1922] 



NATURAL SCIENCES OF PHILADELPHIA 



115 



crystals, or to poor reflections. The results of the measurements 

 of the others are given in Table II. 



The following forms were noted, (fig. 1) : a (100), b (010), m (110) 

 w (650), 1 (430), B (10.7.0), z (850), and p (101), of which w, B, 

 and z are new. Their characters in brief are: a (100) exists as a 

 very narrow face; b (010) is a large brilliant face which usually 

 gives multiple reflections; m (110) is a wide pearly face, free of 

 striations, and usually giving fair, bright reflections; w (650), 1 

 (430), B (10.7.0), and z (850) are line faces forming a striated zone 

 between m (110) and a (100); p (101) is a wide, deeply striated 

 dome, giving a series of multiple reflections, of which the p angle 

 is fairly constant. 



The average coordinate angles of m (110) and p (101) were used 

 to determine the axial elements given at the top of Table II. 



The cleavage of wavellite was given by Senff as parallel to p 

 (101) and b (010) rather perfect; and by Des Cloizeaux as parallel 

 to m (110) and b (101). The only cleavage noted by the writer 

 was a very perfect one parallel to m (110). 



Table II. Wavellite Forms, Llallagua, Bolivia 



a :b : c = .5520 : 1 : .4067 

 po = .7365; qo = .4067 



New forms marked * 



Wavellite, Trimble's Mine, Pennsylvania 



Trimble's mine is the famous locality for wavellite listed in the 

 older books as "White Horse Station, Chester County." The old 

 abandoned limonite pit so described is situated about a mi l e 

 northwest of Planebrook Station on the Philadelphia and Chester 

 Valley branch of the Philadelphia and Reading Railroad, in Chester 



