362 LA TOUCHE : GEOLOGY OF NORTHERN SHAN STATES. 



sented at times by a monoclinal flexure, as in the case of the 

 Kyaukkyan scarp described below, they recall the system of vertical 

 faults on the plateau of Colorado described by Gilbert 1 and Dut- 

 ton, 2 and the} 7 are apparently due to local and deep-seated sub- 

 sidences of the rocks below the surface. 3 The fact that they 

 follow the maximum degree of tangential folding in point of time 

 seems to me to suggest that the cause of the subsidences may 

 have been an easing off of the compressive forces, when the 

 reaction might have resulted in the production of a certain 

 amount of tensional stress, and consequently a slight opening out, 

 as it were, of the folded strata. 



The effects of these subsidences are usually manifested at the 

 surface in the form of vertical scarps of lime- 

 au sea ps. stone, often running in a direct line for sev- 



eral miles across the plateau. The sagging of the strata on one 

 side of the fissure and their stability on the other are well exempli- 

 fied in the case of the great Kyaukkyan scarp 

 Kyaukkyan scarp. , , , . J \ 



so often referred to m these pages. A short 



distance to the north of the point where it is crossed by the 

 railway at Kyaukkyan this dislocation is hardly perceptible on the 

 Burface, though it probably continues for several miles to the north 

 along the valley of the Nam-panhse, where the direction of the 

 movement appears to have been in the opposite sense, that is to 

 say, a downthrow on the eastern side of the fault, from what 

 it certainly is to the south. Immediately to the north of Kyauk- 

 kyan the dislocation takes the form of a monoclinal roll or flexure 

 in the limestone of the plateau, but a line of actual fracture 

 quickly appears near the crest of the flexure, as may be seen at 

 the point where the railway crosses it. Further to the south the 

 crest remains perfectly level, backed by a plateau rising very 

 gradually towards the edge of the Gokteik gorge, but the flexure 

 increases in importance, while at the same time the fault itself 

 appears as a line of vertical cliffs just below the crest, until the 

 differential movement becomes so great that the older Palaeozoic 

 rocks beneath the limestone are exposed along the face of the 

 scarp, which by this time has reached a height, relative to the 

 plateau below, of some 3,000 feet. Along the base the edges 



1 Geology of portions of Nevada, etc. ; U. S. Geol. Surveys W. of 100° Meridian, Vol. 

 Ill, pp. 48-57. 



2 Geology of the High Plateaus of Utah ; U. S. Geol. Survey, 1880, pp. 25-54. 



3 Das Antlitz dcr Erde, Vol. I, pp. 1C4-187. 



