SHILLONG SERIES. 49 



the south-west of Maophlong^ it is not continuous ; there is no sign of it 

 ahout the junction in the unbroken section due west of Maophlong-, nor 

 for some miles to the north. It was observed^ however, in an analogous 

 position, between the quartzites and the schists, in the sections of the 

 valley of the Umiam, and on the north side of the Masura ridge, which 

 is tfie northern Kmit of the plateau. The rocks are so completely folded 

 that this band is found at all elevations, in the bed of the Bogkpkni as 

 on the ridge of Laisoplia. 



Thfr area of the schists has been very little explored. They present 

 a considerable variety of composition, texture and colour ; some are still 

 soft and shaly ; others show partial cleavage, and in some foliation and 

 mineralization are well developed. The quartzose element is very 

 subordinate. The study of the schists is greatly obscured by the extent 

 to which they are traversed by, and associated with eruptive rock ; over 

 large areas, the two seem inextricably blended. 



The quartzites are not perhaps of greater thickness than the 

 schists, but they come much oftener under notice, being con- 

 spicuously weathered out on all the ridges. As far as is in their nature, 

 they exhibit as much variety as the others. Some of these characters 

 must be due to original differences ; there are compact, sharply bedded 

 varieties and also coarse forms, in which false bedding is as clearly seen 

 as in the original sandstone. So much do they locally and superficially 

 resemble unaltered rock that they have been over large areas mis- 

 taken for, and identified with, the cretaceous rocks of Cherra. Unless 

 where the disintegration is far advanced, a lens always enables 

 one to detect signs of metamorphism. But metamorphism is irregu- 

 larly, and apparently capriciously, distributed; it seems to have 

 little or no relation to the proximity of the great granitic masses which, 

 as will be explained, appear to have been protruded through them. It 

 would seem rather to be locally connected with the degree of disturbance ; 

 thus on the Maophlong ridge, where the strata are nearly vertical, with 



( 199 ) 



