In August, 1928, the writer made a study of the freshwater solution caverns of Bermuda, and their relation to the general geology of the islands has been productive of some observations and conclusions. Various kinds of obligations have been incurred in connection with this study; since it is intended that more complete publication will follow none of these obligations will be acknowledged here. The work was carried on by financial support. extended through the Division of Geology of Harvard University.

As a result of wide recognition in recent years of extensive overfolding and overthrusting, it seems to have become generally admitted that continents have actually moved horizontally in times of orogeny; but the problem as to how and to what extent such horizontal movements were effected has continued to be an irritating cause for heated disputes and also a fertile ground for wild speculation. In making the present attempt to attack this controversial problem, it is not intended to deal with the merits or demerits of the several species of theories or hypotheses connected therewith, but simply to direct attention to certain groups of geotectonic phenomena found in Eastern Asia and elsewhere, and also to the mechanism responsible for their production as may be attested by experimental means. In this way it is hoped that mere speculation may be eliminated.

The genera Endophyllum and Spongophyllum were founded by H. M. Edwards and J. Haime (1851 p. 393 and p. 425),2 upon Devonian Corals from South Devonshire. Their descriptions of these (1851, pp. 394 and 425; 1853, pp. 233 and 242), though clear as far as they go, nevertheless leave room for further details, and their figures (1853, p1. lii, fig. 6; pl. liii, fig. 1; and p1. lvi, figs. 2, 2a–e) unfortunately do not include longitudinal sections of either of their two species of Endophyllum. Later workers on Devonian corals—C. Schlüter (1889, p. 50) and F. Frech (1885, p. 74; 1886, p. 87) have differed widely from the authors in their interpretation of the genera, and therefore a revision of the type-species is desirable.