1854.] STRACHEY — PHYSICAL GEOLOGY OF THE HIMALAYA. 251 



in any part of the mass, the tendency to transverse rupture would be 

 least where the general coherency was least disturbed, we should ex- 

 pect to find fewest transverse fissures on those lines of minimum 

 longitudinal fracture just noticed. 



Comparing these theoretical views with the observed facts, we 

 find : — 



1st. The existence, in a marked degree, of the longitudinal and 

 transverse fissures, in every part of the mountains. 



2nd. The more open character and greater importance of the 

 longitudinal fissures in the centre of the area, as evinced by the 

 direction of rivers on the Tibetan table-land. 



3rd. The existence of an important line of fissure along the outer 

 margin of the Himalayan slope, as proved by the narrow fringe of the 

 latest formations that everywhere skirts the foot of the mountains, 

 which it is impossible to suppose could have been raised as they are, 

 excepting in connexion with some larger mass. 



4th. The occurrence of two lines of least rupture running parallel 

 to the margin of the area, and intermediate between it and the axis, 

 indicated by the Indian and Turkish watersheds ; these features 

 being dependent for their existence, not on any superior elevation 

 that they attain over other parts of the chain, but only on their 

 continuity, and on the few transverse fissures by which they are 

 broken through. 



5th. The few transverse fissures along the outer margin of the 

 area, which affords a probable explanation of the accumulation of 

 the drainage of considerable areas of the Himalayan slope, into the 

 few great rivers that pass through the outer ranges. 



After entering into some details as to the more important lines of 

 fissure, it was remarked that the presence of more fissures than may 

 seem to be necessary, or of others not in accordance vdth these 

 views, may be readily expected to have been caused in movements 

 anterior to the last great elevation. At the same time, the general 

 parallelism of all the anterior movements to the last is indicated by 

 the constant parallelism of the strike of the strata, the lines of rup- 

 ture, the lines of elevation, and those of the directions of the strati- 

 fied deposits ; although a certain obliquity at the same time does 

 exist, which, however, must be more closely examined before more 

 can be said of it. 



The author then passed to the chronological part of the subject. 

 The age of the granite of the great hue of snowy peaks was first con- 

 sidered, and shown to be probably anterior to the Silurian period ; 

 but doubts still remain on this subject, though the occurrence of 

 rolled pebbles of this rock in the tertiary deposits of the Tibetan 

 table-land, show that the eruption was certainly antecedent to the 

 middle of the tertiary epoch. 



The existence of a coast-line along the Indian water-shed, as in- 

 dicated by a conglomerate-bed at the bottom of the Silurian rocks, 

 was next noticed, with the presumption of the existence of a northern 

 sea, having its boundary along this line during the Silurian epoch, 

 as well as during the Jurassic, and the earlier portion of the Tertiary 



