Plate 21 



A. Camptonite dike from the bed of the Ausable 

 river, north edge of area. Augite (A). The ground- 

 mass is a fine aggregate of brown, hornblende prisms 

 and plagioclase, probably with analcite. White light, 

 actual field 0.08 inch or 2.0 mm. 



B. The same rock as A. but showing brown, basaltic 

 hornblende (Hb), olivine (01) and augite (A). White 

 light, actual field 0.08 inch or 2.0 mm. 



