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S. L. Penfield — Crystallized Vanadinite. 441 



There are, however, several specimens of a slender Murchisonia 

 which is probably M. gracilis, a single doubtful Maclurea and 

 specimens of Ophileta in abundance. I have found one incom- 

 plete Orthoceras, but in too poor condition to be identified. 

 Near the E. R crossing, I obtained also a well-preserved bryo- 

 zoan, a new species of the genus Ptilodycta. 



While the two species of brachiopods which have been posi- 

 tively identified, belong to both the Trenton and the Hudson 

 Kiver periods, the fact that the rocks of the latter do not include 

 limestones in eastern New York, is strong evidence that these 

 fossils are of Trenton age. The character of the associated 

 genera and the appearance of the rock also strengthen this view. 



If the limestones of the eastern and western belts are iden- 

 tical, as seems to be proved both by their connection at Ghent 

 and by their similar lithological character, there can be no 

 reasonable doubt that the limestone containing Trenton fossils 

 immediately underlies the graptolitic shales of the Hudson River 

 group. 



The facts, as far as collected, are suggestive of a synclinal 

 having the Trenton limestone outcropping on both sides, and 

 with the eastern edge pushed over westward. 



During the coming year I hope by mapping out the district 

 carefully, and noting the strikes and dips, to get more exact in- 

 formation than I am able to present to-day. 



Before closing I wish to express my indebtedness to Professor 

 James Hall, the State Geologist and his assistants, who have 

 identified for me the fossils found, and without whose aid this 

 paper would not have been written. 



LII. — Crystallized Vanadinite from Arizona and New Mexico ; 

 by S. L. Penfield. 



The occurrence of vanadinite in various localities in Arizona 

 has been noticed by B. Silliman* and W. P. Blake,f and of 

 crystals from the Black Prince Mine, Pinal Co., Arizona, by F. 

 H. Blake.:): The latter mentions, as the most common forms, 

 prism and pyramids of the first order, prism of the second order 

 and the basal plane. Through the kindness of Mr. L. Stadt- 

 muller I have been able to examine a number of specimens 

 from the above and other localities in Arizona and New 

 Mexico which were in the collection of the late Professor B. 

 Silliman. I have also examined a number of specimens in the 

 collection of Professor Geo. J. Brush. The crystals from Pinal 



* This Journal, III, xxii, ]98. f This Journal, III, xxii, 410. 



X This Journal, III, xxviii, 145. 



