STRATIGRAPHICAL ELEMENTS : INFRA-TRIAS. 19 



underlie beds of Trias age, and that therefore they are older than 

 those Trias beds. But all attempts at a closer limiting of their 

 position must be of a somewhat speculative nature. 



There is one hypothesis, however, of a very suggestive nature 



to which Mr. Oldham has referred in the 



Possible homotaxis of Manual, but without more than a passing com- 



the conglomerate with , 1 • ,■%_ r ,1 1 1 



the boulder-bed of the ment, 1 viz. } that of the conglomerate being 

 Salt-Range. homotaxially related to the Boulder-bed of the 



Salt-Range. In the days when Wynne and 

 Waagen worked in Hazara the Boulder-bed of the Salt-Range was 

 believed by them to belong to the Cretaceous epoch, and as such it 

 could of course have no affinity with beds lower than the Trias. But 

 I cannot help thinking that had the above authors seen this con- 

 glomerate with our present knowledge of the Carboniferous or older 

 age of the Boulder-bed before them, they might have been tempted 

 to provisionally correlate the two. It is often remarked that a shore 

 deposit like this conglomerate can never be contemporaneous with a 

 similar deposit in another place, even in the extreme case of the 

 bed being in continuous exposure between the two places. This 

 is no doubt true, if we take our time-units sufficiently small. On 

 the other hand if we look at the case broadly (as we are bound to do 

 in the absence of characteristic fossils) we may quite reasonably 

 correlate homotaxially two such formations in distinct but nearly- 

 related districts, provided (1) that there is no general palaeontological 

 data opposed to it, and (2) that the petrological sequences involved in, 

 and the physical conditions of the earth at the time implied by, those 

 deposits, are analogous. 



As I had the good fortune to spend a season in the Salt-Range 

 just before proceeding to Hazara, and as the Boulder-bed and its 

 relations were matters to which my attention was particularly directed, 

 I may perhaps indicate in the following parallel columns the points 

 of likeness and difference between the Infra-Trias basal conglomerate 



1 2nd Edn., p. 138. 

 C2 ( 19 ) 



