These hills have very few interstices or breaks in them, but are more prominent in some places than others. The Sawmill River and the Sprain Branch occasion an entire separation of the hills above Philipse's from those below, commonly called Valentine's Hills. A strong position might be taken with the Sawmill (by the Widow Babcock's) in front and on the left flank, and this position may be extended from the Sawmill River over the Sprain Branch.

On August 14 the anxiously expected message from de Grasse reached Rochambeau and Washington at Dobbs Ferry. In this important document (brought by the frigate "Concorde" from the West Indies to Newport, and thence forwarded to headquarters) the French admiral announced that he would set sail for Chesapeake Bay on the 3d of August with a fleet of twenty-six ships and with 3,500 land troops, but that his orders would not permit him to remain later than the 15th of October. This announcement, taken in connect inn with the continuing intelligence of the advantages offering in Virginia for decisive operations against Cornwallis, at once settled all doubt regarding the most profitable employment of the allied forces. Without delay Washington resolved to quit his situation in Westchester County and march with the greatest practicable ex-

OPERATIONS

pedition to invest Cornwallis at Yorktown. Meantime, however, he took steps to confirm Sir Henry Clinton's impression that his designs were really against New York. During the three weeks which had elapsed since the grand reconnaissance ofXew York, it was not alone Clinton who felt uneasiness and perplexity at Washington's apparent hesitation. The Americans and French themselves were at a loss to account for it; for not a whisper of the real considerations which were influencing the American commander was permitted to get abroad. The letters of the Abbe Robin, a priest attached to Rochambeau's army, reflect the prevailing uncertainty and speculation.