Should be spelled saleratus. Saleratus is a chemical compound (potassium carbonate) which naturally weeps from the ground as mineral-bearing water evaporates. Coming from Latin roots, sal aeratus means aerated salt, referring to its ability to produce carbon dioxide when mixed with another acidic food element such as vinegar or tartaric acid (cream of tartar). It is used instead of soda to make biscuits. Pioneers on the trail often gathered saleratus when they found it, for example near Independence Rock in Wyoming. It is also reported to occur on the shores of the Great Salt Lake. I believe I have seen some such deposits in the past.