TRANSACTIONS OF SECTION E. 939 



geoloL'y, as by Suess, Lapworth, and Michel- Levy. Thus Elie de Beaumont re- 

 garded the form of the continents as determined by the mountain chains, which he 

 correlated into a regular geometrical network ; while Lapworth regarded the dis- 

 tribution of land and water as due to a series of great earth-folds, the arches 

 forming the continents, and the troughs forming the ocean basins. Suess has 

 treated the subject synthetically ; he has shown that the structure of the globe 

 can be explained by subsidences in the crust when subterranean support is removed 

 by the shrinkage of the internal nucleus, and by the movements of elevation which 

 jn-oduce the chains of fold-mountains. Siiess's view explains the structure of the 

 continents and ocean basins, but not their arrangement. To settle this problem 

 fuller knowledge is needed as to the distribution of land and water in past times. 

 Neumayr's attempt to settle this question for the Jurassic was premature, and his 

 conclusions are untenable. We are thus still dependent upon the deductive systems 

 for suggestions as to the most profitable lines of research. Elie de Beaumont's 

 famous scheme attached undue importance to linear symmetry and was too artificial. 

 It led, however, to the tetrahedral theory of Lowthian Green, which regards the 

 world, not as shaped like a simple tetrahedron, but as a spheroid slightly flattened 

 on four faces. Such flattenings occur on hollow, spherical shells, when they are 

 deformed by uniformly distributed external pressure. The oceans would occupy 

 the four depressions thus produced, and the laud masses occur at the angles and 

 along the edges. The existing geographical arrangement is in general agreement 

 with this scheme ; for as the tetrahedron is hemihedral the assumption that the 

 lithosphere is tetrahedral explains the antipodal position of land and water, the 

 excess of water in the southern hemisphere, and the southward tapering of the 

 land masses. The main lines of the existing system of fold-mountains have a 

 general agreement with the arrangement of the edges of a tetrahedron. Some 

 striking deviations occur, but are explicable by the variations in the composition 

 of the lithosphere, and the existence of impassive blocks of old strata which have 

 moulded the latter movements. The Unes of the old fold-mountains of the Hercy- 

 nian system may have beeu tetrahedrally arranged, with the axes occupying 

 different positions from those of the great Cainozoic mountain system. So far, 

 however, there is no completely satisfactory theory of geomorphology, for which 

 w-e must wait for further information as to the distribution of land and water in 

 successive epochs of the world's history. For the historical method promises more 

 reliable results than the deductive method. 



2. The Great Indian Earthquake of June 12, 1897. By R. D. Oldham. 



The earthquake of June 12, 1897, in India was the largest and, with a few 

 possible exceptions, the most violent of which there is any record. The area over 

 which the shock was sensible was not less than 1,750,000 square miles, while the 

 focus occupied an area of 200 miles in length and 50 miles in width. 



Landslips on an unprecedented scale were produced in the Garo and Khasia 

 Hills, and in the Himalayas north of Lower Assam. A number of lakes hare been 

 produced by changes of level due to the earth-movements by which the earthquake 

 was caused, and the mountain peaks have been moved both vertically and hori- 

 zontally. Monuments of solid stone and forest trees have been broken across by 

 the violence of the shaking they have received. Communications of all kinds were 

 interrupted ; bridges were overthrown, displaced, and in some cases thrust bodily 

 upwards to a height of as much as 20 feet, while the rails on the railways were 

 twisted and bent. Earth fissures were formed over an area larger than the United 

 Kingdom, and sand rents, from which sand and water were forced in solid streams 

 to a height of 3 to 5 feet above the ground, were opened in incalculable numbers. 



The loss of life was comparatively small, owing to the time of day at which 

 the earthquake occurred— five o'clock in the afternoon — and the damage done 

 was reduced by the fact that there are no large cities within the area of 

 maximum violence ; but in extent and capacity of destruction, as distinguished from 



