108 



BULLETIN No. 145 



[April, 



Hall and Miller (66) reported the carbon and nitrogen con- 

 tent, and ratio of carbon to nitrogen in samples of various ma- 

 terials taken from such great depths as to preclude all possibility 

 of weathering. Since the nitrogen was always found to be associ- 

 ated with carbon it was regarded as being of organic origin and 

 as being' derived in part from the organic matter present in the 

 clay at the time of its deposit. These results are shown in Table n. 



TABI<B 11. CARBON AND NITROGEN IN UNWEATHKRED ROCKS 



NOTES 



1. A grey coarse sand. 



2. Pale grey fine sandy rock. 



3. Coarse yellowish sand. 



4. Fine yellowish sand. 



5. Solid grey clay. 



6. Solid dark green clay. 



7. Close grey and red mottled clay. 



8. Hard grey shale. 



9. 10, 12. Hard grey clays from the coal pit shafts at Dover. 

 11. Hard grey clay. 



13. Hard grey clay. 



14. Reddish sandy brick earth. 



It will be seen from a study of the above tables that under 

 normal conditions the nitrogen-carbon ratio of the soil has a tend- 

 ency to become narrower as the age of the organic material in- 

 creases. The ratio, however, never becomes narrower or ever 

 equal to the ratio of the more common proteins contained in the 

 humus producing materials. 



(b) CARBON, NITROGEN AND PHOSPHROUS IN ILLINOIS SOILS 



Before discussing the phosphorus-carbon and phosphorus- 

 nitrogen ratios in the soil it seemed desirable to determine as closely 

 as possible these ratios in fresh material out of which humus might 

 be formed. 



