BULL. GEOL. SOC. AM. 



VOL. 23, 1911, PL. 15 



FlGUUE 1. A STILL WELL PUESEUVED PoUTIOX OF THE PLATEAU SLUFACE, 3,500 B^'EET 



ABOVE SEALEVEL 



FiuuKK 2.— -The ge.nekal Ai'I'Eaka.nce of the I'I'lam) 



Sliowinji the steeply sloping: character of the valley walls, and the decided shoulders 

 everywhere in evidence at the contact between these and the old plateau surface 



THE ORDOVICIAN-SILURIAN LIMESTONE: DOLOMITE BELT 



