! : KV TRAVERSES 47 



with them as to the joining- up of their various geological 

 boundary-lines. 



The extent of ground which can be examined and 

 mapped in a year by one of the geologists of the Survey 

 varies with the caju< itv of the surveyor ; with the nature 

 of the ground, whether level, easily traversed, and re- 

 vealing comparatively few geological sections, or rough 

 and high, laborious to climb or cross, and abounding in 

 ravines and crags, all of which must be examined ; and 

 with the simplic ity or intricacy of the geological sin 

 and the number of boundary -lines that require to be 

 traced. A man might complete the survey of half a 

 county lying upon the Chalk of the south-east of England 

 before another could get over more than a part of a single 

 parish in such intricate geological and rough mountainous 

 ground as that round Snowdon, or that in the west of 

 Sutherland and Ross-shire. 



Let me place before the reader some statistics re- 

 specting the rate of work in the Geological Survey of 

 Scotland, where much of the ground is hilly and where 

 the geological structure is often far from simple. The 

 average annual area of ground geologically examined and 

 surveyed by each officer in the Lowlands was not much 

 below too square miles. This amount was performed 

 by an average daily walk of from ten to fifteen miles, ex- 

 clusive of Sundays, holidays, wet days, and the time spent 

 indoors in reducing the field-work and preparing it for 

 publication. The part of the year devoted to actual 

 surveying may be set down as about 200 days, or it may 

 be perhaps rather more than that. We see, then, that in 

 the more level tracts of the country one of the members 



