There is a French Creek chert from the Custer area. Perhaps if you can locate french creek.....?
Also there is a nice red material similar to Hixton called Battle Mountain Chert, that's in Fall River County out there......Find battle mtn.
In the same county, there is a White Horse Creek chert as well........ Maybe locate White Horse Creek.
Fall River co is Hot Springs and south
Sheperdess. a past forum poster is in Sturgis, I know she hunts some right around there. I can sure get you in touch with her. She just helped out a friend of mine yesterday with a bunch of petrified wood she and her sisters have for sale. Some nice stuff too.
On your way back, I can show you examples.