Journal of Surgeon Alfred L. Castleman.

10th.–Returned to the main road this morning, followed it for a short distance, then, turned to the right, towards Frederick, by the way of Sugar Loaf Mountain. For two days we have been marching in full view of the Alleghany spurs, and to-night sleep within three miles of the foot of the Sugar Loaf. These mountains present a spectacle both grand and sublime, when viewed at a distance. ‘Tis worth a half a life of travel to see them. The men, to-day, have been forced beyond their power to endure, and very many of them have fallen out. Indeed, some regiments are reduced, to-night, to less than half the numbers with which they started in the morning. Rumors vague as vast, in reference to the strength of the enemy in Maryland, meet us to-day. They are variously estimated by those who have seen them, at from thirty thousand to two hundred and fifty thousand–a great margin, truly. We meet to-day, occasionally, our wounded cavalry men, coming in from successful skirmishing with the enemy’s outposts about Poolesville and Sugar Loaf; but they have fallen in with no large body of troops.