Ken,
I'll add some more to your research this is is show a typicial mill system of that time,with the Indians tribes under treaties
for funds for schools,blacksmiths,Gristmills/sawmills.
After reading this most mills looked like they were somewhat small before the war but had 15-25 ft wheels that water passed over or under with a great amount of water they needed supply ponds to turn the large wheels.
Most early pioneer mills both grist-stones and saw blades it was just a matter of changing the gearing to run either.
So they could be both Saw mills and Grist mills if so built--general infor