A unique feature of some of the hats during the 1830s was a steep crown. Look at the second hat from the upper left in the fashion plate below.
|1833 fashion plate from Wikipedia Comons|
The bonnets with the steep crown were designed to accommodate a popular hairstyle called the Apollo's knot:
|Apollo's Knot hairstyle 1830s|
The hair was worn all curly at the sides. A top knot like this would be more for evening wear. During the day the hair might be worn in a bun at the back--like Lady Jane's below. The other bonnets would work better for her type of styling. (Isn't she a beauty?)
|Lady Jane Elizabeth Digby as painted by Stieler 1831|
Regardless of the bonnet's shape, you could be sure that it would be festooned with ribbons, lace, flowers, or bows.