448 GEOLOGICAL EXCLUSION TO THE ROCKY MOUNTAINS. 



die of the State. The salt measures are barren gray beds above the 

 highest Light-colored Permian, and contain beds of rock salt from 100 

 to 200 feet in thickness. 



The route from Clay Center to Kansas City, and also that running 

 northeastward across Nebraska to Omaha, lies mainly upon limestones 

 and shales of Permian and Carboniferous age. 



Between Clyde and Clay Center the road follows a valley which had 

 been enormously widened in Quaternary times and cut below the level 

 of the plains, as preserved ID the dividing ridges between the streams. 

 Leaving this valley at Clay Center the road ascends the divide between 

 the Republican and Blue rivers, and enters upon the Paleozoic area. 

 The underlying rock is now the horizontal yellow limestone of the Per- 

 mian, to whose existence the persistence of the divide is due. 



The road enters the valley of the Kansas or Kaw River at Manhattan. 

 Twenty miles up this river, in a southwesterly direction, on a point 

 overlooking the junction of the Republican and Smoky Hill rivers and 

 within the Fort Riley military reservation, there is a stone monument 

 marking the geographic center of the United States as determined in 

 1880. 



At Manhattan a good cross section of the Kansas Valley is obtained. 

 On the opposite side of the river are heavy beds of orange-colored 

 loess. Near this station, and again near McFarland, are outcrops of 

 the Hint beds, which are a conspicuous feature of the Permian through- 

 out several counties. The road now passes into the Coal Measures, 

 which constitute the prevailing formation of the uplands as far as 

 Kansas City. Drift boulders of red quartzite from Minnesota, sup- 

 posed to come from the drift in northern Kansas, are seen close to the 

 road before entering McFarland. 



Between Topeka and Kansas City d rift is abundant, and its presence 

 is shown by the form of the low hills to the north of the road. 



At Lawrence a considerable morainal deposit is seen on both sides 

 of the river, across which it once probably formed a dam. 



