( 4 ) 



8. The Kaulee-ya-olioung ; and, finally, 



9. The Bhaunee and Kyon-lee choungs, uniting into the Malaka choung. 

 The Pegu river, ronning from north to south, receives the Wou, Thaymay, Kodoo-gway 

 and Khayasoo choungs. , i lu 



The Nga-mo-yeat or Pazwoondoung stream, also called the Pounglin river, with the 

 Mahooya ohoung as principal feeder, runs in the same direction as the Pegu river, of which 

 it might almost be said to be a feeder. 



The full of the principal rivers is inconsiderable, and amounts in the Irrawaddi and Sittang 

 rivers, between the sea and Prome and Tounghoo respectively, to not more than about 6 

 inches in a mile. 



2. Qeology of Pegu, aafar as connected icith the Flora, 

 Wlien speaking of the geological formations of Pegu in connection with the vegetation, 

 it must be borne in mind, that a botanist's treatment of the geological features of a country 

 differs to a great extent from the treatment of the same subject by a professional geologist, 

 inasmuch as a botanist hos not to take into account all tliose minute details, which are re- 

 quired for fixing the age of the rocks, &o. The botanist has simply to consider the 

 extent and quality of the rocks and soils which are represented in his botanical district, and to 

 draw inferences from them upon the vegetation that grows on each of those formations. Only 

 when he enters into speculations as to the age of floras, their origin and the later geographical 

 distribution of plants, has he also to take into account such geological disturbances as have 

 taken place in former epochs. 



The geology of Pegu itself is very simple and uniform, for the hills are composed solely 

 of sandstone, skirted along their base by a broader or narrower strip of diluvium, interrupted 

 by a deeper or shallower alluvium, wherever choungs come down from the hills ; and succeed- 

 ed by the vast alluvial plains, through which the Irrawaddi and Sittang flow. It is owing to 

 this uniformity in the nature of the rocks, that we can so easily understand the distribution 

 of plants, while the Martaban or Karen hills, &c. offer many apparent anomalies, which 

 can be explained only after more close study. 



We have then to consider here the following principal formations : 

 1. Alhivitim, deep and shallow. 



2. Bilmium, in the form of laterite, sand or diluvial clay and loam. 

 3. Softer grey sandstone, almost destitute of fossils. 

 4. Calcareous sandstone, often full of fossils. 



1. Alluvium. The alluvial plains stretch along the principal rivers, for more than 150 

 miles to the north, where, at Tounghoo and Prome, they have an absolute elevation of about 

 00 feet only. The surface soil iu the valleys of the Sittang and Pegu rivers, as well as in 

 that of the Irrawaddi, is usually a grey stiff clay of greater or lesser depth, resting often on 

 loose sand or diluvial loam. Diluvial formations of smaller extent crop out in various locali- 

 ties in the midst of alluvium, and especially also in the deltas of the rivers, in which respect 

 these deltas greatly differ from the Gangetic Delta in Bengal. Wells, in the villages all over 

 the Irrawaddi alluvium from the banks of the Irrawaddi to the base of the hills, are rarely 

 dug deeper than to about 12 to 24 feet in average. 



The vegetation of these alluvial plains is tidal as far up as the salt water influences 

 them ; passing then into savannahs and savannah-forests, enclosing often swamp forests in 

 depressions. Towards tlio hills, the savannah forests gradually pass into lower mixed forests. 

 The presence of Lower Mixed forests may be ascribed to two causes, viz., to the lesser depth 

 of the alluvium, and to the neighbourhood of the hills. 



Generally, the effect of deep alluvium upon vegetation is twofold. First, it prevents a 

 large number of trees from establishing themselves, and secondly, it affects the growth of 

 those which do take possession of the soil, rendering them short stemmed and in many cases 

 crooked. 



2. Diluvium. The diluvial formations stretch nearly all along the base of the Pe^u 

 Yomah, until they converge at the northern extremities of the alluvium, viz., near Prome 

 and above Tounghoo, with the same formations of the Arracan and Karen hills, where they 

 cover a more or less extended area, variously interrupted by sandstones and alluvial forma- 

 tions. 



This diluvium is composed of various kinds of lateritic rocks, and of gravelly soils, such 

 as sand or loam ; sometimes of very stiff clay. Conglomerates chiefly composed of coarser or 

 finer quartz or ferruginous sandstone pebbles, either cemented by ferrugiuous loams, &o. or 

 loose, are also frequent, especially in the Prome districts. Along certain tracts the diluvial 

 formations do not crop out at all, but are covered with a thin layer of alluvium, which then 

 usually bears the peculiar low forests, which combine the character of Eng and lower mixed 

 forests. Such is the case especially along the base of the Yomah from the latitude of Thousay 

 down to the Pazwoondoung valley near Pounggyee. 



