STRATIGRAPHICAL ELEMENTS : SLATE SERIES. 15 



In the first place there is the striking fact that the slates underlie 

 the Infra-Trias, and therefore the Trias of Hazara. This is a relation 

 that cannot be called in question (see remarks on the base of the 

 next rock group), for a great unconformity divides the two formations. 

 In the second place as regards their composition, structure, great 

 thickness, and wide distribution they appear to resemble much of the 

 Panjal system of Kashmir (Lydekker), and they most certainly are 

 identical in the above characteristics with the great azoic slate 

 and schistose slate formation of the Outer Himalaya of Garhwal and 

 Kumaun (Middlemiss) and the corresponding Vaikrita, and perhaps in 

 part Haimanta systems of the Central Himalaya (Griesbach). In the 

 first of these compared areas the slate formation is known to underlie 

 the Kuling = Carboniferous series, whilst in the last it underlies rocks 

 in which Silurian fossils have been found : and there is no repetition 

 in any of these regions of a similar great slate series higher up 

 among the younger historical rocks. 1 Lastly, in the Salt-Range of 

 the Panjab, the lowest known fossiliferous rocks are presumably 

 Lower Cambrian in age since they contain an Olenellus fauna; and 

 here, also, above that horizon we have no trace of anything of the 

 nature of a great slate series, and, so far as the earth's crust is 

 exposed beneath those Cambrian rocks, there is also no slate series 

 exposed below that horizon. 



Putting the above facts in order we may deduce the follow- 

 ing:— 



(1) That where a similar slate or schistose slate series is known 



in India, it always occurs below the oldest known fossili- 

 ferous rocks of that part, and never above any one of 

 them. 



(2) That as regards the Salt-Range, where the most perfect 



evidence of stratigraphical superposition is obtainable, 

 if any slate series exists at a great depth below the oldest 



1 Mr. Griesbach, however, tells me of a remarkable occurrence of nummulitic 

 rocks and others in Baluchistan converted by the intrusions of traps into schists and 

 phyllites. 



( 15 ) 



