346 J. LeConte—Formation of the 
to wrinkle, 1. e., to bend into alternate convex and concave arches, 
which form respectively the continents and sea-bottoms. The 
Continents and sea-bottoms.—If we regard the earth as consist- 
ing of a solid crust sustained as a floating body upon a liquid, 
the least reflection suffices to convince us that the greater inequalt- 
ties of the surface cannot be produced by alternate convex and con- 
cave bendings of the crust like those shown in fig. 1, in which @ 
is the continental and } the oceanic crust, and J/ the sea level. 
No such arch as that producing a continent 3000 to 6000 miles 
across), should sustain itself The arch a would break < 
* Phil. Trans., May, 1862. 
