Calash Bonnet

From the seller:

WOMANS ANTIQUE HAND STITCHED WIRE FORMED COLLAPSIBLE SILK BONNET 1800`s WELL WORN SMALL WORM HOLES AND STAINING BUT NICE CONDITION FOR AGE SEE PHOTOS MEASURES 13 1/2" DIA. TOP FRONT TO BACK OPEN MEASURES 12" PLEASE ASK QUESTIONS BUYER TO PAY 25.00 SHIPPING AND INSURANCE & DELIVERY CONFIRMATION. IF I AM OVER ON SHIPPING I WILL REFUND THE DIFFERENCE. PLEASE REFER TO: collectorbooks.com/pdf/items/7757.pdf THIS WEB SITE GIVES MORE INFORMATION ABOUT THE BONNET. THANKS FOR YOUR INTEREST

From Me:

I think this Calash is late 18th century. Here are some similar ones in museums dated to the 1770's.

The Met's Calash
MFA's Calash

However, it's really hard to tell because this style was revived by the Romantic era.
Met's 1840's Calash

I'm going with the earlier date because that's when it was first fashionable.