Large parts of the German Highlands are made up of folded Paleozoic and crystalline rocks, forming the Variscian Mountains of Sucss. Except for their shorter length, these old ranges surprisingly resemble the Appalachian Mountains, both in their material and in their structural behavior. Latest of all the rocks, as in New England and the southern Appalachians, there appears in the core of the German mountains a large number of granitic rocks. While they were once generally supposed to be large batholithic, bottomless masses, that had risen upward by magmatic stoping, which cut the folded, sedimentary strata unconformably and which were more or less independent of the associated country rock, it has lately been shown by Professor Hans Cloos, of the University of Breslau, Germany, and his associates that at least some of the granites have a different history. We know now that their material, while rising, was affected by . . .