112 GRIESBACH: GEOLOGY OF THE CENTRAL HIMALAYAS. 



Girthi Valley. 



The Chor Hoti section (3 in pi. 3) is again perhaps the most 

 Ch6r Hoti and Pain- favourable locality for fossils ; nearly every frag- 

 kanda - ment of weathered debris found on the hill slopes 



contains traces, but mostly in a very bad state of preservation. 

 The lower part of the steep cliff which forms the last ascent of the 

 Painkanda peak (19,340'), is composed of the dark-blue concretionary 

 Ctfr^Z-limestone (6) of the devonians. 



In the" Girthi valley I found the limestone (6) close to the Girthi 



camping ground at the base of a high snow- 

 covered peak (20,344'), composed of the upper 

 carboniferous rocks ; the C^r^Z-limestone (6) dips about 40 to 45 

 north-east below the red Crinoid limestone (7), of the upper car- 

 boniferous which forms the high cliffs through which the Girthi 

 river has eroded its bed at that spot. It is part of the great 

 north-west to south-east zone, which though easily traced by its dis- 

 tinctive colour, I could only cross at a few places ; the Rimkin 

 sections (see pi. 2, pi. 10, and sect. 3, pi. 3), those of the Girthi 

 valley and lastly the Milam sections show clearly the same sequence 

 of formations. 



The steep cliffs on the right bank of the Silakank stream are all 

 Carboniferous ; red capped by very conspicuous beds of densely red 

 Crinoid limestone (7). to re d-brown limestone (see pi. 6), which rests 

 on the G?rtf/-limestone (6) of my sections. 



Both this division and the overlying white quartzite (8) vary 

 much in thickness. In the Niti area I have found its thickness from 

 350 to 500 feet and is there very uniform in lithological character. 

 Generally it is an earthy limestone of a brick-red to brown colour, in 

 beds of 6 to 12 inches in thickness, with occasional masses of almost 

 unstratified limestone with silicious concretions. Shining plates of 

 Crinoids, and now and then perfectly preserved Encrinite discs are 

 scattered throughout the rock. Other fossils are rare and badly pre- 

 served, — usually in casts only, amongst which an Orthoceras species is 

 commonest. 



I found the upper boundary of the formation not well defined ; the 

 ( 112 ) 



