GEOLOGICAL CONDITIONS IN RELATION TO EARTHQUAKE. jq5 



vat ion of about 4,000 feet; above the level of the sea, whereas 



the approximate elevation of Mandalay itself is only 315 feet. 



South of Lat. 22°, the geology of the interior is practically unknown. 



The ascent to the plateau from the plains does not proceed in 



one long steep line, but in a series of step- 

 Asoent to tin; Shan 1:1. r i i c • i i i 



Plateaufrom the Plains. llk( formations, separated by fairly level ex- 

 panses of country. La Tonche has demon- 

 strated that these are merely portions of the main plateau let 

 down by a succession of parallel faults, running in a north and 

 south direction, the position of each being regularly marked by the 

 steeper rises (see PI. 6). 



Towards the north and north-west, the gneisses and associated 

 crystalline rocks of the Rubv Mines and Man- 

 Character of the flaky districts form the foundation upon which 

 oonntry towards the ■ 



north and north-west. ail the later strata have been laid. They build 



a succession of roughly parallel ranges which 

 extend from north-east to south-west. To the north, these ranges 

 increase in elevation, their crests rising to an average height of 

 from 1,000 to 6,000 feet above sea-level. There is no doubt that 

 this crystalline mass is continuous with the gneisses and crystalline 

 limestones which are found about the Burma-China frontier in 

 the Bhamo district, though the intervening region has still to be 

 geologically surveyed. (*) 



To the south of the Ruby Mines district, the gneisses occupy 

 the whole of the country between the Chaung Magyi and the 

 Irrawaddy. The long range of hills which runs parallel to the 

 river opposite Mandalay, in the Sagaing district, is composed of the 

 same rocks, and although the Palaeozoic rocks of the Shan plateau 

 come right down to the edge of the plain, the Arehaans them- 

 selves pierce the alluvial floor occasionally, and are found in places 

 like Sagyin and Mandalay J I ill rising in small abrupt outliers. 

 The gneisses appear again at the foot of the plateau scarp near 

 Kyaukse, and from this point they are believed to form a con- 

 tinuous band, extending along the edge of the Shan plateau to the 

 sea near Moulmein.( 2 ) 



1 ('. L. Griesbach: Geological Sketch <>f the Oonntry (forth of Bhamo. lice. 

 Gcol. Surv., Ind.. Vol. X.YV. p. 127. 



L. Vi>n Loc/.v in Graf, iii'i.i Szeohenyi's " Reise in Ostasien," Vol. I. p. 77U. 

 .1. Coggin Brown: Contributions to the Geology of Yunnan. I. The country 

 between Bhamo and Teng-yueh. Bee., Oeoi. Svrv.,Ind., Vol., XLHL pp. 174-205. 



2 ('. 8. Middlemisa : Report on n Geological Reconnaissance in parts of the 

 Southern Shan States and Karenni. (hneral Report, Geo!. Sun:, lnd., J899-190U, 

 pl28. 



