Skirmishing in Mississippi--Rumors from Grant's Army.
Bolton's Depot, July, 4,
(via Jackson, 4th.) Our cavalry were skirmishing all day yesterday near Edwards's Depot, with Osterhaus's troops.
Our loss is two killed, and we captured sixteen prisoners.
The enemy are firing a national salute this morning.
Negroes are constantly returning to their masters from Grant's army.
They report that the Yankees expected to make another assault to-day.
The enemy were engaged yesterday in throwing pontoons over the Big Black at Baldwin's Ferry.