EXPLANATION OF PLATES. 



PLATE 1 — 



Fig. 1. Horizontal strata. 



2. Inclined strata. 



3. Unconformable strata. 



4. Synclinal. 



5. Synclinal and anticlinals. 



6. Synclinal and anticlinals K. side Covell creek 



near stone bridge. 



7. Synclinal in St. Peters N. of Milling-ton. 



8. Section across 111. Valley, throug-h Buffalo 



Rock. 



9. Strata W. end Tunnel, line La Salle Tp. 



10. Section strata of La Salle Co. E. to W. 



11. Section strata of La Salle Co. perpendicular. 



PLATE II— 



Fig. 1, 2. Sandstone bluffs. 



3, 4. Rock shelters "caves," p. 18. 



5. La Salle Limestone a and c hard rock; b 



shale weathering* out when a falls over as 

 at Bailey Falls. 



6. Cracks in shale, surface. 

 13. Cracks in shale sections. 



7-8. See pag-e 59. 



9. Ming-ling- of strata p. 10. 



11. Marking-s on exterior of fossil tree trunks. 



12, 14. 15, 16, pa.ge 57, for 17 read 12. 

 18. See pa.ge 10; for Fig-. 9 read 19. 



Plate of shells is from W. W. Calkins' Land and 

 Freshwater Shells of La Salle county. 



