532 J. E. TODD — PLEISTOCENE PROBLEMS IN MISSOURI. 



exposition of the facts which I have been able to discover in about three 

 months' field work in connection with the Missouri Geological Survey. 

 I regret that I could not bring the work nearer completion, but as I shall 

 not, at least for some time, be able to carry it farther, it seems best to 

 offer this report of progress for consideration, comparison and criticism. 

 As is well known, the field is not a new one. Years since, various 

 valuable notes were published in the earlier state reports on the Quater- 

 nary formations. I have been pleased to find such statements uniformly 

 reliable, so far as they go. Their deficiencies to a later student arise 

 mainly from two causes. The older formations in early days were con- 

 sidered much the more important and interesting, while later formations 

 were of little significance ; and again, owing to imperfect views, forma- 

 tions of widely difi'erent origin were sometimes associated in the same 

 definition. For example, Professor Sw^allow, on page 77 of the Second 

 Annual Report, states that " the bowlder formation abounds in all parts of 

 the state north of the Missouri, and exists in small quantities as far south 

 as the Osage and Meramec." In this he includes with the northern glacial 

 drift what Broadhead later and more correctly calls " local drift," and 

 which has since been shown to be in part as old as the Carboniferous. 

 Broadhead'S statement that the drift is limited by the bluff's on the south 

 bank of the Missouri is, I find, with a very few exceptions, correct. 



The Preglacial Formations. 

 general geologic and topographic features. 



In considering the preglacial formations a brief outline of the general 

 topography of the region they occupy will first be given. Attention is 

 particularly directed to that part of the state of Missouri north of the 

 Missouri river, for the Pleistocene formations are but sparsely distri- 

 buted south of that stream. The region is a plain sloping to the south 

 and east, into which the larger streams have cut from 250 to 300 feet. Its 

 height at the northwestern corner of the state is over 1,200 feet above sea- 

 leval. It descends toward the Missouri to an altitude less than 1,000 feet 

 near Kansas city and to about 700 near the Mississippi at Palmyra. 



The Ozark uplift occupies a little more than the southeastern quarter of 

 the state. Its northern boundary leaves the Mississippi near the mouth 

 of the Meramec, passes northwest to the Missouri, thence westward a little 

 north of that stream to the mouth of the Maniteau and onward to the 

 vicinity of Sedalia. It there extends in an anticline running north to 

 the Missouri in eastern Saline county. The western boundary of the 

 uplift follows the trend of this anticline to the southwest and afterward 

 to the south. The Ozark uplift, as thus outlined, is composed mainly of 

 Silurian rocks. Along the northern margin of the uplift is an edging of 

 Devonian rocks, dipping gentl}^ to the north. Separated from the Ozark 



