386 The American Geologist. December, 1894 
Ozarks have remained above water. The accumulations of 
the St. Louis and Chester limestones were greater along the 
Mississippi, and thin out westwardly. The later Chester or 
Kaskaskia limestone was represented only by a sandstone in 
northern and southwestern Missouri. At this time there was 
a marked change in fauna and flora, as well as in continental 
area. The deep ocean floor, east, north and west of the 
Ozarks, which had been so long receiving deep sea deposits 
sufficiently to be part land, part water, rose with a surface 
nearly flat, over which were lakes and vast swamps, beginning 
to support a rare and luxuriant vegetable growth, the fore- 
runner of the coal period. The leaves and older trees fell and 
accumulated in the peaty swamps and in time were covered 
by the overflowing seas, leaving silt and sediment. Soils were 
formed ; forests grew and matured, and lycopods and ferns* 
left their debris to be again covered up. At one time the 
surface would sink so much that the overflowing sea covered 
the older beds with accumulations of limestone. In this way 
a number of ancient forest beds with their vegetable growth 
were buried. Each of the beds of decaying vegetation was 
converted to coal ; the same vegetation in the presence of the 
atmosphere would form humus. That there was probably a 
great deal of carbonic acid in the atmosphere during the coal 
period is believed; also that this was absorbed or withdrawn 
by the luxuriant plant growth. While these deposits were 
being formed, a large portion of the Mississippi valley was 
sinking. Still the Ozarks kept their everlasting hills above 
the waters, while Kentucky, Indiana, Illinois, Iowa, northern 
Missouri, Arkansas and Texas were nearly covered by coal 
swamps, over which the sea would occasionally flow. 
During the formation of the coal in the Appalachians and 
the Mississippi valley, and while the country in general was 
being subjected to alternate depression and elevation, the 
present Rocky mountain region remained for the most part 
under a deep sea. The coal of the west is of more recent age. 
In that region, during the time of the Upper Carboniferous 
period, limestones were chiefly formed in the deep seas. We 
*[Note. At presenl we may have about 15 species of living ferns in 
Missouri. In Henry county over 40 species have been obtained from 
tin- shales overlying the coaj beds, all pressed and beautifully preserved 
in nature's herbarium.] 
