Thomas Brown had operated in this region for three years, with a highly trained and disciplined force, and he and his men knew every trail and stream. His information about the planned invasion of Florida had been shared between the governor and General Prevost, and there was a struggle over who would command and ultimately receive credit for another expected expulsion of American forces. Most of the British regular troops stayed near St. Augustine to guarantee its defense while others were sent to strengthen Fort Tonyn, where the Americans were first to be confronted. Without specific orders to the contrary, Brown decided to ignore the decision of his superiors to yield to the Americans while they were still in Georgia. The Rangers, using tactics of the natives, harassed the invaders at every opportunity as they moved through the swamps and pine forests and eventually crossed the St. Marys into Florida.

Brown followed General Prevost’s orders that Fort Tonyn be burned and abandoned, leaving the American forces with a hollow victory, and then placed his three hundred Rangers in direct line of the rebel’s advance. The governor had earlier requested that Brown’s forces be given supplies and military support, pointing out that the Rangers had been the ones who had gathered the available provisions. General Prevost refused, unless Brown and the Rangers were put under the direct military command of his son, Major James Mark Prevost. Tonyn, having exhausted all his authority, asked Brown to “waive every punctilio” and agree to serve under regular military officers. Without leaving his post, Brown submitted his resignation, explaining that this was a severe censure upon his service as an officer and a gentleman and that he could not betray commitments to his Rangers and “serve under every British subaltern.” He reminded the governor that the king had personally approved the independent status of the Rangers. Tonyn forwarded Brown’s response to General Sir Henry Clinton, who was sure to rule against Brown. Not receiving any supplies from the British main force, Brown issued instructions to his men on how to subsist on the leaf buds of palmettos, which the Rangers soon said were “better than cabbage.”

Major Prevost deployed his men fourteen miles farther south of Brown on Alligator Creek, a site well known to the Rangers. Never having been welcomed into Fort Tonyn, the Rangers had used this crossing point as a campsite, and had deepened some finger lakes to enclose a raised mound of earth that the men named Brown’s Battery. Major Prevost now sent word for the Rangers to retreat and join his forces, but Brown dispatched only half of his men to Alligator Creek to improve its defenses and led the rest to harass the invading force on its flanks and rear.

After the Americans discovered the charred remains of Fort Tonyn, Elijah Clarke announced to his men, “This reminds me of Burnfoot Brown’s foot!”