Common hat shapes during the American Civil War era.
There are 2 main componants to a hat from this era: the crown and the brim. Both thd crown and brim were particularly shaped to reflect the styles of the time.
When selecting hat for an 1860-1865 impression, please keep in mind the situation you are in as well as your impression. In many cases hats had specific purposes and places. These include those for the seaside, watercures, the garden*, and recreation. There are seperate posts for these. I welcome you to explore these. There are also hats appropriate to those of poorer situations, institutionalized or previously so situations, and blockaded situations. (*note: a garden hat is different than one for gardening.)
This next style is called a “Mousquetaire” hat or a “Postilion” hat.
Mousquetaire hats have tapered crowns that rise about four to five inches, not quite double the height of other fashion hats of the early 1860s. The brim is shaped, with a curve dipping front and back. This brim is narrow, only a few inches wide. The decorations are primarily at the center front, reaching the height of the crown. A ribbon may or may not circle the crown with a bow or arrangement in the back.
Additional variations (I have yet to make graphics for):
- Smaller hats including Torque and porkpie
If I Had My Own Blue Box: 
Thanks for the informative post. I am unable to read the info on variation D as it does not appear clearly like the others do on either my phone or my desktop computer. Otherwise, a very useful post!