Fort Simon's being indefensible, Oglethorpe retreated to Frederica. His whole force, exclusive of Indians, amounted to little more than seven hundred men, a force which could only enable him to act on the defensive until the arrival of reinforcements which he still expected from South Carolina. The face of the country was peculiarly favorable to this system of operations. Its thick woods and deep morasses opposed great obstacles to the advance of an invading enemy, not well acquainted with the paths which passed through them. Oglethorpe turned these advantages to the best account. In an attempt made by the Spanish general to pierce these woods in order to reach Frederica, several sharp rencounters took place; in one of which he lost a captain and two lieutenants killed, and above one hundred privates taken prisoners. He then changed his plan of operations; and, abandoning his intention of forcing his way to Frederica by land, called in his parties, kept his men under cover of his cannon, and detached some vessels up the river, with a body of troops on board, to reconnoitre the fort, and draw the attention of the English to that quarter. About this time, an English prisoner escaped from the Spaniards, and informed general Oglethorpe that a difference existed between the troops from Cuba, and those from St. Augustine, which had been carried so far that they encamped in separate places. This intelligence suggested the idea of attacking them while divided; and his perfect knowledge of the woods favoured the hope of surprising one of their encampments. In execution of this design, he drew out the flower of his army, and marched in the night, unobserved, within two miles of the Spanish camp. There, his troops halted, and he advanced, himself, at the head of a select corps, to reconnoitre the situation of the enemy. While he was using the utmost circumspection to obtain the necessary information without being discovered, a French soldier of his party discharged his musket, and ran into the Spanish lines. Discovery defeating every hope of success, the general retreated to Frederica.