HISTORICAL SUMMARY. 349 



considerable distance, while the thickness of the deposits would 

 correspond to the irregularities of the sea-bottom. And as these 

 Pliocene rocks contain, so far as is known, few organic remains, 

 we should find it difficult to learn, supposing that a fresh upheaval 

 brought the whole series above water, what interval of time had 

 elapsed between the deposition of the highly inclined fluviatile 

 strata below and the marine beds resting upon them. 



The conditions that prevailed at this time in the Shan States 

 appear to resemble very closely those which 



N«SSSrtSina With are described b y Bai % Willisl as obtaining 

 in north-eastern China at the beginning of 

 the Sinian period. He thinks that the older rocks, represented by 

 the crystalline Archeeans and the Hu-t'o system, the latter of which 

 appears to correspond rather closely with the Chaung-Magyi series, 

 had been reduced by subaerial denudation to a peneplain, and — 



" that the lowest strata of the Man-t'o (lower Cambrian) formation were 

 laid down in the shallows, lagoons, and flood-plains of a very low, flat coast, 

 where weak waves, feeble shore currents, and rivers interacted." 



Regarding the actual contours of the eastern coast of Gond- 

 wana land but little can be said at present. 

 YunnlTplnLwL™^'' We know that the ancient crystalline rocks 

 of the Shan States extend northwards towards 

 the head waters of the Irrawaddy, where they are connected in some 

 way, as yet not fully understood, with those forming the main 

 axis of the Himalaya ; and that to the east of them, in Yunnan, a 

 sequence of fossiliferous rocks is found, comparable with that of 

 the Shan States ; but unfortunately we know very little of the country 

 between the Irrawaddy and the Brahmaputra. All we do know 

 is that metamorphic rocks extend for a long distance to the 

 north-east of Assam, the Miju Ranges of Dr. Maclaren. 2 And it 

 seems probable that these rocks may have constituted from 

 the earliest ages a prolongation to the north-east of the Gondwana 

 continent, cutting off the basin of the southern ' Tethys, ' which 

 washed the northern shores of that continent, from the an- 

 cient Chinese ocean, of which the Yunnan and Shan seas 

 formed a part. In this way I would account for the marked 

 discrepancy that exists, until we arrive at the Permo-Carbonifcrous 

 epoch, between the faunas of the Himalaya and of the Shan States, 



1 Research in China, Vol. II, p. 32. 



2 Geology of Upper Assam ; Record',; Geol. Surv. hid., Vol. 3$XXI, Pt. 2, p. 181. 



