290 NATURAL SCIENCE [November 1898 
subject synthetically ; he has shown that the structure of the world 
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 produce the chains of fold- 
mountains. Suess’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 tetra- 
hedron, 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, while the land masses 
oceur 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 litho- 
sphere, and the existence of impassive blocks of old strata which 
have moulded the latter movements. ‘The lines of the old fold- 
mountains of the Hercynian system may have been tetrahedrally 
arranged, but 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 we 
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.” 
TOXODON 
THE important serial publications of the Museum of La Plata, Argen- 
tina, contain some of the most valuable contributions to natural 
science which have been made during the last decade. We have 
had frequent occasion to refer to them, and to the vast store of 
unique specimens which the energy and genius of Dr F. P. Moreno 
have accumulated in the comparatively new capital of the State of 
Buenos Aires. The Revista and Anales, however, contain only 
