532 PROCEEDINGS OF THE AMERICAN ACADEMY. 



infrequently doubly terminated. In the large group to which reference 

 was made about twenty of the tabular crj^stals are found on a surface 

 measuring about 15 by 20 cm., several of the crystals over 3 cm. on an 

 edge, and attached by an edge in such fashion as to present an appear- 

 ance altogether foreign to epidote. The crystals are frequently twinned 

 according to the ordinary law for epidote, twinning plane the orthopin- 

 acoid. 



Measurement of numerous crystals proved the presence of some 

 twenty-six forms as shown in the following list. The smaller crystals 

 were measured on the two-circle goniometer and most of the faces gave 

 excellent reflections. For the large crystals contact measurements were 

 used, and these, with a study of zonal relations made determinations of 

 forms fairly certain. A few forms were thus found that were not 

 observed on the smaller crystals. Two forms new for epidote are 

 marked with an asterisk. 



c (001), b (010), a (100), u(210), z (110), o (Oil), e (101), 



i (T02), N (304), r (TOl), 1 (201), n (Til), a (212), F (154), 



Z (232), ^ (353), <t> (T'^O' ^ (T41), E (T51), q (221), O (544),* 



j (755),* X (322), y(2ll), R (ill), * (il3). 



Of these forms c, a, b, u, r, and n are nearly always present and 

 define the habit of most crystals, z, e, o, and q are also found on many 

 crystals ; the remaining forms are rare and subordinate in development. 

 The forms may be characterized as follows : 



c (001) always present, bright and unstriated, often broad. 



b (010) always present, always dull and striated parallel to intersec- 

 tion with n ; generally has narrow faces. 



a (100) always present ; the largest face on tabular crystals; bright 

 butt often striated faintly horizontally. 



u (210) always present, generally with large bright faces. 



z (110) generally quite subordinate to u but frequently present as a 

 narrow face and always pitted and dull. 



o (Oil) bright face, generally small. 



e (101), i (T02), N (304), 1 (201) are infrequent forms in orthodome 

 zone, generally narrow, bright and unstriated when they do occur. This 

 zone is remarkably jDOor in forms and free from striation as compared 

 with most crystals of epidote. 



r (TOl) always present, broad, generally striated lightly and less 

 brilliant than c with which it is easily confused on the crystals. 



