134 KANSAS UNIVERSITY QUARTERLY. 



near the eastern limit of the Ottawa limestone, which is geologically 

 about 200 feet below the Oread limestone at Lawrence, yet the eleva- 

 tion of Olathe is about the same as Mt. Oread, while the low grounds 

 in the city of Lawj-ence are nearly 200 feet below. In other words, 

 there is a quite gradual and even decline in the surface westward from 

 Olathe to the foot of the hill at Lawrence. 



The variation in the relative thickness of the limestones and shales 

 causes variations in the relative heights of the terraces. If a limestone 

 system is unusually thick, as the lola. its upper surface gradually 

 wears away producing a gentle inclination as from lola to the river 

 near Chanute, and illustrated at /", fig. i. Should such a condition 

 be found with a thin bed of shale below it the terrace features might 

 not be noticed, and such is sometimes the case. 



Again, should the under beds be quite siliceous, as the Robinett 

 sandstone, or the Fort Scott flags, their resistance to decay may be 

 so nearly the same as the limestone above that a gradual slope will 

 result instead of a terraceil condition. Such occurrences arc by no 

 means rare. In this way Kansas is given a great diversity of jjhysi- 

 ograjjhic features. Vet we must admit that the prevailing and char- 

 acteristic topography of eastern Kansas is the terraced topography, a 

 condition which seems dependent principally upon the more or less 

 regular recurrence of alternating heavy beds of soft shales with light 

 beds of harder limestones and sandstones. 



Farther to the east in the Mississippian areas limestone greatly 

 predominates. There is therefore a lack of the alternation of harder 

 and softer parts, or the softer betls are not relatively so heavy. The 

 surface is much less markedly terraced, but in its place we see the 

 more gentle undulations, or the rounded hills, rather than flat mounds. 

 Even the novice can readily determine the boundary between the 

 Coal Measures and the Mississippian areas by means of their topog- 

 raphy.* 



To the west of the Carbo-Pcrmian areas the terrace features dis- 

 appear, because here the whole material is soft. The Dakota sand- 

 stone and sand hills just west of Abilene cause the valley of the Kan- 

 sas river to contract and the bluffs to disappear. They are partially 

 regained farther west towards Salina, for here the harder and 

 softer parts again alternate to a considerable e.xtent. But the mag- 

 nificent bluffs and deep broad valleys characteristic of the Kansas 

 river and tributaries from Junction City to Kansas City are nowhere 

 again equalled. Farther south towards Lyons, Hutchinson and 



*It must not be iinder.stood that tb':> Mississippi;iii areas have none of the terrace 

 features, for they have. Hut with that function they are the exception, while in the Coal 

 Measures they are the rule, and hence give charactt-r V) the topography. 



