GEOGRAPHICAL PROGRESS AND DISCOVERY. 



297 



lake was observed an ancient volcano; five 

 miles farther commenced a series of volcanic 

 rocks, porphyry, tufa, and agglomerates, form- 

 ing mountains several thousand feet high, 

 which skirt the northern end of the lake. At 

 the northwest corner of the lake, in the plain 

 through which the river Jumbaka passes, were 

 seen a number of perfectly formed recent cones 

 rising to the height of 300 feet. Between Ny- 

 assa and Tanganyika are first mountains 8,000 

 feet in height, then a level country, 4,000 to 

 6,000 feet in elevation, of clay slates and schists, 

 with intrusive masses of granite. Near Lake 

 Tanganyika are red and variegated sandstones, 

 considerably disturbed. On the opposite side 

 of the lake, near the southern end, is a sudden 

 wall, which lowers the level from 5,000 to less 

 than 3,000 feet. This is probably the continu- 

 ation of the fault noticed above. Feldspar is 

 the predominating rock from this point north- 

 ward, huge masses of feldspathic rock forming 

 mountains on the east and west sides of the lake. 

 Beyond the Chansa range of metamorphic 

 rocks with a feldspathic foundation, the sand- 

 stones are again found in the Uguha country. 

 They spread over a wide area, extending down 

 the Lukuga and the Congo Valley as far as Lake 

 Moero. They probably mark the bed of an im- 

 mense inland lake. When rounding the south 

 end of Tanganyika, Thomson took occasion to 

 explore the disputed lake Hikwa, or Likwa, as 

 he calls it, from Kapufi, latitude 8 south, 

 longitude 32 25' east. This lake is sixty to 

 seventy miles long, and fifteen to twenty wide. 

 It lies two days east of Makapuli, in a deep de- 

 pression in the Lambalamfipi Mountains. A 

 large river, called the Mkafa, which rises in 

 Kawendi, and drains Mpimbwe and most of 

 Khonongo and Fipa, empties into it. Thom- 

 son is sure that it has no outlet. The debated 

 question of the Lukuga outlet of Lake Tan- 

 ganyika seems to have been finally settled by 

 the exploration of Mr. Hore, an English mis- 

 sionary at Ujiji. This mysterious stream, which 

 Cameron saw flowing out of Lake Tanganyika, 

 with a distinct current in the direction of the 

 Congo, but which presented itself to Stanley's 

 view as a shallow water-course, half marsh, 

 extending but a short distance from the lake, 

 carrying an insignificant volume of water 

 brought down by small creeks, with a feeble 

 current, into the lake, was found by Hore to 

 be a swift river proceeding out of the lake. 

 The stream as it issued from the lake had a 

 depth of from three to five fathoms. It nar- 

 rowed soon, and the current became dan- 

 gerously rapid. At the point where Stanley 

 ceased his explorations, the stream-bed be- 

 coming smaller and overgrown with reeds, 

 the current was too swift for the canoe. Half 

 a mile farther the rapids end, and the river 

 widens. Ascending an eminence, Hore saw 

 the river flowing far away into Urua. It is a 

 frequent phenomenon in Africa for the rivers to 

 become choked with vegetation. After accu- 

 mulating for a number of years in such thick 



masses as to sometimes stop the current, the 

 aquatic plants will decay, and at the next rise 

 of the water will be carried down, leaving a 

 clear channel. When Cameron visited the Lu- 

 kuga, there was a bed of aquatic plants cover- 

 ing the river, but a current flowing between 

 and underneath them ; when Stanley saw it 

 they had probably settled to the bottom, and 

 as the lake was presumably at its lowest 

 stage, there may have been little or no outflow. 

 This mass must have since decayed, and been 

 swept out in succeeding rainy seasons, forming 

 a channel for the swift-flowing river seen by 

 Hore. The growth of water-plants for twenty 

 months unchecked, in the White Nile, formed 

 an obstruction to navigation which it has re- 

 cently taken the Austrian Marno five months 

 of unremitting toil to remove, so as to reopen 

 the river to navigation and trade. Thomson, 

 the commissioner of the Royal Geographical So- 

 ciety, was carried across the lake by Hore upon 

 his vessel. Thomson, on his homeward jour- 

 ney, came to the Lukuga, and endeavored to 

 follow it down to the Lualaba. He succeeded 

 in descending considerably beyond the point 

 where Hore was obliged to leave the river, 

 but was unable to accomplish his purpose, by 

 reason of the hostile actions of the natives. 



AMEEICA. One of the most interesting facts 

 in physical geography which has been estab- 

 lished by the geographical exploration of the 

 Territories, conducted by Clarence King, is 

 that the operations of nature which caused the 

 great prehi.-toric sea, called by geologists Lake 

 Bonneville, to dwindle down to the dimensions 

 of Great Salt Lake, are now reversed, and that 

 the filling up process has commenced. Great 

 Salt Lake now loses by evaporation kss water 

 than flows into it, and has risen eleven feet 

 since 1866. The natural basin of Pyramid Lake 

 is now 7 full, its level having risen nine feet ; and 

 Winnemucca Lake is being filled up from the 

 overflow, having risen twenty -two feet, and 

 doubled in area, within the same few years, 

 The upheaval which has been detected on the 

 shores of Hudson Bay extends far up into the 

 region of the lakes of British America and the 

 Mackenzie River basin. Abbe Petitot, a Cana- 

 dian missionary, who has traversed the vast and 

 little explored territory between Great Slave 

 Lake and the Arctic Sea in every direction, 

 found that several of the lakes and chains of 

 lakes were drying up. The deep granite basin 

 of one of the lakes he found completely bare, 

 and in it he saw a yawning chasm shaped like 

 a funnel, through which the waters had been 

 drawn into some subterranean channel. The 

 Indians believe that there are several of these 

 underground rivers in this region. The Mac- 

 kenzie River district is not adapted to coloniza- 

 tion, in the belief of Abbe Petitot and other 

 travelers who have visited it; but its upper 

 waters, the Liard, Peace, Elk, and Athabasca 

 Rivers drain a fertile region, in which coal is 

 found and petroleum in abundance. 



Reports have long been circulated in Cen- 



