R. XLIV W. 



H. XLIII W 



R. XLII W. 



R. xi.iy W. 



Fig. 1. Geological map of a portion of the Porcupine Mountains. Mich. 



2. Qunrtz-porplijry. 3. Diabase, Diabase-amygdaloid ("Trap"). 4. Sandstone and Conglomerate. .5. Diabase and 

 Diabase-nmygdaiOid ("Trap") 6. Sandstone witlitliin bands of conglomerate. 7. Dark-grey Sandstone and Black Siiale.— 

 (After Irving). 



