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adjustment aggraded altitude anticlinal base-level basin beds belt block branches canon Carboniferous channel cliff climate condition consequent course Cretaceous curves cusps cycle deepening degradation denudation deposits depression described dissected drainage earth elevation eroded examples explanation facts farther faulting fiords flood plain Geol geology glacial erosion glaciated valleys glacier graded graded slopes hanging valleys headwaters hence highlands illustration initial kind lake land forms lateral valleys ledges lower lowland main valley maps marine mass mature meander ment Meuse monoclinal Moselle mountain normal observation original peneplain Permian physical geography physiographic piedmont plateau pre-glacial present processes range ravines reached reentrant region relation ridges river rocks scarp shore-line side streams slope spurs stage strata structure sub-aerial surface Susquehanna swinging synclinal systematic teacher terraces tilting tion to-day Triassic trough uplands uplift valley floor valley sides waste Westfield river worn
Page 72 - Every river appears to consist of a main trunk, fed from a variety of branches, each running in a valley proportioned to its size, and all of them together forming a system of valleys, communicating with one another, and having such a nice adjustment of their declivities, that none of them join the principal valley, either on too high or too low a level...
Page 250 - AB thus measuring its average initial relief. The surface rocks are attacked by the weather. Rain falls on the weathered surface and washes some of the loosened waste down the initial slopes to the...
Page 131 - To describe, without rising to the causes, or descending to the consequences, is no more science, than merely and simply to relate a fact of which one has been a witness.
Page 377 - ... level in this connection, as the action of a running stream in wearing its channel ceases, for all practical purposes, before its bed has quite reached the level of the lower end of the stream. What I have called the...
Page 257 - ... separated. The forces of crustal upheaval and deformation act in a much broader way than the processes of land-sculpture; hence at the opening of a cycle one would expect to find a moderate number of large river-basins, somewhat indefinitely separated on the flat crests of broad swells or arches of land surface, or occasionally more sharply limited by the raised edge of faulted blocks. The action of the lateral consequent streams...
Page 561 - He is conducted to the places where the transitions of nature are most perceptible, and where the absence of former, or the presence of new circumstances, excludes the action of imaginary causes. By this correction of his first opinion, a new approximation is made to the truth; and by the repetition of the same process certainty is finally obtained. Thus theory and observation mutually assist one another; and the spirit of system, against which there are so many and such just complaints, appears,...
Page 377 - We may consider the level of the sea to be a grand base level, below which the dry lands cannot be eroded; but we may also have, for local and temporary purposes, other base levels of erosion, which are the levels of the beds of the principal streams which carry away the products of erosion.
Page 349 - ... Considerable as the inequalities of altitude are, frequent study of the maps and repeated views of the uplands from various hill tops impress me much more with the relative accordance of their altitudes than with their diversity. I cannot admit that the appearance of accordance from hill top to hill top is an optical deception. There is an important matter of fact behind the appearance. The comparative evenness of the uplands in Connecticut was recognized and well described by Percival over half...