I found a comprehensive article on a website with illustrations which elaborates on the fashion of both American women and American men in the last part of the 18th century. Here you can find it: http://www.americanrevolution.org/clothing/colonial7.html
To sum up, the Americans obviously tried to steer away from English models and turned to the French. However, the French fashions of that period were somewhat influenced by the simpler, more natural English style in that period. Therefore, American style was directly influenced by France and indirectly by England.
Thus, American women generally wore what European women wore: robes a la polonaise, fitted sleeves, bustles to support the skirt instead of panniers, sashes around the waist, fichus, etc etc.