326 GEOLOGIGAL SKETCHES Of 



Geological Sketches of the Mississippi Valley, by 

 Edwin James. Read Oct. 8, 1822. 



We offer a hasty sketch of the Geology of the Mis- 

 sissippi Valley, in anticipation of a more detailed ac- 

 count, which will be given in the Journal of the Ex- 

 ploring Expedition, about to be published in this city. 

 In the accompanying sections, delineated by Major 

 Long, it will be perceived little attention has been 

 paid to the horizontal scale. Wishing to exhibit, in 

 a small compass, the outline of our idea of the struc- 

 ture of different groups of mountains, some wide aud 

 uninteresting plains as that between 5° and 12° W. 

 in the northern, and that between 11° and 13° in 

 the southern section, have been omitted. Particular 

 attention has been bestowed in adaptiug the delinea- 

 tions to the scale of elevation, according to such es- 

 timates as we have had the means of making. 



The inclination indicated by the lines between the 

 formations is not to be considered applicable to all 

 the strata constituting those formations ; as, in the in- 

 stance of the coal in the southern section of the Alle- 

 ghanies, the strata of sandstone and bituminous slate 

 are nearly horizontal, but they occupy the several 

 stages of elevation indicated by the inclined line in 

 the section. The lines, therefore, should be consi- 

 dered as indicating the position of formations rather 

 than the inclination of strata. 



In the southern section of the Ozark mountains, 

 the inclination of the strata is usually towards the 

 south or south-east, but more irregular in direction 

 than in the Alleghanies. 



