600 KANSAS CITY REVIEW OF SCIENCE. 
Stone and is very abundantly interstratified with the rocks of Missouri. Although 
much of it is flint-like and is even called flint, still it is scarcely proper to apply 
the term " flint" to our Missouri chert beds, but they may sometimes be termed 
hornstone. 
The upper carboniferous incloses chert of different colors and varieties. At 
Kansas City and other places where the same strata occur, we find beds of black 
chert and also of light brown chert. Some of the beds being quite siHcious, 
inclose some pretty fossils whose composition is often a milky looking chalcedony. 
The lower carboniferous includes many chert beds. The gray Keokuk 
limestone beds include numerous white chert concretions. The upper Burling- 
ton beds consist near the top of seventeen to twenty feet of alternate beds of 
white chert and red clay. The Chouteau beds occasionally inclose concretions 
of white and bluish chert. 
The Magnesian limestone series of southeast and southern Missouri abound 
in concretionary chert beds which {in the second magnesian limestone) are bed- 
ded in shaly strata separating them from the hmestones. In the third magnesian 
limestone occur some thick chert deposits which sometimes can be traced many 
miles. Such beds I have found along the Osage and Gasconade. These are 
generally of a white or gray color, sometimes a grayish blue and rarely a flesh 
color : they are sometimes beautifully banded forming coarse agates. The con- 
cretionary chert beds often assume curious forms. The concretionary chert beds 
or beds of concretions generally occur along a well defined line either connected 
or separated from each other but arranged parallel to the inclosing limestone 
strata. These lower magnesian limestone beds also inclose many pretty oolitic 
chert beds, the Oohtes are often as small as the roe of a herring. 
We also often find very pretty round concretions which when broken show 
that they were formed in parallel concretionary bands, the bands sometimes are of 
different shades of color. The interior, though generally solid sometimes contains 
clay. Our fossil woods are generally of some variety of chert, hornstone or 
chalcedony. Some from Colorado and Idaho are a variety of opal. Beautiful 
chalcedonic wood is found in Colorado. Moss agate in western Kansas and Col- 
orado. The fossil silicious wood of the carboniferous is generally of a black 
color, which is due to the presence of carbon. This is also further traversed by 
chalcedonic veins, and small cavities are sometimes lined with minute crystals of 
quartz. 
The cretaceous formation in England incloses rounded nodular masses of 
chert of various sizes and shapes and colors, white and black. These are some- 
times formed in concretionary bands of black and white, and exhibit markings 
derived from organic bodies. 
When flint is calcined it becomes white, hence its color is attributed to 
organic matter derived from inclosed fossils. Quartz has been formed by organic 
agency, for example, from spiculse of sponges or from plants ; it is also formed 
by the agency of water as flint concretions, or by plutonic agency. 
Potter's clay is chiefly composed of silica. 
