570 E. C. ABENDANON 



granite chain extending toward the north, thus forming a transition 

 to the Birman chains (p. 303). At Tenasserim, on the neck of 

 land east of the Mergui Islands, there are outcrops of Upper 

 Carboniferous (p. 303) as well as of Archean rocks (I, 599). This 

 Upper Carboniferous seems to extend far to the north in the valley 

 of the Salwen, and at Moulmein notably (latitude =ti6|°N.), in 

 the form of limestone, it occupies a large area (p. 599). However, 

 this eastern zone of the Birman chains, to which we have come, 

 consists principally of Archean rocks (p. 593). To the east of 

 Moulmein the chains extend northward and north-northeast, 

 beyond Xieng-Sen, which is situated on the Mekong, in the northern 

 part of Siam (Vol. Ill, Part i, p. 290). Other ranges joining the 

 former between Xieng-sen and Vien-tiane (also on the Mekong, 

 but further down) take a northeast-southwest direction, and, 

 decreasing in height, gradually disappear toward the southeast and 

 the south, under the Siamese plain (p. 290). Then toward the 

 southeast comes Siam, an immense unknown land, which, being 

 connected with a vast area of granulite and granite, leads us to 

 the low and old massif of Cambodge, of which we will speak later 

 (pp. 290-91). Let us first follow the Birman chains toward the 

 north. 



According to Griesbach, the limestones of Moulmein seem to 

 continue northward up to the highland of the Shan, where the 

 Permian limestone is folded, the folds having been leveled (Vol. Ill, 

 Part I, p. 281). .Then long ranges composed at first of crystalline 

 schists and further north of gneiss lead north to Mandalay on 

 the Irawaddi. And here again, in the Northern Shan States, we 

 find once more the oldest fossiliferous strata which we had left 

 in latitude 2 2°S. on the eastern coast of Australia. In fact, Suess 

 writes (Vol. Ill, Part i, p. 278) : "Le chemin de fer et la route qui, 

 de Mandalay, ont. ete construits vers le N.E. par Thibaw jusqu'au 

 bac de Kunlon^ sur la Salouen, longent sur de grandes distances la 

 direction (N.N.E. ou E.N.E.) des roches. Les terrains les plus 

 anciens sont a TOuest; au voisinage de Mandalay se montrent les 

 couches inferieures de la serie, peut-etre cambriennes, puis le Silurien 

 inferieur, le Silurien superieur, un gres rouge pince dans les plis, 



' Kun-long, Just to the south of the Tropic of Cancer. 



1 



