162 The Monoclinic Pyroxenes of Neio York State, 



attention among mineralogists. Beck (Ref. 2) gives their occur- 

 rence as 2^ miles north of Edenville. The crystals are yellowish 

 gray and have roughened faces. They are broadly flattened par- 

 allel to c (001) and show striations parallel to the base. In de- 

 scribing them Beck mistook the base for the orthopinacoid. The 

 usual form of the Leucaugite is a combination of a (100), h (010), 

 7?i(llO), c(OOl), u(lll), 8(111) and o (221) (PL XIV, Fig. 1). 

 Gr. Y. Rath mentions a twin crystal (Ref. 39) of more prismatic 

 habit, formed according to the common law, and which has the 

 orthodome p (101) in addition to the above mentioned faces. The 

 striations parallel to c (001) were at first considered by him to be 

 due to irregularities of growth, but he subsequently correctly 

 ascribed them to twinning. He also notes the surface alteration 

 of these crystals to amphibole. 



These tabular forms were also described by Des Cloiseaux 

 (Ref. 12) who figured one with a hemihedral development in the 

 direction of the vertical axis, there being at one end the forms 

 p(l01), s(Tll), 0(221), e(Oll) and At(121) and at the other end 

 p (TOl), u (111) and a (312). 



Prof. G. H. "Williams has described a crystal from the Root 

 collection which was of the usual habit with the forms, c(OOl), 

 M(lll), s(Tll), o("221), m(llO), ^(010), a (100), but below, 

 toward the front, there was only o(221) and j9(101), showing it 

 to be hemihedral in the direction of the vertical axis. The lower 

 back quarter is just like the front but reversed so that the lower 

 half is a twin (PI. XIY, Fig. 3). 



The ordinary tabular form is to be seen in nearly every large 

 collection. The Leucaugite also occurs in white granular masses 

 in calcite as repi'esented by several specimens in the collection of 

 Columbia University. 



Other specimens in the same collection and from Warwick 

 township are a red-brown granular pyroxene from Amity, and a 

 greenish-gray cleavage specimen with numerous small scales of 

 graphite scattered through it. 



Beck, (Ref, 2), notes a black pyroxene from Rocky Hill near 

 Warwick. Specimens probably from this locality are in the 

 Columbia University collection. They are smaU interlacing pris- 

 matic individua,ls about two-thirds of an inch long. A few of 

 them show terminal faces probably unit pyramids, but they are 

 too rounded for determination. 



