3i6 Tlic Amcrica?i Geologist. May, i899 
found not to enter Arkansas at any point. A narrow belt in 
eastern Oklahoma is also made up largely of these same strata. 
Recapitulation. 
From the consideration of the foregoing description of the 
section displayed by the gorge of the Missouri river several 
conclusions of interest may be deduced: 
1. The title of Upper Coal Measures is inappropriate for 
the series of rocks, commonly called by that name, though sev- 
eral thin seams of coal are known to occur in the formation. 
Had the series been even partially understood early in the per- 
iod when it was first investigated geologically the name of Coal 
Measures would probably never have been suggested. 
2. In their most characteristic facies the Missourian rocks 
are essentially marine beds. 
3. The Missouri River section may be taken as the typical 
one of the Missourian series. The stream cuts through the 
entire formation exposing in its full development every sub- 
division. 
4. The Missourian is a well defined series. It contrasts 
strongly with the other series of the Carboniferous of the re- 
gion in all its topographical, lithological, stratigraphical, and 
biological characters. 
5. The subdivisions here recognized have a wide geo- 
graphic extent. 
6. The Missouri River section provides a standard for 
comparison of the formations for the whole Western Interior 
region. Uniformity in description may now be considered as 
prevailing in five states and two territories and a comparison of 
results may be readily made. 
