268 ARTHUR C. VEATCH 



widespread loess sheets of the southern Indiana and Illinois are 

 considered by Leverett to belong to the Iowan age. This 

 would seem to indicate that the lower loess is Illinoian and the 

 upper Iowan. 



By reference to Fig. I it will be seen that the sections given 

 above approach very close to the extreme southwest corner of 

 the triangular hill land. Gravel was observed to rise 18 feet 

 above the plain in a hill west of section 5. One-half mile west 

 of this point the hills turn northwest in Pigeon Plain. The 

 height of the gravels in the bluffs northeast of Enterprise 

 would indicate that they could be easily found if they existed 

 in this line of hills trending northeast. 



A very careful search, in all available places, failed to dis- 

 cover these gravels anywhere along the old river cut-off, and 

 it seems certain that they do not exist there. If this is the case 

 no considerable breach existed in the line of hills from the 

 southwest corner of the triangular upland to Warrick county, at 

 the time of the deposition of the gravel, e)se it would have been 

 filled with gravel, and at least some fragment of the deposit 

 would be left. This would seem to show the age of the cut- 

 off ; it was cut after the deposition of the gravel. 



These gravels and sands have been referred to the later Ter- 

 tiary for several reasons : 



First : The composition of the gravel is such that it cannot be 

 referred to the glacial period ; no pebbles of undoubted north- 

 ern origin being found in the beds. It is obvious that, on 

 account of its nearness to the southern limit of the glaciers, no 

 beds of gravels could have been deposited at this place either 

 during or following the ice-invasion without containing glacial 

 pebbles. The main component of the gravel beds is yellow 

 chert, probably derived from the Lower Carboniferous forma- 

 tions, through which the Ohio passes. The fragments of geodes 

 are doubtless mostly from the St. Louis limestone and Upper 

 Knobstone groups of Indiana. The quartz pebbles must have 

 come either from parts of geodes or the Carboniferous conglom- 

 erates or both. As the first ice invasion, in this part of the 



