108 PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
Similarly, the second model should he followed by another in 
which additional elevation has broadened the coastal plain, and 
further volcanic action has complicated the group of cones and 
flows. With greater elevation and age of the coastal plain, it would 
be possible to introduce the development of thoroughly dissected 
doabs; and by drowning these forms, the type of Chesapeake Bay 
and of the Potomac estuary would be illustrated. Another suc¬ 
cession from the young coastal plain would show a cuesta , or longi- 
tudinal flat ridge, with gentle ontlooking slope and relatively steep 
inface, enclosing an inner lowland; this group of features being 
known on the coastal plain of Alabama. Associated with these 
features, there would be certain systematic re-arrangements of drain¬ 
age, such as characterizes regions of this kind. 
When these complications are expressed only in words, they are 
relatively difficult to follow; but when expressed in a series of 
models, in which successive stages are not separated by too great 
intervals, the development of various land forms would be very 
easy even for young scholars to understand. Thus aided in gaining 
an appreciation of the facts of geographical form, it would be a rela¬ 
tively simple matter to exhibit the way in which man takes advan¬ 
tage of these forms in his manner of life. It does not seem too 
much to say that the general introduction of systematic geograph¬ 
ical models in elementary teaching would revolutionize the condition 
of geography in the schools. By the addition of more complex 
forms, the models would form the nucleus of a museum of sys¬ 
tematic geography, in which land forms would be classified accord¬ 
ing to structure and development. Such a museum promises to be 
as useful for the future progress of scientific geography as systematic 
collections of animals and plants have been for the past progress of 
zoology and botany. 
Note on the Construction of the Models. Bv G. C. Curtis. As 
a preliminary step to the construction of the models here described, 
shaded maps were drawn with some care, in order to be sure that a 
genetic sequence of typical forms should be secured. This is 
regarded as an essential, for otherwise it would be hardly possible 
to provide in the first member of the series the proper antecedents 
of all the forms developed in the later members. The drawings 
were based on a careful study of appropriate maps and photographs, 
