ADAMS COUNTY. 47 



Clay, with large boulders 40 00 



Black soil 2 6 



Clay, stratified 6 



Very tough blue clay 20 



We have in this section eighty -five feet of what may be considered true Drift, 

 consisting of unstratified clays containing gravel and boulders. The upper six 

 feet of the section probably represents the age of the Loess more properly than 

 any other division of the Quaternary system, and its formation is explained by 

 Prof. Lesquereux, in his chapter on the formation of the prairies, published in 

 vol. I of this report, page 246 et seq. 



The ancient Post Tertiary soil, which was reached at a depth of ninety-one 

 feet from the surface, and the stratified clays which underlie it, are of an older 

 date than the Drift proper, and were no doubt formed under very different con- 

 ditions. So far as we are aware, this was the first point in the State where a 

 bed resembling the surface soil was observed below the Drift, as this shaft was 

 sunk in 1859, but no public notice was made of it at that time, as it was then 

 supposed to be a merely local phenomenon that might not be verified elsewhere. 

 Fragments of wood, and also of bones, were reported to have been found in it 

 here, but we were not able to obtain specimens of them, and cannot vouch for the 

 truth of the report. Susequent discoveries at other points, however, 

 show that wood, in an excellent state of preservation, is often found in this 

 ancient soil, as well as in the underlying stratified clays, and in the shaft 

 at Bloomington, at the depth of one hundred and eighteen feet, a considerable 

 quantity of wood, some of which was perfectly sound, was taken from a similar 

 deposit These stratified clays, and the sands frequently associated with them, 

 appear to have been entirely of fresh water origin, the fossil shells which they 

 have afforded being all of lacustrine or fluviatile species. 



At Camp Point, a few miles east of Coatsburg, the Quaternary beds were all 

 penetrated in sinking a tank well at the railroad station. They were here only 

 sixty feet in thickness, but no note was made of the character of the different 

 beds passed through. Probably the lower beds of stratified clays, and the an- 

 cient soil above them, were not found here, and the beds passed through were 

 only the surface soil and subsoil, and the true Drift deposits. From the soft 

 and yielding character of the beds, a satisfactory natural section of them is 

 rarely met with, and it is only where they have been penetrated in sinking coal 

 shafts, wells, and other artificial excavations, that a correct section of the whole 

 series can be seen. Along the breaks of the streams, the Drift clays and subor- 

 dinate beds of superficial material are generally eroded into sloping hill sides, 

 covered with soil and vegetation, down to the fundamental rock on which they 

 rest, and only very meagre exposures of the beds are to be found on the water 

 courses. 



