Biscuits: Place flour in a large bowl and make a well in the flour. Pour
starter into the well and add all other ingredients. Stir until mixture no longer
picks up flour. Cover and let rise three to four hours, or overnight.
Place dough on floured board and roll to one-half-inch thickness. Cut out
biscuits and place in greased cast-iron Dutch oven. Set by the campfire to rise
for one to two hours. Place hot lid on oven, set oven on coals, and place coals
on lid. Cook until brown (five to eight minutes).
Sourdough Starter: Dissolve yeast in warm water, and then mix all ingredients
in a one-gallon crock. (Do not use a metal container.) Cover with a close-fitting
lid and let the starter rise until light (12 hours in warm weather, longer in
cool weather). Do not let the starter get cold, ever.
After using part of the starter, add one cup warm water, two teaspoons sugar,
and enough flour to mix to the starter's original consistency. Add more
potato occasionally as food for the yeast, but do not add more yeast.
Use starter daily for best results.
Starter improves with age.
Source: Anne Christian, Figure 3 Ranch, Amarillo, Texas