RICHMOND, December 15, 1780. SIR,--I had the honor of writing to your Excellency on the subject of an expedition contemplated by this State, against the British post at Detroit, and of receiving your answer of October the 10th. Since the date of my letter, the face of things has so far changed, as to leave it no longer optional in us to attempt or decline the expedition, but compels us to decide in the affirmative, and to begin our preparations immediately. The army the enemy at present have in the south, the reinforcements still expected there, and their determination to direct their future exertions to that quarter, are not unknown to you. The regular force, proposed on our part to counteract those exertions, is such, either from the real or supposed inability of this State, as by no means to allow a hope that it may be effectual. It is, therefore, to be expected that the scene of war will either be within our country, or very nearly advanced to it; and that our principal dependence is to be on militia, for which reason it becomes incumbent to keep as great a proportion of our people as possible free to act in that quarter. In the meantime, a combination is forming in the westward, which, if not diverted, will call thither a principal and most valuable part of our militia. From intelligence received, we have reason to expect that a confederacy of British and Indians, to the amount of two thousand men, is formed for the purpose of spreading destruction and dismay through the whole extent of our frontier in the ensuing spring. Should this take place, we shall certainly lose in the South all aids of militia beyond the Blue Ridge, besides the inhabitants who must fall a sacrifice in the course of the savage irruptions.