile. With the assistance of the King of Ethiopia 
and other chiefs, they had to so great an extent accomplished their task, that farther pro- 
gress by water was impracticable, for they reached great jungles or marshes ( immensas 
paludes) in which the smallest canoe, containing one man only, could paddle. As, how- 
ever, Seneca speaks also of waters gushing from subterraneous reservoirs as probable 
sources of the Nile, other geographical friends, who were aware of these writings, do not 
believe that they are to be viewed as trustworthy accounts of the origin of the great river, 
A map of the region to the north of Abyssinia, between 35° 37' long. E. of Paris, and 
15 J 17' N. lat., drawn upon the ground in 1857 by Mr. Werner Miinzinger, has been 
published at Winterthur in Switzerland. Besides the small German work of Heuglin, to 
which allusion was made p. 284, when the merits of the old descriptions of Bi'uce were 
brought 
