This was a basic tension on the frontier, in these frontier settlements.

这是边境上的基本紧张局势，在这些边境定居点。

The Florida swamps were a basis for Indian marauders who periodically swept into the frontier settlements, and hiding places for runaway slaves.

佛罗里达州的沼泽地是印第安掠夺者的据点，他们定期闯入边境定居点，也是逃亡奴隶的藏身之处。