DAVIS : THE HARVARD GEOGRAPHICAL MODELS. 101 
it can hardly be thought that these characteristic physiographic 
elements are altogether wanting in nature. The relative breadth of 
the straths and the doabs, the local relief of the doabs above the 
straths, and the degree of dissection of the doab borders are so 
briefly or imperfectly described that no accurate mental picture of 
the plains can be constructed. No sufficient account is given of the 
manifold relations that must exist between the form of the plains 
and the distribution and occupation of the people. It may be fairly 
contended that if a traveller in those regions were familiar with a 
type example of a coastal plain, such as the second model exhibits, 
his attention to many physiographic features would be awakened 
where it now slumbers, his observation would be immediately 
directed to critical localities, and his records would be very intel¬ 
ligible and satisfying to his readers. 
Third model. A mountainous region descending to an irregular 
shore line. In marked contrast to the comparatively even shore 
lines of the first and second models, the land here borders very 
irregularly on the sea. The ridges advance in promontories. Out¬ 
standing islands are seen beyond the ends of some of the headlands. 
Long branching bays enter between the ridges, penetrating far 
inland and terminating in rather acute points. There is a systematic 
relation between land form and shore outline. Every valley 
descends into a re-entrant of the shore line; the larger the valley, 
the longer the re-entrant. The ridges that separate the valleys also 
serve to divide the bays. 
The irregular outline of the land cannot be explained by the action 
of present processes. The headlands are wasting where the strong 
outer waves are cutting cliffs at their ends. Some of the coves 
receive the waste from the cliffs in the form of concave beaches. 
The bays are filling at their heads where the streams are building 
deltas. The continuation of these processes would reduce the shore 
line to comparative simplicity of outline. Indeed, in some earlier 
period than the present, the shore line must have been somewhat 
more irregular than it now is. Before the cliffs were cut, the head- 
lands were longer and sharper than today. Before the concave 
beaches were swung between the headlands, the coves were deeper 
than now. Before the deltas were built, the bays were longer and 
