ARTHUR WINSLOW — THE MISSOURI COAL MEASURES. 113 



( >n the basis of the figures above given we'have an elevation of about 900 feet for 

 the floor of the Coal Measures at the margin near Sedalia, and in the extreme north- 

 wesl the position of the floor is about 700 feet below sea level. Consequently the 

 present slope of this floor is 1,600 feet in a distance of some 150 miles, which is equiva- 

 lent to about 10 feet per mile, or about one-tenth of one degree of slope, which is 

 almost horizontal. The elevation of the surface of Maryvilleis about L,200 feet : 

 so that the thickness of the Coal .Measure rocks there found abovethe level of Sedalia 

 is only about 300 feet; thus the regional elevation which finally lifted the Coal 

 Measures above the water level was not necessarily much greater in the interior 

 than along the margin. 



Lithology and Stratigraphy. 



The rocks of the ( !oal Measures consist almost wholly of sandstones, shales, lime- 

 stones, and coals. 



The sandstones are of white, drab, yellow and reddish colors, are generally line 

 grained and friable, and are often filled with specks of carbon and with impres- 

 sions of leaves and stems, especially along the stratification plains ; mica is almost 

 always present. The sandstones are most abundant and prominent in the eastern 

 and marginal area of the Coal Measures, and they there constitute a considerable 

 portion of the section. In the interior or central area they are not prominent 

 members, though arenaceous shale is abundant, and it is frequently difficult to say 

 whether such material should properly be classed as a shale or as a sandstone. 



The shales are argillaceous, bituminous, arenaceous, or calcareous, and frequently 

 grade by almost imperceptible degrees into sandstones or limestones; they are id' 

 black, drab, gray and red colors. The shales preponderate by tar over either of 

 the other classes of rock, are widely distributed, and are about equally prominent 

 in all sections of the ( 'oal Measures. 



The limestones are sometimes in massive beds, three ami even more feet in 

 thickness, are occasionally concretionary and in nodular forms, are sometimes 

 laminated with uneven bedding planes, but are almost always of a fine compact 

 texture ; they are of drab color, ami are readily distinguished from the white, coarse- 

 grained, semi-crystalline limestone of the lower Carboniferous. The limestones 

 are least abundant over the extreme marginal area, and become more frequenl ami 

 thicker toward the interior ; in the northwestern portion of the state they occur 

 in beds aggregating twenty or more feel in thickness. Lime is here very abun- 

 dantly represented in all the rocks; many of the shales, even the black bituminous 

 layers, being decidedly calcareous. As with t he shales and sandstones, SO with the 

 shales and limestones, it is often impossible to class a rock positively as a lime- 

 stone or as a shale. 



The coals are all bituminous, with the exception of certain local deposits which 

 approach cannel coal. The beds range in thickness from one inch to about five feet. 

 They a:.- generally soft ami pyritiferous, with selenite almost alwaj s presenl in thin 

 scales along the joint planes. They are almosl in\ ariably underlain bj clay, which 

 sometimes contains stigmaria casts. They are generally immediatelj overlain by 

 black shales, frequently fissile, or by a gray or drab claj -hale. In this -hale leaf 

 impressions are found in places, but the localities are few where such are abun- 

 dant. Sometimes sandstone rests directlj upon the coal, or a limestone cap-rook 

 is hareh separated from it by a few inches of claj or -hale, but such instances are 



exceptional. The cnal beds are mosl abundant and are thicke-t over the marginal 



\ \ Bi i -.■■ \ i Vol ::. 1891 



