Comte de Paris, History of the Civil War in America. Vol. 3.
Henry Coppee , LL.D., Ed.

The streams which traverse this section of country were at this season altogether insignificant. The principal ones, Willoughby Run and Rock Creek, pursue a parallel course from north to south, one west and the other east of Gettysburg, emptying themselves lower down into Marsh Creek. The banks of these two resemble each other. Covered with woods, those of Rock Creek, as its name implies, are bristling with rocks, which, rising as high as one hundred and twenty, and even one hundred and fifty feet, above its bed, have prevented the woods from being cleared. Those of Willoughby Run are not so high nor so steep, and are less wooded. The battlefield is comprised between the right bank of the former and the left bank of the latter. The hills that are met on this ground may be divided into two groups, disposed in analogous fashion, whose formation reveals a geological law which is common to the whole section of this country. Each group forms a combination of three ridges starting from a common point, alike in elevation and abruptness. The central ridge, the highest and longest, follows a southerly direction; another, equally straight, but less elevated, south-south-westward; the third, extending east-south-eastward, is short, and split into two sections, as if, by the general direction in the upheaving of the ground, it had been thwarted in its formation. The starting-point of the first group is a ridge situated one and a quarter miles north-west of Gettysburg, in the direction of Mummasburg, called Oak Hill, on account of the thick forest of oaks which covered it. Its central ridge is about two miles long and very narrow, with considerable elevation for two-thirds of that distance, being throughout interspersed with small woods, farms, and country-houses. Among these habitations there is a Lutheran seminary (which has given it the appellation of Seminary Hill), the belfry of which, located on the culminating-point, overlooks the whole surrounding country. The south-western ridge is, at first, only separated from the one last mentioned by a narrow strip of land which deepens in proportion as they diverge. It borders the course of Willoughby Run. The third consists of several round hillocks which gradually