jS. L. Penfield — Pyrite crystals from French Creek. 209 



Chara does not seem to be well taken since we have abundant 

 examples of the shells of small mollusks very evenly distrib- 

 uted through the matrix. The objection that Chara could not 

 grow in the depth of salt water indicated by the numerous 

 corals and Brachiopods, is much more serious and may be fatal 

 to the view that it can be Chara. Be that as it may, the evi- 

 dence both p?*o and con is presented, and it is to be hoped that 

 some one may be able to relegate it ultimately to its proper 

 systematic position. 



In order that these organisms from the Falls of the Ohio 

 may be referred to independently I propose to call them Calci- 

 sphwra Lemoni after the collector, particularly as I can not 

 regard them as Foraminiferal and identical with Dawson's 

 Saccammina, and moreover the name Calcisphmra is not mis- 

 leading whatever their nature may eventually be proved to be. 



Art. XXIV. — On some curiously developed pyrite crystals 

 from French Creek, Delaware Co., Pa.; by S. L. Pen- 

 field. 



Ordinarily simple octahedrons and cubes of pyrite occur 

 at French Creek, Pa., while occasionally rarer combinations are 

 met with, as the cube with 7r(420), i(4-2). The crystals are bright 

 and have a good luster, but are usually covered with vicinal 

 faces and are sometimes quite distorted by them. The crystals, 

 which are to be especially described in the present article, are 

 live which are in the collection of Mr. C. S. Bement of Phila- 

 delphia, and two in the collection of Professor Geo. J. Brush 

 of New Haven, and I take pleasure in expressing my thanks 

 to these gentlemen for their generosity in placing the crystals 

 at my disposal for study. They are in all cases isolated crys- 

 tals, built out in all directions and showing no attachment. I 

 have been unable to obtain any exact information as to their 

 mode of occurrence, and can only state that they are very rare 

 and are from the iron mines of French Creek. 



The special peculiarity of these crystals is that they are ab- 

 normally developed, i. e., lengthened out, in the direction of 

 one of the crystallographic axes. If we take this direction as 

 the vertical, the crystals will appear either as steep tetragonal 

 or orthorhombic pyramids. In all cases the pyramidal faces 

 are curved toward the apex and as a result of this the pole 

 edges, running from the lateral to the vertical axes, are curved 

 while the middle edges, running between the lateral axes, are 

 perfectly straight. Owing to this curving the angles between 

 the faces can not be measured with the reflecting goniometer 



