114 KANSAS ACADEMY OF SCIENCE. 



The Iowa prairies, that portion of the division of the Prairie plains 

 which lies in the northeast corner of Kansas, owes its peculiar surface 

 features to the fact that the rock formations are covered with a mantle 

 of drift, deposited during the glacial period. The southern border of 

 the glaciated area is a line approximately along the Kansas river in 

 Kansas, and from the mouth of that stream along the Missouri river 

 in Missouri. Since the deposition of the drift the streams have cut 

 their channels deep enough to expose the underlying rock formations 

 and revive in modified form the original topographic features. As a 

 result, there are in places fragments of terraces and escarpments simi- 

 lar to those which prevail in the Prairie plains south of the glaciated 

 portions. No attempt is made to define the limits of the Iowa prairies 

 beyond the boundary of the state. They extend into Missouri, and find 

 their larger development to the northeast in Iowa. 



Northeastern Kansas is the southwestern corner of Iceland — that is, it is the 

 southwestern part of the area which, in the times immediately succeeding the 

 Tertiary age, was covered with ice. . . . Where the ice halted and its ter- 

 minus remained stationary for a time, the melting being exactly met by the sup- 

 ply from the north, there was formed a terminal moraine as a result of the 

 accumulation of the solid matters it had carried along with it. . . . The true 

 hard-pan or till is a stiff, pasty, dark-brown clay, with pebbles and small boulders. 

 It seems to have been formed under the ice by the grinding of the material over 

 which the glacier passed — clay shales, soft limestones, and sands. . . . The 

 loess is often called bluff, because the bluffs of the Missouri river are formed of 

 it or capped with it. . . . Over immense areas it is substantially the same 

 material as that which gives color and muddiness to the water of the present 

 river. In some regions it takes color from local surroundings, and has streaks of 

 coarse sand or gravel, and becomes of orange brightness. (Hay, 8th Bien. Rep. 

 Kan. St. Bd. of Agri., vol. XIII, part II, pp. 118, 119.) 



Boulders lie scattered in small numbers in detached areas, north of the Kansas 

 river, from the Missouri nearly to the Republican, but west of the latter none are 

 noticed. The drift gravel extends a little farther. The origin of our drift, like all 

 others in the northern hemisphere, must be sought in regions far to the north. No 

 original ledges of quartzite or other metamorphic or igneous rock are found 

 within 300 miles of the northern state line, and it is only in the western portions 

 of Minnesota that these deposits are represented. No other material of our drift 

 is found so near. . . . The larger stones attain the size of true boulders, be- 

 ing sometimes ten feet in length, and weighing ten or twelve tons. The most 

 common are a metamorphic, stratified quartzite rock. The metamorphic action 

 has been very thorough, giving the boulders a hardness equal to common quartz, 

 and on that account they are frequently known under the nameof "hard heads." 

 . . , The large boulders are usually angular, and not so much water-worn as 

 the small pebbles. Next to quartz rock the most common material is greenstone. 

 A few of granite and syenite are also seen, but seldom as large as the quartzite or 

 greenstone. The deposit of drift material is not deep, being about five feet, 

 though in a few places It le twenty feet. The large boulders are quite numerous 

 on the Pottawatomie reserve, on both sides of the Kansas. They lie on the tops 

 of the bluffs and high prairies more frequently than on the lower lands. (Mudge, 

 1st Bien. Rep. Kan. St. Bd. of Agri., vol. VI, 2d ed., 1877-'78, pp. 51, 52.) 



