If you visit St. Croix Parish GenWeb at
http://www.rootsweb.com/~nbstcroi/

you'll find Henry Simpson and an email address for Bill Romanski who has gathered quite a bit of data on the family.
The link to his website is broken, but his email address is current.

You might also visit the other parishes in Charlotte County as well, as Simpson is a popular name.

http://www.rootsweb.com/~nbcharlo/parishes.htm#parish