186 BAILEY WILLIS — GRArHIC FIELD NOTES. 



for the same record averages seven and does not exceed ten miles a day. 

 Our experience further shows that these averages added to the distances from 

 and to lodging places, lunch being taken afield, form a suflScient day's 

 travel for horses or men, when performed day after day throughout the field 

 season. Thus the quantity of product by this method is about equal to the 

 endurance of means of transportation. 



Quality, if we consider the work of different men, is a very variable fac- 

 tor; but if we compare the value of graphic notes with that of written 

 notes taken by the same man we shall get a definite result. We find that 

 graphic notes are more concise, more definite, more accurate than verbal 

 notes ; graphic notes are more easily understood by a fellow-observer, be he 

 chief or assistant ; graphic notes directly present facts in visible relations, 

 words do not; graphic notes are capable of immediate transfer to the base 

 map, verbal notes must first be translated into graphic form. He who takes 

 graphic notes in the field arranges facts, one by one, each in its place and 

 in proper relations to all others ; he who takes verbal notes forms a mental 

 image of these relations, often an erroneous one, Avhich must be corrected by 

 a subsequent plat. Moreover, the possession in orderly arrangement of all 

 facts observed up to any point in a piece of work enables the observer to 

 plan ahead and directs his attention to missing links in the chain of evi- 

 dence. Hence graphic notes, even if more slowly taken than verbal notes, 

 are usually more complete and save waste and repetition of field work. 



In the oflfice there can be no question of the saving of time accomplished 

 by graphic methods of field work. 



In one instance two adjacent atlas sheets covering 1,000 square miles each, 

 which presented structural problems in terms of similar stratigraphic units, 

 were surveyed by a geologist and his assistant ; the notes recorded in the 

 one consisted of statements of distances wheeled oflT on roads and the corre- 

 sponding geologic facts — a verbal record ; the notes taken in the other were 

 all platted directly in the field. Field work for the former was 34 days, for the 

 latter 30 days. Office work for the former consumed four weeks, for the 

 latter but two weeks. 



The preparation of maps is but routine work, the aim of which is the 

 elucidation and presentation of geologic problems ; to reduce the time de- 

 manded for routine is to gain time for study and is therefore a step toward 

 improvement in the quality of the final result. 



The graphic methods which I have indicated are methods of accurate 

 work; in the Appalachian province they are also methods of detailed work; 

 but this is a condition of special application, not an inherent necessity. 

 Running a meander line facilitates but does not necessitate the observation 

 of geologic facts. Nevertheless it is true that the knowledge that every fact 

 observed can be noted in its proper relations tends toward detailed observa- 

 tion. 



