418 J. F. KEMP — GEOLOGICAL BOOK-KEEPING 



ephemeral value, to be discarded after the final map and report are 

 prepared. It may be and usually is assumed that they will be of no 

 further use and will never be consulted by another or subsequent ob- 

 server. It is true that field books are often only intelligible to those 

 who write them, and, as usually recorded, a later reader without the 

 personal guidance of the original recorder would have difficulty in in- 

 telligibly following a traverse with numerous observations ; yet the field 

 book is necessarily the most detailed of all the records, and provided 

 it is intelligible, it contains what is of greatest value to a subsequent 

 worker. Its weak point is the frequent lack of a systematic, simple, 

 elastic, and uniform method of recording locations, since, if the writing 

 can be read at all, the uncertainty alone arises from the location of the 

 observation. 



Over this method the system here set forth certainly has advantages 

 both in the field and in the office. 



The second principle on which observations may be S3 r stematically 

 grouped is that of time. An observer who makes no index or compiled 

 summary usually, when trying to recall what he has seen in a partic- 

 ular locality or region, does so by running back in his mind over his 

 movements in various years and months until in this way he can estab- 

 lish the particular note book which is sought, yet as note books accu- 

 mulate this process is slow and tedious and often elusive. As compared 

 with it a method based on locality is much to be preferred. If note 

 books are indexed or provided with a table of contents, the search is 

 simplified, but even then, should a searcher wish to know everything 

 which he or his colleagues or predecessors had observed in a certain 

 square mile of a certain quadrangle, it would be a slow process to find 

 this information by any scheme, however well indexed, if based on the 

 time principle. 



The third principle is that of locality, and is the one suggested in this 

 paper. So far as the accurate recording of observations is concerned, 

 other methods may be as good as this one, perhaps even better, but none 

 lead up to the compilation book, which is the great saver of time and 

 effort. So long as a spot or a square mile or any larger area can be 

 located on a standard map one can turn in a moment to a compilation 

 book and find the condensed records of all observations, and, if the plan 

 is systematically carried out, not only of one, but of many observers. 

 The detail and completeness of the work is at once apparent and the 

 progress of knowledge much facilitated. 



The principle of locality has, finally, incomparable advantages, be- 

 cause, so far as areal geology is concerned, observations are alone of 

 value when accurately tied up with a definite place. 



