The nature of the ground threw considerable difficulties in the way of the engineer, which accounts for the exceedingly tortuous nature of the track pursued. It is indeed remarkable that without the aid of accurate levelling instruments, any one could be so fully assured that the requisite fall existed as to venture upon the task of its formation. The workmen in the execution of the design probably drew the water along with them as they proceeded. In one place, (G) they seem to have made too free with the fall, and after proceeding for some distance, (upwards of a furlong) have retraced their steps, and constructed the cutting at a higher level. In crossing the valleys, there is sometimes an unusual loss of fall. This is particularly the case at the third mile (E) where there is a difference in the level of the course, on the opposite side of the slack, of nearly ten feet. This valley is permeated by a streamlet, and to take the water across it at the level previously preserved, a stone aqueduct would have been necessary. Appearances seem to indicate that an easier plan was adopted. A dam being formed across the hanging side of the valley, the water of the course was allowed to deliver itself freely into it, and eventually rising after the manner of a mill-head to the level of the course on the western side, pursued its way as before. That this plan was the result of a change in the design of the architect seems evident, for on the eastern side of the valley a second cutting (E) has been made at a lower level than the other, apparently with the view of leading the water more gradually to the lower point. Unfortunately all traces of the water-course are lost for some distance before approaching the station, so that it cannot be ascertained where it entered it, if it did so at all.