290 



Penfield and Foote — Clinohedrite. 



exhibits the normal or most highly developed type of mono- 

 clinic symmetry, and specimens which show the lower degree 

 of symmetry are so rarely met with that it seems probable that 

 they are only the result of an accidental development of a part 

 of the crystal faces. 



The crystals of clinohedrite on a specimen sent to us by Mr. 

 Hancock were exceptionally fine and well adapted for crystal- 

 lographic study. They were about 4 mm long, and from 2 to 3 mm 

 in diameter, and had the habit represented in figs. 1 and 2, the 



latter being drawn with the pinacoid h, 010, in front. They 

 were generally attached at the end represented as the lower 

 one in the figures, and the forms at that end, when they could 

 be observed, were rounded and graded into one another so that 



4. 



it was difficult to decide what ones were present and how they 

 should be represented in the figure. At the upper, or free 

 ends of the crystals, however, the faces were exceptionally per- 

 fect, and gave beautiful reflections. The crystals on the speci- 

 mens sent by Mr. Nason were not so well suited for crystallo- 

 graphic study, several of the forms being striated and rounded, 

 and it was so difficult to obtain satisfactory measurements that 



