DESCRIPTIVE GEOLOGY: GENERAL CONSIDERATIONS. 259 



along its southern border — and the fact that it gives us 

 somewhat abruptly, but with perfect finality, a set of 

 metamorphic and crystalline rocks occupying correspond- 

 ing areas and altitudes to those in the Slate zone which are 

 characterised by the historical rocks ranging from the 

 Slates to the Nummulitics. 



Chapter VII.— General Considerations. 



In the foregoing chapters the geological structure of each of the 

 zones has been given in considerable detail. It must not be imagined 

 that every structural item, as collected in the field, has been present- 

 ed to the reader. On the contrary, the great mass of material facti 

 have, I hope, been judicially sifted, so that only such as are of most 

 intrinsic merit in explaining the geological history of Hazara, or 

 necessary to establish the geological features as laid down on the 

 map and sections, have been brought forward. Still the amount of 

 detailed description is considerable, and it would have been very 

 hard indeed if no results of a general nature could be deduced from 

 them. 



As a preliminary to such I may point out that the geological 

 Detailed accuracy of boundaries were laid down on a map twice the 

 map. scale of that accompanying this memoir, and 



that even then much detail had to be suppressed, which, wherever 

 possible, has been inserted in the sections. No one knows better 

 than a geologist within what wide limits geological accuracy as re- 

 presented in maps can vary, but I think I may, from the consider- 

 ations given above, and without egotism, claim that the boundaries 

 01 the various formations are as accurately reproduced on the map as 

 its scale would allow. In most cases my notes and sections would 

 have sufficed to produce a much more detailed delineation had the 

 scale and topography of the map admitted of it. Thus, any super- 

 structure of deduction and generalisation that I shall now attempt 

 to raise on the material furnished in the foregoing chapters must be 

 understood to have a reasonably firm basis in facts as represented 

 S2 ( 259 ) 



