106 8. L. Penfield — Chemical Composition of Aurichalcite. 



exceedingly important one. for it throws some light on the 

 general stratigraphy of a portion of Florida of which little was 

 hitherto known. The well record is as follows : 



0- 400 feet. "Sands with thin layers of semi-vitrified sand 

 at 50 and 60 feet.'"' 



400- 800 feet. Very fine grained soft, greenish gray quartz 

 sand, containing occasional foraruinifera and 

 water-worn shell fragments. 



800- 850 feet. Xo sample. 



850- 860 feet. White sands with abundant foraminifera of 

 four or five species. 



860- 904 feet. Xo sample. 



904- 915 feet. Gray sands containing sharks' teeth, small 

 water-worn shell and bone fragments, sea 

 urchin spines and lithified sand fragments. 



915-1000 feet. Xo sample. 

 1000-1212 feet. Samples at frequent intervals. Vicksburg lime- 

 stone containing Orbitoides in abundance 

 throughout, together with occasional inde- 

 terminable fragments of molluscan casts,corals 

 and echinoderms. It is a creamy white, hard 

 homogeneous limestone throughout. 



There was also sent a box containing two species of Dentalium 

 and a Turritella, all of Miocene faeies, but, unfortunately, no 

 data could be furnished in regard to the depth at which they 

 were found. 



The ages of the series overlying the limestones could not be 

 determined definitely from the material received, but the 

 organic remains from 800-915 feet suggest Miocene, especially 

 if the unlabeled sample belongs here, which is probable. The 

 400-800 feet beds contain several of the same foraminifera 

 that are found at 850-860 feet, and probably are part of the 

 same formation. 



Art. XIY. — On the Chemical Composition of Aurichalcite ; 

 by S. L. Penfield. 



The material for the analysis in this paper was received by 

 Professor E. S. Dana some years ago from an unknown local- 

 ity in Utah. Very good specimens of aurichalcite occur at 

 both the Kesler Mine, Big Cottonwood and Cave Mine, Beaver 

 Co., Utah, and the specimen under investigation very closely 

 resembles one from the Kesler Mine in the cabinet of Professor 

 Geo. J. Brush. As some question still exists regarding the 



