232 GEOGXOSV OF INDIA. 



wise show that this beautiful precious stone ranges from the 

 equator to the vicinity of the north pole. The following is 

 an enumeration of the heights above the sea at which several 

 of the primitive rock-formations have been noticed : — 



F«t. 



A. cavern in primitive limestone near the Sutledge 6500 



Mountain near the Sutledge, composed of gneiss 8350 



Eastward of the Tarhegang mountain, at the head of the rivulet 

 Ripsang, the rocks are gneiss, granite, mica-slate, and quartz- 

 rock, with tourmaline 11,000 



Pass of Bruang, mica-slate, gneiss, granite, containing tourma- 

 line and garnet 15,000 



The RoUor or Shatul pass, gneiss 15,000 



Mountains near to the Shatul pass, mica-slate, gneiss, and 

 granite 15,556 



2. Transition Rocks. — On the primitive formations rests 

 a vast deposite of rocks of the transition class, principally 

 consisting of clay-slate, graywacke-slate, graywacke, flinty- 

 slate, gypsjdn, and transitton-limc stone. Fossil organic re- 

 mains first appear among these deposites. The ammonite is 

 the most celebrated, on account of the superstitious value 

 attached to it. The heights stated under are probably 

 formed of transition clay-slate, and therefore belong to this 

 section : — 



Feet aboire the Sej. 



Overhanging the town of Marang, a mountain of clay slate 12,000 



Tungrang pass, clay-slate, with pyrites and mica 13,740 



Mountains of clay-slate on the Chinese frontier, containing am- 

 monites 16,200 



Mountains in the neighbourhood of Chrang, of blue clay-slate — 18,000 



Mineral Substances useful in the Arts found in the Primi- 

 tive and Transition Rocks of the Himmalehs. — We shall notice 

 the rocks and minerals in the following order : — 1. Rocks. 

 2. Saline minerals. 3. Inflammable minerals. 4. Metallic 

 minerals. 



1. Rocks. — Granite. — Many fine granites occur in the 

 Himmalehs, which, owing to their remote localities, are as 

 yet of but little value. A beautiful gray porphyritic gratiite 

 occurs, however, close to the cantonment of Ahnora, which 

 would furnish ornamental pillars or slabs of any size. 



Clay-slate. — Of this rock, so useful as a roofing material, 

 many extensive deposites are known, but hitherto they have 

 not been quarried. 



