The Legend of Sleepy Hollow: How is the description of setting in paragraph 7 important to the development of the passage’s central theme of America’s changing history?

"I mention this peaceful spot with all possible laud, 8 for it is in such little retired Dutch valleys, found here and there embosomed in the great State of New York, that population, manners, and customs remain fixed, while the great torrent of migration and improvement, which is making such incessant changes in other parts of this restless country, sweeps by them unobserved. They are like those little nooks of still water, which border a rapid stream, where we may see the straw and bubble riding quietly at anchor, or slowly revolving in their mimic harbor, undisturbed by the rush of the passing current. Though many years have elapsed since I trod the drowsy shades of Sleepy Hollow, yet I question whether I should not still find the same trees and the same families vegetating in its sheltered bosom. "