38 Kansas Academy of Science. 



lying beds; hence it forms the capping of prominent terraces 

 along such streams as the Kansas river and Mill creek and 

 others which flow eastward. 



The highest chert beds lie from 125 to 150 feet above the 

 level of the present streams. Along the Kansas river the chert 

 gravels show several feet in thickness in the bottom of the old 

 channel west and north of Manhattan. East of the Big Blue 

 the chert lies in detached patches, one a few miles east of the 

 Big Blue, then north and northeast of St. George, again one 

 mile west of Wamego, and northwest and north of that place. 

 It is extensively developed a few miles north of Rossville, and 

 is probably nearly continuous as far as Kiro. The next clear 

 trace of it is north of Fall Leaf, northeast of Lawrence, where 

 it extends widely for three or four miles to the vicinity of Lin- 

 wood. It is probable that traces of it may be found north of 

 Perry and Williamstown. 



An old bank of a channel marked by limestone cobbles is 

 found near Wilder at a corresponding altitude. 



Near Atchison, both south and north of the town, is a similar 

 deposit of chert gravel only about 80 feet above the Missouri, 

 and apparently in a channel trending northeast. The lower 

 altitude of the deposit at Atchison agrees with the conclusion, 

 based on other evidence, that it was in a different river system, 

 which had a lower drainage level. 



These chert gravels have never been found more than 10 feet 

 in thickness. No northern erratics have been found within 

 them, but they frequently rest upon it. It does not lie in a 

 plain exactly, but varies somewhat in altitude, as we should 

 expect if it marked not only the level of the shore or bars, but 

 also the bottom of the ancient river. 



Loiver Chert Gravels. Another chert gravel deposit has 

 been discovered and developed at several points, namely, a mile 

 west of St. Marys, east of Rossville, north of Kingville, north 

 of Grantville, northwest and north of Topeka. The bottom 

 of the deposit is 25 or 30 feet above the adjacent bottom lands 

 of the Kansas river. Northern erratics abound in the upper 

 half of it, and according to the testimony of a few, they occur 

 to the very bottom, but certainly has not been reached on that 

 point. The gravel and sand strata show thickness of 12 or 15 

 feet. 



