104 



INDEX TO THE STRATIGRAPHY OF NORTH AMERICA. 



rendered generalization difficult. A systematic study of the whole area was made 

 in 1905 by Ulrich/^ who arranges the formations as follows: 



Classifimtion and synonymy of the formations of the " Magnesian" or "Ozark series^' in Missouri. 



a The names "Folley limestone," "Cap-au-Grfes sandstone," and "Winfield limestone," together with a number 

 of other new names, were published by Keyes in Some geological formations of the Cap-au-Grfes uplift: Proc. Iowa 

 Acad. Sci., vol. 5, 1898, pp. 58-63. 



6 The names "Finley limestone," "Maishfield sandstone," and "Decaturville limestone," appear in a provi- 

 sional table of geologic formations in Missouri, by Shepard, E. M., Bull. Bradley Geol. Field Sta., 1904, p. 42. 



ULrich remarks: 



As has already been stated, none of the classifications and subdivisions of the Ozark series 

 of rocks, briefly discussed in the foregoing pages, has proved wholly satisfactory. An arrange- 

 ment that would be above criticism is perhaps impossible. Some of the beds vary so greatly 



