CHAPTER V. 
ORIGIN OF GYPSUM. 
General Theories of Origin. 
In order to explain the conditions given and to account for 
the origin of the gypsum deposits of Kansas, it will be well first 
to outline the different theories advanced on this subject. 
DEPOSITION FROM SEA WATER. 
Gypsum has been deposited by the evaporation of sea water in 
enclosed lakes or bays which have been cut off from the ocean. 
Sea water, according to the analyses in the Challenger Reports, 
contains 3% per cent. of mineral matter. When this is analyzed 
the following salts are found : 
Chioriderotsodimmey(commonysallii]) aera eae 17.758 
Chiloriderofimacnesiun aaa een ere ee La ear aca 10.878 
Sulphate of Ma eme stays yay sels eee Ome ea epee ee oa hao 
Sulplaitevotalim en ((esyjoS una) enews ee erie ae eee 3.600 
Sulphaterohpotassiumagie cea eee ee eran ans ere ae 2.465 
@arbonate of Time: social oar Oe en ae 0.345 
Bromidetotimaonesivimarenrnie nc nn een cen een ee 0.217 
A Woe: Damrey ar Mente a eM itna cranial Use ean asta as aL ie 100. 
When such a body of water is cut off and evaporated, the 
gypsum is deposited after thirty-seven per cent. of water is re- 
moved, and common salt only after the removal of ninety-three 
per cent. The normal order would be a deposit of gypsum and 
then a much heavier deposit of salt. But as ninety-three per 
cent. of the water must be evaporated before the salt would be 
thrown down, the evaporation might go far enough for the 
deposition of gypsum, but not far enough for salt; or the salt 
might be deposited, and subsequently removed by solution. 
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