1889.] Methods and Models in Geographic Teaching. 577 
rule and not the exception ; and several of the examples already 
given illustrate it. The coastal plain of the Carolinas has suffered 
a moderate depression since its valleys were defined pretty much 
in their present form, and their lower courses are thereby slightly 
submerged. Thus arise the estuaries that characterize our At- 
lantic coast, and these are presented in the fourth model. The 
old base-level plain of the upper Missouri no longer stands at the 
low level in which it was worn down, but has been elevated a 
thousand feet or more, and hence all its rivers that had settled 
down to a quiet old age of little work, have been rejuvenated, 
and are now beginning a second cycle of life. They run swiftly, 
in well-defined, narrow valleys, even though the enclosing rocks 
are soft ; and they are sometimes interrupted by waterfalls, even 
when their volume, is as large as that of the Missouri above Fort 
Benton. Manifestly, therefore, the elevation of the old plain is 
relatively recent ; very little advance has yet been made in the 
development of its second cycle. The same kind of complexity 
appears in the high plateaus of Utah and Colorado : the high- 
level surface in which the canons are cut is not an original surface 
of construction, but is a surface of considerable irregularity, as 
has already been mentioned ; part of the irregularity is due to 
great fractures which have broken the country into massive 
blocks and lifted them a little unevenly, and part is due to the 
incomplete base leveling of the region during a previous cycle of 
development, when the elevation was less than now. The com- 
bination of old and new forms thus explained is the subject of 
the fifth model. A wonderful addition is made to our apprecia- 
tion of a country when all these factors in its history are recog- 
nized as contributing essentially to its topography. 
Is it not worth while to tiy to acquire the broader comprehen- 
sion of geography that comes from understanding its meaning ? 
Can we not make immediate practical use of such terms as in- 
fantile, young, adolescent, mature or middle-aged, old, and very 
old? Do they not recall all the significance of certain selected 
or idealized typical examples that have been studied, being in this 
like the terms that the botanist employs to so great advantage ? 
No botanist would admit the superiority of paraphrases over 
