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Landmarks in the History of Science » Geoscience » The Explanatory Description of Landforms, 1924, inscribed and signed by William Morris Davis

The Explanatory Description of Landforms, 1924, inscribed and signed by William Morris Davis

Autor: W. M. Davis
Cod: 8610
In stoc: Da

Detalii produs ''Naught looks the same for long…
Waters rush on, make valleys where once stood plains;
           hills wash away to the sea.
Marshland dries to sand, while dry land
           becomes stagnant, marshy pool.
From Nature, springs erupt or are sealed;
           from earthquakes, streams burst forth or vanish.

In Metamorphoses, the Roman poet Ovid, echoing Pythagoras, alludes to geomorphology: the study of the forms taken by the earth’s surface, and what causes them. Almost 19 centuries later, William Morris Davis, devised a clear, concise, descriptive, and idealized model of landscape evolution that revolutionized and in many ways created this field of study.

He had a slow start in academe, with few accolades for either his early teaching or his early research. In 1882, President Charles William Eliot [of Harvard] even advised him to seek employment elsewhere. But Davis was tenacious, as well as a keen observer of nature, a master of logical deduction, and a brilliant synthesizer of disparate observations and ideas. From his own field observations and studies made by the original nineteenth-century surveyors of the western United States, he devised the theory for which he is best known: the 'Erosional Cycle.'

Alongside tectonic uplift, Davis identified rivers and their tributaries as the primary agents for altering the appearance of landscapes, and distinguished three anthropomorphically named stages of landscape evolution, all initiated by uplift. In ‘ 'Youth', narrow, incised river valleys locally decrease the growing elevation differences between ‘Uplands' and 'base-level' caused by uplift. In ‘Maturity', these elevation differences and the number of branching streams reach their maxima, while valleys cut downward and broaden. In 'Old Age', the ever-broadening valleys hold meandering channels that create rolling lowlands (‘peneplains'). In a complete cycle, the stages transition gradually unless interrupted and reset by subsequent uplift (‘Rejuvenation'). This theory, published between 1886 and 1911, moved geomorphology, despite some opposition, from purely local descriptions to global explanations - and in the history of his discipline, time is often demarcated as ‘before' or ‘after' Davis.''

                          Philip S. Koch, Harvard Magazine, September - October 2018

''The American geographer William Morris Davis has revealed the ‘life cycle’ of rivers. This was a revolutionary idea; there was not a scientist wedded to the passé  descriptive geography still dominant among us who was not scandalized by the Yankee’s bold concept. That antagonism, however, was short-lived and feeble. In a single stroke, one simple monograph, The Rivers and Valleys of Pennsylvania (1889), recorded the thrust of what had preceded it and staked out a new direction in geographical analysis. It did so by linking river form with structure of terrain, thereby complementing interpretation of the impassive facies with geological analysis, and by explaining the causes of the most transitory features and discovering in the visible lines of the earth’s changing physiognomy the eloquent expression of the natural energies that had molded it and continue ceaselessly to transform it.

In the end it surprised no one that Davis, carrying his new doctrine out to its ultimate implications, arrived at a kind of monstrous physiology and dramatically described the complex vicissitudes of the millenarian existence of our teeming watercourses, revealing them to be possessed of an ebullient infancy, a rebellious adolescence, a self-controlled maturity, and a melancholy old age or decrepitude, as though they were stupendous organisms subject to the laws of competition and selection leading to triumph or annihilation more or less in accordance with how well they adapt to external conditions.
It is not my intent here merely to repeat the ingenious biographer of the rivers of Pennsylvania by explaining his admirable theory, which represents a case of an impressive charge, a daring ‘rush’ of imagination and fantasy, within the quiet sanctuaries of science. One needs only note that it has been generally accepted and rests on solid inductive data.

Despite the variations of theater in which they operate, all watercourses pass through inevitable stages in regular rhythms. At first indecisive, errant, fragile, they run according to chance among topographical features, as though seeking a cradle in each and every low area of the land, gathering in numerous incoherently distributed lakes, where they come to rest. Then, when their first regular carved-out drainage troughs become defined channels into which the water from the rains flows and gathers, currents form, carving out incipient beds and initiating, with the tumultuous energy of the cataracts, a centuries-long stage of clash with the solidity of the earth. 

Finally, when the structural obstacles are overcome, a course is established and a riverbed defined, the river is fully constituted, with its stable tributaries, a continuous slope descending in regular curves, a thalweg adjusted to the contexture of the soil and to the morphological differentiation that reflects its various segments - from the headwaters where the wild flows of its former torrential regime remain, to the midcourse, which characterizes its current stage of development, to the lower stretch, which prefigures its decrepitude and where it spreads out to build, with the settling out of the silt that it bears imperceptibly, the very alluvial plain through which it runs.
This is the phase of maturity. The river is in the plenitude of its life, after the complex molding of all its features is complete. It reaches that stage at the end of a persistent struggle that sometimes comprises the entire geological history of the region through which it flows.
There has not been a single point in all the trajectory of hundreds if not thousands of kilometers that it did not attack, no single grain of sand that it did not move, balancing its upstream excavations with its downstream deposits, constructing itself in consonance with the universal tendency toward stable states. It has finally acquired its balanced longitudinal profile, which, still steep in the high areas where the flow is fastest and the volume lowest, continuously diminishes along the course of its fall until it reaches the near-horizontal base level of its mouth. At that point the elements are reversed, and the system’s dynamic equilibrium is reached by the inverse relationship between liquid mass and speed of flow.
Whatever the details, once it reaches this stage, the elements of its thalweg, projected onto the vertical plane, approximate the shape of one arm of a gigantic parabola with its curve opening upward.
That is the geometrical expression of a complex mechanical fact. And while the tendency toward the figure may often be distorted or contravened in areas of variable resistance, where the rocks that the river has revealed protrude and create the antagonism of the cataracts, in the areas of homogeneous terrain the parabolic curve is clearly described as the definitive form of the longitudinal section of all rivers at the end of their tribulated evolution.’’
                       Euclides da Cunha, Rivers in Abandon, in: The Amazon. Land
                       Without History, Oxford University Press, 2006, pp. 18-20

The Explanatory Description of Landforms / Die erklarende Beschreibung der Landformen, 1924, Leipzig-Berlin, B. G. Teubner; large 8vo; xxxi, p. 566, [iii] : index, 212 illus., xiii plts. Light wear, no staining, hinges tight. Fine condition. The book is inscribed and signed in ink on title page by author, W. M. Davis, to California Geologist Edwin Verne Van Amringe whose small private library stamp is on the front pastedown.

We added: The Folded Helderberg Limestones East of the Catskills, Cambridge, 1883, Bulletin of the Museum of Comparative Zoology at Harvard College, Geological Series Vol. 1, No. X pp. 311-329 + large foldout with 16 diagrams of Helderberg Rocks & large geological cross section (16 x 35 inches) & identical separate copy that had been hand watercolored. Good condition. An offprint signed and annoted in pencil by William Morris Davis.

Price: USD 150,000.00