154 The MonocUnic Pyroxenes of New York State. 



in the collection of the National Museum at Washington. It is 

 3^ inches long, and perfectly formed. The interesting feature 

 about it is the hemihedral distribution of the planes. At the 

 upper end are the planes m(111) ver}" large, s( 111) and o(221), 

 at the lower end ^3(101), c(OOl), •uClll) small, s(lll) and 

 o( 221). In the prismatic zone are a (100), h (010), m (110). On 

 PI. XIV., Fig. 2 there is given a drawing of this crystal copied 

 from Prof. William's paper. 



Bussel, St. Lawrence Go. — Many of the forms from Russel are 

 stout greenish black often doubly terminated individuals, of vari- 

 able size. They have moderately smooth prismatic faces, but 

 much pitted terminal ones. The ordinary combination of planes 

 is a(100),&(010),?7i(110),p(T01) and u (111) (PI. XY., Fig. 7) ; 

 o ( 221), was seen on one specimen. This same form of crystal is 

 sometimes labeled Pierrepont. A parting parallel to a (100) and 

 c (001) is present. One form in the Columbia Universitj^ collec- 

 tion is ver}^ flat parallel to 6 (010) and shows onl^^ the planes 

 b (010) and m (110). (PL XIII., Fig. 3). It is much decomposed. 



Thousand Islands. — Many of the diabase dikes of these islands 

 contain aiigite, which in section is of a brownish j^ink color, 

 with faint pleochroism. The prismatic cleavage is pronounced 

 and twinning abundant. The augite alters to pale green chlorite 

 or to a yellowish brown aggregate resembling serpentine. (Ref. 50.) 



Ghilson Hill, Ticonderoga^ Essex Co. — The rock at this locality 

 is a gneiss containing much calcite. The minerals found in the 

 former are scapolite, quartz, graphite, apatite, titanite and pja'ox- 

 ene. These latter which have been described by F. L. Nason 

 (Ref. 39), are peculiar on account of the large size of the crj^stals, 

 and the inclusions which ihey carr3^ Two specimens in the col- 

 lection of the New York State Museum at Albanj?- are said to be 

 the largest ever found in the State and perhaps in the world. 

 The larger of the two measures 36 inches in circumference and is 

 18 inches long, and weighs over 100 pounds, while the second is 

 18 inches in circumference and 12 inches long. The faces present 

 are a (lOOj, h (010) and m (110), all equally developed. There are 

 no terminal faces, the flat ends of the crystals being due to part- 

 ing planes. The crystals are commonly lamellar and badly 

 decomposed, and the faces are roughened hj numerous small in- 

 terrupted striae. Calcite often penetrates the crystals and to- 

 gether with quartz often forms rounded included masses. Graph- 



