M'GEE — NOTES ON THE GEOLOGY OF MACON CO., MO. 309 



The three phiteaus, are generally prairie, but their crenulate 

 margins and the subordinate valleys of the short tributaries are 

 commonly wooded with oak and other hard-wood trees, frequent- 

 ly of stunted growth ; while the valleys of the two rivers by 

 which they are divided generally support a more luxuriant and 

 varied forest growth. 



The principal waterways of the tract — Salt river and East 

 Fork — occui)y the valleys by which the low plateaus are sepa- 

 rated. In many respects these valleys are similar: each is dis- 

 proportionately large as compared to the stream ; each is a broad 

 flat-bottomed trough bounded by steep, even precipitous, bluffs, 

 which commonly assume the forms of spurs and salients separa- 

 ted by narrow, sharply incised ravines, or by the broader valleys 

 of the secondaries ; through each the stream flows in a narrow 

 channel 15 or 20 feet deep, which meanders from side to side of 

 the valley in closely recurved loops, as does the Lower Mississippi 

 on a larger scale ; each most frequently approaches the western 

 side of the valley, sometimes exposing there low precipices of the 

 stratified rocks ; each is lined by alluvium to and generally below 

 the channel bottom ; the floor of each is diversified by crescentic 

 ponds and bayous, and also by the deeply cut channels of the 

 secondaries and the runnels extending from the lateral ravines ; 

 and each valley bottom has a slope in the direction of stream-flow 

 little greater than the gentle southward slope of the plain in 

 which it has been excavated. The Salt river valley ranges from 

 a quarter to fu'ly three-quarters of a mile in width, averaging 

 perhaps half a mile, and its depth is 50 or 60 feet. The East 

 Fork valley ranges from a quarter of a mile to over a mile wide, 

 averaging perhaps three-quarters of a mile, and its depth proba- 

 bly lies between 90 and 100 feet. Most of the secondaries are 

 small, have high declivity, and flow in narrow V-shaped ravines, 

 frequently bifurcating and forming widely branching dendritic 

 systems sharply incised in the plateaus ; but the more important 

 — eg. Long creek and Claybank creek — meander in deep chan- 

 nels through flat-bottomed valleys analogous to those of the 

 rivers. 



The leading characteristic of the topography is the combina- 

 tion of level plain and steep slope : a profile transverse to the 



