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Tagula, the largest member of the Louisiade archipelago east of New Guinea, is a mountainous island, 30 miles long by nine wide and 2645 feet in height. Like its neighbors, it is composed of deformed and greatly eroded schists and slates; all the shore lines are embayed; hence the islands may be regarded as parts of a long mountain range of similar structure in northern New Guinea, which have been isolated by strong subsidence. Tagula stands in the eastern part of a vast lagoon enclosed by a great barrier reef, measuring 112 by 30 miles; the western part of the lagoon is divided into a northern and a southern compartment by a chain of small satellite islands; the lagoon floor in each compartment. is a smooth plain with maximum depths of 49 and 46 fathoms in the broadest parts. The narrower parts of the lagoon are shallower, evidently because a given quantity of inwashed reef detritus has there caused a greater aggradation. An exceptional feature is the occurrence of 26 minute islets, mostly from 40 to 150 feet high, probably residuals of a former elevated reef, in the northwestern half of the present reef. Two smaller barrier reefs and a few small atolls with shallower lagoons are found near by. The lees depth of these lagoons, like that of the narrower parts of the Tagula lagoon, is undoubtedly due to the greater efficiency of aggradation by inwashed reef detritus -in lagoons of small area. Not far to the north, Misima, a mountainous island, measuring 22 by 10 miles, with a height of 3500 feet, has no barrier reef but is terraced by several uncomformable elevated reefs; hence in addition to the general subsidence of the region as indicated, by the isolation of its parts, this island has suffered upheaval in recent time. The smooth floor of the Tagula lagoon cannot be due to the presence beneath it of a smooth platform abraded during the lower stands of the ocean in the Glacial period, because the survival of the minute islands in the barrier reef and the absence of spur-end cliffs on the larger islands prove that no extensive abrasion, either by the normal ocean or by the lowered ocean of the Glacial period, has taken place. Hence the islands must have been protected by living reefs all through the Glacial period has taken place. Hence the islands must have been protected by living reefs all through the Glacial period. The depth of the Loni-iade lagoons are essentially accordant with the depths of lagoons of similar size in the open Pacific. Hence as the reefs in this region of demonstrated subsidence appear to have been formed by upgrowth from island foundations of uneven form, and as the lagoons within the reefs appear to have been given smooth floors of ordinary depths by the inwash of reef detritus without the aid of abraded sub-lagoon platforms, it. follows that similar processes may have produced the similar reefs and lagoon floors of the open Pacific; and, further, that stability of reef foundations and the abrasion of sub-lagoon platforms at a standard depth, as assumed in the Glacial- control theory of coral reefs, are no more essential in the open Pacific than in the Louisiade archipelago. In other words, the Louisiade reefs and lagoons give strong support to Danvin's theory of reef upgrowth and. lagoon aggradation on subsiding foundations; and thus warrant the acceptance of that theory for many other reefs and lagoons-and especially for atolls-in regions where evidence as to the stability or instability of foundations and as to action or inaction of low-level abrasion in the Glacial period is either less decisive or wanting. [ABSTRACT FROM AUTHOR]

Explores the Rocky Mountains of Colorado. Determination of the altitude of the loftiest ranges; Repeated application of the results announced for the Boulder district by the studies; Contrasts between the visits of 1869 and 1910.

The article focuses on geographical lessons that can be derived from the Colorado Canyon. The gradual weathering from the flow of water, and not by the convulsion of the earth, has produced the canyon. The process was illustrated by views of the valleys of Hudson and Connecticut in which the hills are leveled into fields in some cases. The presence of strata in the banks of a river indicates that there had been an older mountain region.