66 The American Geologist. January, isos 
That is the principal work of every geological survey the world over. 
He claims, however, that it can be done without a topographic Vjase. 
AVere the writer a practical geologist, such statements would neces- 
sarily impair confidence not only in his ability but in his good sense. 
It is an axiom that no good geological map can be made without a 
good topographic map as a basis. The U. S. Geological Survey found 
itself without such maps except in certain comparatively limited 
areas, and there being no provision under any other organization for 
making them, this survey undertook the task. It was a condition, 
not a theory, that confronted it. Perhaps the Coast and Geodetic 
Survey might have done the work better, but tliat organization was 
not doing it, and on application, declined to do it; therefore the 
geological survey having the means and having legal authority, pro- 
ceeded to do it. 
The writer fortifies liis statement by the assertion that uj) to the 
time the U. S. Geological Survey commenced systematic topographic 
surveys (1882), no geological survey had found it necessary to do 
topographic work. Now tlie fact is, tluit with the exception of a few 
geological reconnoissances, every geological survey, whether under 
state or national authority, had prosecuted topographic work. Under 
national authority, the Hayden, Powell, AVheeler, and King surveys 
made topographic maps. Under state authority, the geological sur- 
veys of New Hampshire, New Jersey, Pennsylvania, North (^^arolina, 
Alabama, Kentucky, Ohio, Michigan. Wisconsin, Missouri, Minnesota 
and California had done the same, prior to 1882, while since that date 
many more have been added to the list. 
In ten years the Geological Survey has surveyed topographically 
an area of 550,000 square miles at a total expense of $2,150,000. Tlie 
average cost per square mile has been a trifle less than $4.00. The 
Geologist objects to this figui'e as being too low for good work — his 
argument is that the higlier the price, the better the quality. But the 
area mapped includes regions surveyed on various scales, chiefly 
1:250,000, 1:125,000 and 1:62,500, which implies a wide range in cost. 
It includes areas where the work has been greatly aided by the sur- 
veys of the General Land Office, the Coast and Geodetic Survey, tlie 
Lake Survey, the Piver Surveys, etc., all of which have been utilized 
and the average cost has thus been greatly reduced. The maps of 
the New England states on the scale 1 :62,500 have cost per square 
mile from $9.00 to $13.00. This cost should imply to tlie Geologist 
good work, since it sets a limit of $10.00 per square mile as being sat- 
isfactory in the matter of expense. But work on the same scale in 
the Mississippi valley in Illinois, Iowa and AVisconsin has cost only 
$2.00 or $3.00 per square mile, and the results are quite as satisfactory 
as in :\rassachusetts and New York where the cost was four or five 
times as great. The dilTerence in cost is due in the main to the 
assistance rendered by the surveys of the General Land Oflice whose 
corners furnish practically all the secondary locations. 
In the third plqce, the (thologjst charges duplication and clashing 
