ii4 



Cincinnati Society of Natural History. 



and it probably owes its highly crystalline character to con- 

 tact metamorphism, produced by them at the time of their 

 eruption. 



7. The staurolite in this mica-schist has altered completely 

 to muscovite while the garnets are in process of alteration to 

 chlorite. 



8. The study of granite soils with the aid of the miner's 

 pan showed the presence of a number of minerals not noticed 

 in the thin sections. This method also showed a wide dis- 

 tribution of zircon, with good terminations and numerous 

 inclusions. It also brought to light many garnets with a 

 cubical outline. 



