PAYETTE COUNTY. 137 



was noticed, fonr inches in diameter and sixty feet high. The Kaskas- 

 kia river (or Okaw, as it is commonly called,) has a deep channel and 

 often sandy banks. Its bottoms below Vandalia are generally two 

 miles wide, diminishing to one mile at the north county line. On the 

 bottoms there is a heavy growth of timber, including pin oak, walnut, 

 red oak, bur oak and cotton wood ; and in wet places opposite Van- 

 dalia I noticed Gatalpa bignonioides. The hills south of Vandalia are 

 from fifty to seventy-five feet high. Towards the northern part of the 

 county they are generally higher, being about 80 feet near the north 

 county line, and 150 feet near the mouth of Beck's creek. On the other 

 streams the hills are lower. On Buck creek are found cornns floricla, 

 white walnut, hornbeam, sugar tree, black gum, red oak, ash, linden, 

 cotton wood, sycamore and white oak. 



Stratigram hie a I Geology. 



In this county the formations consist of the Quaternary aud the Coal 

 Measures. 



Alluvium. — The wide fiat bottoms of the Kaskaskia embrace an exten- 

 sive area of alluvium. 



Prairie Formation. — The prairie near Dismal creek has a grayish soil 

 containing a few small concretions of oxide of iron. Nine miles east of 

 Vandalia on the national road the prairie soil contains a good deal of 

 iron ore. 



On Flat prairie, ten miles south-west from Vandalia, the roadside 

 washings expose: 



Ft. 



1. Dart soil 1 



2. Dark brown clay w.th darker stains exposed 2 



This I consider older than the alluvium, and may be equivalent to the 

 Bottom prairie of the Mo. Geol. Beport. 



On the north side of Big creek there is exposed six feet of dark and 

 buff clays, containing small nodules, probably loess. 



Drift. — This formation is well developed in this county. A well near 

 Bamsey was dug 100 feet deep through clay and gravel to solid rock. 

 The mound west of Vandalia is about 100 feet above the general surface 

 of the surrounding country, and 55 feet of drift is exposed on the bank 

 of the river at the National road bridge. This would make the total 

 thickness of the drift in this county not less than 150 feet ; probably a 

 little more, but not over 200 feet. 



On the bank of the Kaskaskia river, at the National Boad bridge, 

 the npper ] 5 to 20 feet consists of red clay with coarse sand and gravel 



