Fig. 9, — Generalized map of North America in Paleozoic time, showing In white 

 the lands or positive elements, in darkest shading the three geosynclines or sub- 

 positive elements, and in lightest shading the extensive neutral medial area of the 

 continent. The two heavy black lines indicate the Cincinnati and Ozark (Kan- 

 kakee) uplifts. From the Pirsson-Schuchert * *Text-book of Geology, ' ' published 

 by John Wiley & Sons, Inc. 



