Page:Encyclopædia Britannica, Ninth Edition, v. 1.djvu/78

62 some of considerable extent, which attain a height of more than 10,000 feet. The mountains in various parts of the country rise to 12,000 and 13,000 feet above the sea, and some of the peaks of Samen are said to reach to 15,000 feet, and to be always covered with snow. The average height of the range which divides the streams flowing to the east from those that flow westward is about 8000 feet, rising to 10,000 or 11,000 in the south, and sinking in the north. The whole country presents the appearance of having been broken up and tossed about in a remarkable manner, the mountains assuming wild and fantastic forms, with sides frequently abrupt and precipitous, and only accessible by very difficult passes. The Samen range of mountains are the highest in Abyssinia, and together with the Lamalmon and Lasta mountains form a long but not continuous chain, running from north to south.

The principal rivers of Abyssinia are tributaries of the Nile. The western portion of the country may be divided into three regions, drained respectively by the Mareb, the Atbara, and the Abai. The most northern of these rivers is the Mareb, which rises in the mountains of Taranta, flows first south, then west, and afterwards turns to the north, where it is at length, after a course of upwards of 500 miles, lost in the sand, but in the rainy season it falls into the Atbara. The Atbara, or Takazza, rises in the mountains of Lasta, and flowing first north, then west, and again turning to the north, at length falls into the Nile, after a course of about 800 miles. The Abai, Bahr-el-Azrek or Blue River, the eastern branch of the Nile, and considered by Bruce to be the main stream of that river, rises from two mountains near Geesh, in lat. 10 59 25&quot; N., long. 36 55 30&quot; E., about 10,000 feet above the level of the sea. It flows first north to the Lake of Dembea or Tzana, then takes a long semicircular sweep round the province of Godjam, and afterwards flows northward to about the 15th degree of N. lat., where it unites with the Bahr-el-Abiad, which has now been ascertained to be the true Nile. The Hawash, the principal river of eastern Abyssinia, rises about lat. 9 30 N., long. 38 E., and, flowing in a north-easterly direction towards the Red Sea, is lost in Lake Aussa, lat. 1 1 25 N., long. 41 40 E. The principal lake of Abyssinia is the Dembea, which lies between 11 30 and 12 30 N. lat., and 37 and 37 35 E. long., being about 60 miles in length by 40 in width, and containing a number of small islands. It is fed by numerous small streams. The lake of Ashangi, in lat. 12 35 N., long. 39 40 E., is about 4 miles long by 3 broad, and upwards of 8000 feet above the sea.

The fundamental rocks of Tigre, and probably of all Abyssinia, are metamorphic. They compose the mass of the table-land, and while they occupy no inconsiderable portion of its surface, they are exposed, in Tigr6 at least, in every deep valley. The metamorphics vary greatly in mineral character, &quot; every intermediate grade being found between the most coarsely crystalline granite and a slaty rock so little altered that the lines of the original bedding are still apparent. Perhaps the most prevalent form of rock is a rather finely crystalline gneiss. Hornblende-schist and mica-schist are met with, but neither of the minerals from which they are named appears to be so abundant as in some metamorphic tracts. On the other hand, a compact felspathic rock, approaching felsite in composition, is pre valent in places, as in the Sum defile, between Komayli and SenafeY There are a few exceptions, but as a general rule it may be asserted that in the neighbourhood of the route followed by the British army, so much of the country as is more than 8000 feet above the sea consists of bedded traps, and tliis is probably the case in general over Abys sinia. &quot; Between the traps and the metamorphics a series of sandstones and limestones intervene, one group of the former underlying the latter. The limestone alone is fossiliferous, and is of Jurassic age.&quot; &quot; On the route to Magdala volcanic rocks were first met with at Senafd, where several hills consist of trachyte, passing into claystone and basalt. Trap hills, chiefly of trachyte, are dotted over the country to the southward as far as Fokada, a distance of nearly 30 miles. Here a great range of bedded traps com mences, and extends for about 25 miles to the south, pass ing to the west of Adigerat.&quot; At Meshek, two marches south of Antalo, &quot; the route entered high ranges entirely composed of trap, and thence no other rocks were seen as far as Magdala.&quot; &quot; The trappean rocks .belong to two dis tinct and unconformable groups. The lower of these is much inclined, while the higher rests on its upturned and denuded edges. Denudation has evidently been going on to a great extent in this country. One of its most striking features are the deep ravines which have been worked out by the action of the streams, sometimes to the depth of 3000 or 4000 feet. &quot; How much of the Abyssinian high lands has been removed by these great torrents, and spread as an alluvial deposit over the basin of the Nile 1 &quot; &quot;Probably over the whole of northern Abyssinia there existed at least 4000 feet of bedded traps, of which now only a few vestiges remain.&quot; W. T. Blanford.

Abyssinia is said to enjoy &quot;probably as salubrious a climate as any country on the face of the globe.&quot; Parkyns. The heat is by no means oppressive, a fine light air counteracting the power of the sun ; and during the rainy season, the sky being cloudy, the weather is always agreeable and cool, while the rain itself is not very severe. In certain of the low valleys, however, malarious influences prevail before and after the rainy season, and bring on dangerous fevers. On the higher parts the cold is sometimes intense, particularly at night. The natural division of the seasons is into a cold, a hot, and a rainy season. The cold season may be said to extend from October to February, the hot from the beginning of March to the middle of June, and the wet or monsoon period from this time to the end of September. The rainy season is of importance, not only in equalising the temperature, increasing 