Page:Historic highways of America (Volume 10).djvu/48

48 Cumberland and Brownsville on the new route.

"In the gradation of the surface of the route (which became necessary) is ascertained the comparative elevation and depression of different points on the route, and taking a point ten feet above the surface of low water in the Potomac river at Cumberland, as the horizon, the most prominent points are found to be elevated as follows, viz.: