SHILLONG SERIES. 47 



I imagine that the boundary can be clearly made out^ for^ as far as I 

 have seenj the greatest metamorphism of the Shillong series takes place 

 towards the south-east^ away from the area of the older metamorphics. 



AH the metamorphic rocks I saw in the Gkro district — at Seju, 

 Tura^ Harigaon, Singm^ri — I considered to belong to the gneiss. So 

 also were those in the far north-east, at the falls of the Kopili, and on 

 the N^mb^ near Golaghat. 



9. The Shillong Seeies. 



This series and the igneous rocks connected with it form the basis 

 of the table-land throughout the whole section of the Khasia district — 

 from Cherra on the south to the Dinghei and Mksura ridge beyond the 

 Umikm north of Shillong. It is of course a venture to speak of it 

 as one series upon so slight an acquaintance, for it comprises a great 

 thickness of strata showing considerable variety of composition. It 

 would be only still more venturesome to attempt a separation upon the 

 same information. In any case, there are the important characters in 

 common of general parallelism and of equal and local metamorphism. 



The series consists of a considerable thickness of quartzites, locally 

 largely conglomeritic, and of an unascertained thickness of earthy rocks 

 in the state of slate and of schist. The distribution of these rocks 

 seems to have but little connection with the actual configm-ation of the 

 table-land. The same may be said of the contortions displayed in the 

 strata; it will, indeed, be difficult to bring these structural features into 

 any general order, the observed differences of strike are so great. But 

 the area over which they have been observed is too small to afford data 

 for discussion. Intimately connected with the "deposits of the Shillong 

 series, there are large developments of hypogene rocks, both trappean 

 and granitic. 



The two types of deposit forming the Shillong series are not indis- 

 criminately associated; they occupy distinct positions, and must have 

 been deposited consecutively. As far as I have been able to form an 



( 197 ) 



