Il6 MIDDLEMISS: PHYSICAL GEOLOGY OF SUB-HIMALAYA. 



of the older rocks is more thoroughly worked out. How many 

 heart-rendings will there then be should our theories too hastily 

 formed dissolve like a dream before the clear daylight of advancing 

 knowledge. Yes, we had better keep to the task imposed, as closely 

 as human nature will allow. 



Attention has already been drawn, in the section up the Pel£ni R., 

 Structure imbriquee to the disposition of the disturbance zones, to 

 (ecaileuse). their great extension lengthwise in the form 



of bands, to the northerly dip of their composing formations, and to 

 the reversed faults bounding them on their northern edges. They 

 are disposed in what has been elsewhere called structure imbriquee 

 [ecaileuse)'} but with this peculiarity; that the uppermost member of 

 each step or zone is younger as we near the outer margin of the hills. 

 Let us look at this structure a little more closely. We have seen 

 that it is extremely probable that the reversed faults belonging to this 

 structure imbriquee were not contemporaneous, but successional ; and 

 I think there are certain considerations which will enable us to date 

 their succession with some approach to accuracy. If we cast our eye 

 over the map accompanying this memoir, and the smaller scale map 

 of part of GarhwaV we cannot help being struckby the peculiar manner 

 in which a long narrow zone carries, as its uppermost member, a still 

 narrower outcrop of some one formation. For very great distances we 

 may see on the map, running parallel with the reversed fault, a thin 

 line of colour representing a single rock stage. I may first instance 

 the nummulitic band, which with a total thickness of a few hundred 

 feet extends for 30 or 40 miles thus without any very marked in- 

 crease in the width of the zone. I may also mention the thin band of 

 Siwalik conglomerate which continues from the Kotri dun to the 

 Rdmganga R. and many of the members of the Sub-Himalayan 

 series and the still older mesozoic formations. Lastly, the Sub-Hima- 

 layan group taken in its entirety is also an example of the great 

 extension of a narrow belt of strata following a reversed fault for 

 immense distances. 



1 See " Les Dislocations de l'ecorce terrestre " par Emm. de Margerie and Dr. 

 Albert Heim. 



2 Rec, G. S. I., Vol. XX., p. 26. 



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