TWENTY-NINTH ANNUAL MEETING. 127 
old gulf salt was deposited in large amounts, and forms to-day an important ad- 
dition to the mineral wealth of the state. No salt is now found close to the gyp- 
sum, and if it did exist it has been removed by solution. The irregular upper 
surface of the gypsum shows that there has been solution in some places where 
large quantities of gypsum rock have been carried away. 
The swamp deposits of earthy gypsum have probably been formed by deposits 
from springs, aided by wash from the hillsides, and they are recent in age. 
The southern gypsum was deposited in a shallow gulf cut off not far from the 
close of the Permian time. As in the northern gulf, a salt deposit occurs to the 
southwest in the salt-plains district; but no trace is found near the gypsum. 
THE STUDY OF NATURAL PALIMPSESTS. 
By G. P. Grimsuey, Topeka, Kan. Read (by title) before the Academy January 2, 1897. 
Paleontology has revealed a long life-history from Cambrian time to the pres- 
ent, and has vainly attempted to read the obscure pages of earlier history of 
Archean time. Baffled at every turn, the search was abandoned; but a new 
science has boldly entered the field, and the mysterious pages furnish a history 
for the petrographer, which in interest rivals that of the paleontologist. 
This record is not written in fossil letters, but in mineral characters, which so 
long have been meaningless geoglyphics. In making the so-called prehistoric 
record, nature has been economical in materials and,in space. She has erased 
some portions of the ancient record with the cleansing force of fire, rewriting on 
the same tablets of stone the records of new conditions. 
The discovery that many of the records of ancient historical time were written 
on erased parchments of an earlier day, and that a careful investigation would 
reveal many of the first records, was a historical triumph. The students of 
ancient languages have enriched the world by their painstaking search through 
old literary palimpsests. In the past decade the students of nature have discov- 
ered the existence of natural palimpsests, and they are now endeavoring to 
read the imperfectly erased records of the past, and thus add new chapters to 
the history of the earth. To the process of erasure and rewriting these investi- 
gators have given the name metamorphism; and the natural palimpsests are 
called metamorphic rocks. ji 
The studies of biologists have shown that throughout organic nature there is 
a most delicate adjustment to environment. The researches of petrographers have 
shown that in the inorganic world minerals are so delicately adjusted to surround- 
ing conditions that changes in the latter are recorded by variations in the miner- 
als. The recognition of this fact in recent years is the foundation of the new 
knowledge concerning the Archzan period. 
According to the Wernerian theory of the last century, crystalline rocks were 
deposited as chemical precipitates from a primeval heated ocean before life ex- 
isted. They were produced at their origin as they exist to-day. Near the close 
of the century, Hutton found granite dikes penetrating other rocks, thus proving 
an igneous origin. He then advanced farther and formed the interminable cycle, 
stating that rocks were decomposed by atmospheric action, the detritus accumu- 
lated at the bottom of the sea, where under the pressure and heat it was rendered 
crystalline, and later elevated to pass through the same series of changes without 
trace of beginning or prospect of end. The theory of the transformation of rocks 
under heat and pressure originated at this time in this rudimentary form in Scot- 
