GENERAL CONFIGURATION. 77

is generally considered to be, granite, which extends from those mountains, and forms the prevailing basis, With some exceptions, however, of all the countries lying between them and the Atlantic, and north of the river Hudson. These territories are also con-

sidered to have been frequently convulsed by earth- quakes, While those west of the Alleghanies have remained undisturbed.

Limestone, generally in horizontal strata, prevails to the westward of the Alleghany chain, as far as the St Lawrence and the lakes. On the north of the St Lawrence, and throughout Labrador, granite predominates ; and Sir Alexander M‘Kenzie remarks, in his travels, that the great lakes of North America are in a line of contact between vast chains of granite and limestone.

Volney observes, that the granitic range of the Alleghany chain may be said to terminate southward, (or, more properly, loses itself to observation,) at lVest Point, river Hudson, on the opposite side of which sandstone commences, and prevails from the Kaats- kill Mountains to the angle of Georgia.

Those vast inland seas, the great lakes, form, «with the St Lawrence and other magnificent rivers, most gigantic features in the geography of North America ; to which we may also add the Gulf of St Lawrence—— a Mediterranean—bounded by our territories; the Bay of Fundy, with its extraordinary tides; and the icy bay of Hudson, which divides rocky, inhospitable Labrador from the north-western, or frozen regions of the transatlantic hemisphere.