4 HAYDEN : GEOLOGY OF SPITI. 
India" (l inch = 4 miles). All boundaries were carefully followed as 
far as possible, but, owing to the small scale and inaccuracies of the 
topographical map, it has frequently been found impossible to re- 
produce the smaller structural details. In addition to this, owing 
both to physical and political difficulties, certain parts of the range 
separating Spiti from Western Tibet were inaccessible, and geological 
boundaries could therefore be drawn only approximately. This is 
especially the case in that part of To-tzo (Western Tibet) which lies 
to the «^ast of the Spiti river, and which could be only rapidly and 
surreptitiously traversed ; for the local inhabitants, although as a 
rule exceedingly friendly and not disposed to place any serious 
obstacles in the way of travellers, have during the last few years jeal- 
ously guarded their frontier, in consequence of a recent attempt on 
the part of a tactless and irresponsible traveller to force his way in 
the teeth of all opposition into the more easterly parts of their 
country. 
( 4 ) 
