14 University Geological Survey of Kansas. 
At the close of Coal Measure time it seems that the greater 
part of the eastern half of the North American continent ex- 
isted as dry land, with considerable portions of the great west 
also above ocean water. ‘This left a great arm of the ocean ex- 
tending north and south from the Gulf of Mexico to the Arctic 
Ocean, covering the territory now occupied by the western part 
of Texas, Indian Territory, Kansas, Nebraska and the Dakotas, 
and the eastern part of New Mexico, Colorado, Wyoming, and 
similarly situated portions of British Columbia. 
The development of the continent throughout former periods 
of geologic time had, in the main, been a progressive one, so 
that by the close of each time period a new portion of dry land 
had been added to the young continent, continuously making 
itlarger. At one time the western coast of the continent was 
near the southeast part of the state, with the land area lying to 
the east. Progressively the land area was elevated and the ocean 
was driven back by the westward migration of the coastal line, 
a progress continuous throughout Coal Measure time, as has 
been fully explained in Volume III of this series of reports. 
Little by little the land area increased in size by the westward 
progression of the shore until, at the close of the Coal Measure 
period, the conditions above mentioned were devoloped. 
Throughout the time just referred to sedimentation was a 
continuous process, forming the heavy Coal Measure shales 
and limestones which underlie the Permian, and which aggre- 
gate in Kansas about 3,500 feet in thickness. Step by step our 
state was built up by the slow but persistent accumulation of 
sediments, and the continuous westward migration of the ocean 
shore. Bed after bed was formed in this way, generally reach- 
ing eastward to the then coastal line and extending westward for 
unknown distances. Hach succeeding bed, therefore, overlies 
the preceding ones, but its eastern limit is further west than 
that of those below it. 
The same land movements which drove the ocean waters west- 
ward throughout Coal Measure time continued throughout the 
Permian and later times until finally the whole of the great ex- 
panse of ocean water, which may be called the ‘‘ Mediterranean 
