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Three drainage intensity regions of the Allegheny Plateau formed on renewed surfaces in response to conditions imposed by glacial and periglacial processes. Because of the severe transformation of an antecedent surface into streamlined form, postglacial stream concentrations are highest in the north and decrease southward as the degree of glacial modification diminishes, permitting the survival of relict landforms better adapted to normal erosional processes. Southward differences in surface mantle characteristics consonantly affect the generation of drainage line. [ABSTRACT FROM AUTHOR]

Investigations near some of the icecaps of central Iceland show that pressure and winds are markedly affected by the presence of the icecaps under various synoptic conditions. The main effect is of wave formation and descent of dry air, coming predominantly from Polar or Arctic air masses, and the descent of this air is associated with a belt of severe soil erosion in south and central Iceland. A similar effect can also be detected in northern Iceland.

Glacial diversion of drainage has been a factor of first importance in determining the existing pattern of stream courses in regions occupied by Pleistocene continental glaciers. Aside from the well-known, large scale changes resulting from deposit of drift, transection of monor and major water partings by overflows from glacierpond waters was an important item in the reordering of stream courses. The efficacy of this type of erosion does not seem to have been fully appreciated. Deep gorges were evidently eroded with great rapidity by such overflow streams. In some places the cuts thus made served of themselves to confirm postglacial drainage in new channels. Elsewhere glacial erosion modified and commonly greatly enlarge the water-cut overflow channels. There is a marked tendency to compel the glacially reconstructed drainage to arcuate courses which reflect the outline of the normal lobate margins of the ice front. [ABSTRACT FROM AUTHOR]

Colluvial mantles on the mountains of southwestern United States are believed to have formed during colder climates associated with the last glaciation. They imply mean temperatures 10-11°C. lower than those of today and a depression of the timber line by 1,300-1,400 meters. Evaporation rates were about half the present values and by estimating runoff it is possible to reconstruct the full-glacial hydrologic budget of Pleistocene closed lakes. Precipitation was eighty to ninety percent of present values and there was no glacial pluvial. Pollen data can be reconciled with the proposed cold dry climate which has modem homoclimes at higher altitudes and latitudes. [ABSTRACT FROM AUTHOR]

The Weddell Sea in the Antarctica is one of the two indentations of the continent and lies to the east of Palmer Land and west of Coat's Land. It is a major feature of the earth with length of about 700 miles and breadth about 1200 miles. While these strong winds of the glacial anticyclones are sufficiently powerful to force the pack away from the shore, they at the same time bring out snow measured by the millions of tons and at very low temperatures. This, added to the seawater, causes it to congeal quickly when the relatively warm blizzard has been succeeded by the cold calm.

The coastal regions of the Pacific Northwest of the United States have a marine west-coast which in other parts of the world is associated with broadleaf forests of the middle latitudes. In the Pacific Northwest such forests are so limited in extent as well as in the number of species as to be negligible. Estimates indicate that in the area west of the Cascade crest the proportion of the broadleaf trees on a numerical basis amounts only 6 per cent of the entire forest. When broadleaf trees are compared with conifers on the basis of timber volume, their proportion sinks to utter insignificance; the estimated proportion being only 1 : 1000. The following is en enquiry into this absence of a forest type which under similar conditions elsewhere seems to represent the climax association. [ABSTRACT FROM AUTHOR]

Presents abstracts of research papers and speeches on geographic study. Erosion cycle in a rugged mountain region and changes in settlement patterns at the eastern Canadian Arctic; Contributions of U.S. scientists to the geographic knowledge of the Central Pacific; Establishment of a unique climatic study.

The history of the vegetation of the Middle West as of every other portion of our continent, is a history of repeated migrations of diverse floristic elements, arriving in the region from various directions, persisting there for various lengths of time and finally retreating under the pressure of environmental changes which made their position no longer tenable. This history has been complicated by the extinction of old and the differentiation of new species, by the mingling of species of originally different history and by the persistence of isolated relics of early migrations.