LADAKH, NORTH-WESTERN HIMALAYA. 305 



Mr. R. Lydekker's account of the {l southern tertiary boundary 

 and the large series of volcanic rocks met with along this line " 

 will be found at pp. 111-115, Memoir of the Geology of Kashmir 

 (Memoirs, Vol. XXII, Geol. Surv. Ind.). 



"At the north-western extremity of the tertiary zone," 

 Mr. Lydekker writes, " the purple shales of Pciskim are overlain by 

 a great mass of basaltic trap, or lava, which in this region consists of 

 greenish anamesite, weathering to a pale-brown colour. Although 

 there is no visible instance of the intrusion of the trap into the beds 

 of the sedimentary rocks, yet the relations of the two are such as to 

 indicate that the trap is the newer rock. It has, however, been 

 already shown that trap pebbles are contained in the higher tertiaries 

 to the south-east, and it may, therefore, be pretty safely inferred that 

 the emission of the trap took place during some part of the time of 

 the deposition of the tertiaries" (p. m). 



The band of trap has in places, as at Shargol, a width f( as much 

 as ten miles." It is occasionally " much mixed up " with altered 

 tertiary sedimentary rocks, the " remnants of the sedimentary ter- 

 tiaries which probably once extended continuously over the whole 

 area, but which have been broken up and altered by the eruption of 

 the volcanic rocks." 



Mr. Lydekker traces the outcrop of the trap from point to point, 

 but the details need not be given here ; and he notes that lt in the 

 neighbourhood of Lcimayuru " it is " much involved with palaeozoic 

 rocks." 



" The trap in the above-mentioned area," Mr. Lydekker con- 

 tinues (p. 112), u has been described as composed of fine-grained 

 anamesites, greenstones, basalts, serpentines, and a few amygdaloids 

 and, according to Dr. Stoliczko., of gabbro and diallage rocks. No 

 porphyritic trap occurs, and when worn, most of the pebbles acquire 

 a dark-brown glaze." 



The traps gradually die out to the westward of the Zinskar river, 

 and the " main mass of the sedimentary tertiaries comes into direct 



c 3 ) 



