Source Unknown - do let me know if you know it.
Dress | c. 1780-85
“The hoop has changed from the square shape of earlier decades to a round profile…”
Well, not really. Pocket hoops show up pretty consistently in the 1780s, and eventually it transitions into a bumroll, but we’re by no means outside of the pannier-type silhouette quite yet. Just not as wide.
Also, please cite your sources! This helps enable folks to do research and helps make the field better.