IOWA ACADEMY OF SCIENCES. 
137 
settling is very translucent. It adheres to the tongue and 
has a slightly styptic taste, probably due to a little dissolved 
alum as there are some alum springs near by. It has a 
slightly acid reaction to litmus. It absorbs the coloring 
matter from ink and removes the grease from cloth. 1 do 
not have access to a very large amount of mineralogical 
literature, but the analyses that have been found compare 
with it very unfavorably. I believe it must be one of the 
purest products known. The deposit is believed to be fairly 
extensive. 
