cxiv Report of the Mineralogical Survey [No. 126*. 



splitting generally into slates of moderate thickness, but which are 

 often curved, smooth to the feeling, and having a slight degree of 

 lustre. I think this type owes its peculiar character to the magnesia it 

 contains. It is found between Petorah and Goon ; near the latter place, 

 it is succeeded by a yellow rotten stone, which has apparently ori- 

 ginated in an argillaceous rock of a less schistose character, or perhaps 

 even in calcareo-argillaceous strata. It is remarkable for its rhom- 

 bohedral cleavages, breaking into fragments of that shape on the 

 application of the hammer. It is of arenaceous composition, and its 

 specific gravity is very low, about 1.5. In its vicinity are found small 

 masses of a soft argillaceous limestone, of a light olive colour, which 

 might perhaps be of use in lithography. They form the only type 

 of limestone I have met with in these mountains which hold out any 

 prospect of being available for the purposes of that art. In general, 

 the lithographic stones used in Europe are derived from the secon- 

 dary strata, and even in these, the properties essential to the most 

 perfect specimens seem to be peculiar to a very small tract in Ger- 

 many, neither France nor England having yet furnished stones to 

 compete with those of the former country. 



250. The soft magnesian clay slate of different colours, which is 

 found near Goon, also prevails at Doodar. On the ascent to the Thakil 

 Peak, which lies a little to the left of the route from Petorah to 

 Lohooghat below that village, a bluish grey schist, of a shining lustre 

 is found, traversed by white veins. In ascending from Doodar to 

 the Peak, the rotten stone noticed near Goon, and of a bright ochrey, 

 colour occurs, but undistinguished by the peculiar structure of that 

 rock, the present one giving an amorphous irregular fracture. Above 

 this, lies a fine greywacke schist of a dark blackish grey colour, which 

 passes into a rock that strikes fire with steel. The summit of the 

 peak is a silicious limestone that occasionally passes into schist. It 

 projects in amorphous weather-worn nodules, and is full of veins of 

 flint (var. rhombohedral quartz.) This is not a common mineral, at 

 least in the form of veins, to be found in limestone. It is of two 

 kinds : the one a dark brown, exactly similar to the ordinary gun 

 flints, the other a white opaque substance, occasionally becoming trans- 

 lucent, and not very unlike the mineral called cacholong. These veins 

 are more persistent than the bulk of the rock, which indeed appears 



