84 PROCEEDINGS 0¥ THE CHICAGO MEETING 



done vuKkn- the direction of H. A. Buehler, of the Missouri Bureau of Geology 

 and Mines. 



In parts of the Missouri Valley the Pennsylvanian rocks, in which the writer 

 was principally interested, were found to be deeply buried by glacial drift, 

 while in others only thin remnants of drift were found above the rocks form- 

 ing the valley sides, usually high above the level of the floodplain. This con- 

 dition prevails from Forest City to Kansas City. 



Preglacial Platte Valley 



The master preglacial stream of northern Missouri seems to have been a 

 stream that entered the State at the northwest corner, flowed southeast, and 

 joined what is now the Missouri at or near the mouth of Grand River. It 

 united at this point with what was a continuation of Kansas River, and the 

 stream thus formed followed approximately the course of the Missouri to its 

 mouth. 



That the northern stream was the continuation of the Platte (of Nebraska) 

 seems highly probable. The first writer, so far as known, to suggest a buried 

 valley under the Missouri was Captain Theo. A. Bingham. In his report" on 

 the results of borings in the Missouri Valley he calls attention to the dis- 

 covery, near Nebraska City, Nebraska, of a buried valley in which bedrock is 

 60 to 75 feet lower than it is a short distance to the north or south, or 165 to 

 175 feet below the level of the floodplain. This valley lies at right angles to 

 that of the Missouri (about south 80 degrees east) and is filled with "very 

 hard, tenaceous, drab-colored clay mixed with angular fragments of stone, gen- 

 erally of lime, though in one observed instance (boring number 23) of red 

 quartzite, the prevailing boulder material of the northern glaciers." The sug- 

 gestion is made that the Platte left its present valley at the abrupt turn about 

 20 miles above its mouth (at Southbend) and plowed southeast. The writer 

 has not had the opportunity of testing this theory in the field, and therefore 

 can offer no conclusive proof as to its correctness. 



J. E. Todd^ has suggested that the Platte may have crossed northern Mis- 

 souri, following the present course of Grand Ri^•er most of the distance. In 

 this supposition he was only partially correct. Assuming the Platte crossed 

 the present Missouri Valley at the place described by Bingham, it entered Mis- 

 souri in Atchison County. The widening of Nodaway River between Quitman 

 and Burlington Junction is due to the more rapid lateral erosion in the soft 

 material of the buried valley. Maryville is situated over it, as shown by a 

 boring there which passed through 170 feet of drift, although drilled down on 

 the floodplain of One Hundred and Two River. The Wabash Railroad marks 

 the location of the old valley as far east as Darlington. Grand River here 

 bends to the south and occupies a rock-walled postglacial valley, Avhereas the 

 buried valley continues to the east, crossing the southern part of Harrison 

 County and the northern part of Grundy. Entering Linn County, it turns 

 south and again coincides with Grand River from Fountain Grove to its mouth. 



- Report on borings in the Missouri River Valley. Missouri River Commission report, 

 year ending .Tune 30, 1800, published as Appendix XX to the 'report of the Chief of 

 Engineers, U. S. Army, pt. 4. 1890, pp. 3.375-.3300. 



= Science, new series, vol. xxxix, no. 909, February 20, 1014, pp. 263-274. 



