Geography in the United States.- — Davis. 177 
ferences deduced from well-established physical laws. It is 
entirely possible that there may be some errors in the deduced 
elements of the ideal type-breeze, but it may be confidently as- 
serted that the errors will be replaced by the truth through the 
methods involved in observing, imagining, and checking, guid- 
ed by the conception of the type, sooner than the truth will be 
discovered by blind observation unguided by the aid that a 
well-defined type affords. 
It is the same with an alluvial fan ; an element of land 
form that has, by the way, more similarity to a mountain breeze 
than appears on first thought. Observation shows only the ex- 
isting stage of the surface of a fan ; the fully developed type- 
fan includes the structure as well as the surface, the process 
and the progress of formation, extended into the future as well 
as brought forward from the past. There can be no question 
that the explorer who is equipped with a clear conception of a 
type-fan can do much better work in observing and describing 
the fans that he may find than will be done by an explorer who 
thinks he can dispense with all idealized types, and who pro- 
poses simply to describe what he sees. The shortcomings of 
the simple observational method would be less if it were not 
so difficult to see what one looks at and to record what one sees ; 
but any one who has had experience in field studies knows how 
far short seeing may be of looking, and how far short record- 
ing may be of seeing. The best results in geographical inves- 
tigation can only be obtained when every legitimate aid to ob- 
servation and description is summoned ; and, of all aids, that 
furnished by carefully considered types, reasonably classified, 
is the greatest. When large and complicated features, such as 
valley systems or cuestas, are to be described, the need of types 
is vastly increased. Hence one of the most important and prac- 
tical suggestions that can be made toward the maturing of 
geographical science is to cultivate the geographical imagi- 
nation in the direction of acquiring familiarity with a large, 
systematic series of well-defined ideal types. As progress is 
made in this direction there will be profitable advance from that 
narrow conception of geography which is based on the school- 
day study of names, locations and boundaries — the only con- 
ception of geography that many mature persons in this country 
possess — to a wider conception in which everything studied 
