306 MCMAHON : PETROLOGICAL NOTES ON SOME PERIDOTITES, ETC., 



contact with the carboniferous rocks/' " To the south-eastward of 

 Skiu the southern tertiary boundary runs near the right bank of the 

 Markha river" . . " In the valley of the Markha along this 



boundary line, numerous small masses of trap are met with, which is 

 generally of a more crystalline structure than the trap to the west- 

 ward of the Za*nskar river ; and it is probably pebbles of this trap 

 which are included in the higher tertiary conglomerates. In places, 

 as on the upper Gya river, this trap has burst through the pre- 

 tertiary rocks, and frequently has included in itself masses of the 

 latter crowded with crinoids. To the south-east of the Gya river the 

 band of carboniferous rocks dies out, and the tertiaries on both their 

 borders are in direct contact with the older crystallines. From a 

 little to the westward of the Puga river to the extreme easterly limit 

 of Kashmir territory, an irregularly wedge-shaped mass of the trap 

 separates the sedimentary tertiaries from the older crystallines, and 

 it is near the southern border of this trap that the extensive mineral 

 deposits of the Puga valley chiefly occur" (p. 113). 



At page 115, the author notes the occurrence in the Marpo ravine 

 in the Dras valley of a "serpentine, indistinguishable from that of 

 Pa'skira," which he thought might " belong to the palaeozoic traps." 



The following specimens collected by Mr. R. Lydekker are 

 described in the following pages : — 



No. 94 — 212. Gabbro from Peak D. 24, Ladakh. 



„ 94—217. Peridotite (Lherzolite) from Markha valley, Ladakh. 



„ 4- 210 Serpentine (Bowenite), Skiu valley, Shigar, 



„ 94 — 29. Hornblende-rock from Ladakh. 



„ 94—218. Volcanic ash from Wangat, Ladakh. 



„ 91 — 224. Fine-grained ash from do. do. 



Mr. R. D. Oldham writes as follows regarding " The Indus 

 Valley Tertiaries" in the Records, Geol. Surv. Ind., Vol. XXI, 



P. 154:— 



"As these have already been described by Mr. Lydekker more 

 fully than I could do, I shall confine myself to considering the con- 

 clusions that may be drawn from them. 



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