GREENE: DAKOTA-PERMIAN CONTACT. 7 



posit of loess-like terrace material and alluvium, but a few 

 miles east of Clifton it is found at the 1280-foot contour, and 

 probably crosses the river about a mile southeast of Clifton. 

 West of the Republican river the Dakota is found as a thin 

 sheet on the terrace, as shown by well borings. Here the con- 

 tact is at about the 1240-foot mark, but rises steadily to the 

 south until the divide south of Manchester is reached, where a 

 height of 1360 feet is reached. There is, however, a constant 

 westward dip, so that the contact never extends very far west 

 in the valleys of eastward flowing streams. In the region just 

 described the contact passes near Idana, Oak Hill, Longford 

 and Manchester. 



East of the Republican river, in Clay county, the Dakota 

 forms a large outlier about three miles northwest of Green. 

 Here the contact is nearly up to the 1400-foot contour. From 

 this outlier west to the Republican river the dip of the Per- 

 mian is clearly and distinctly shown. 



From Manchester to Abilene the Dakota lies on a narrow 

 divide, but at its southern extension expands into a large 

 area. In this area it is very thin, and disappears in a large 

 expansion of sand hills, which may have originated from 

 poorly lithified sandstone, or from stream or wind sediments. 



From Abilene east to within three miles of Chapman, sand 

 and sand hills occur on the north side of the Smoky Hill. 

 There is much doubt as to the origin of these deposits. In this 

 connection, the observations of Hay^ in the vicinity of Junction 

 City are interesting. He found sand hills near Junction City 

 at or about the same level as those in the vicinity of Abilene. 

 He says : "A more recent examination of the high-level sand 

 dunes previously referred to revealed the fact that they are 

 residual beds, resting on and abutting against undoubted out- 

 liers of the Dakota." Two areas of Dakota are shown on his 

 map. These are only one-half of a mile west of the eastern- 

 most outcrops in Washington county, although the trend of 

 the eastern outcrop of the Dakota is southwest throughout the 

 state. 



8. H»y. GeoL of Ft Riley, etc. BnlL 187. U. S. G. S., p. 28. 



a-Univ. ScL Bull., Vol. V. No. 1. 



