CONTENTS. Xi 



ARTICLE XXIV. 



Chemical Examination of two Minerals from the neighbourhood of [leading, Pennsylvania; and on the 



occurrence of Gold in Pennsylvania. By Charles M. With, rill. Ph. 1»., 



ARTICLE XXV. 

 On a New Variety of Asphalt: (Mblah-asphait.) By Charles M. Wetherill, Ph. I" . 



ARTICLE XXVI. 

 On the Decomposition of the Alkaline Sulphates by Hydrochloric &.cid and Chi Tin.' Bj R A Tilghman, 



ARTICLE XXVII. 

 Notes on the Classification of the Carabidae of the Unit 3l By John L. Lc Conte, M. !>., 



ARTICLE XXVIII. 

 Revision of the Elateridse of the United States. By John L. Le Conte, M. D., ..... 



Appendix, ................. 



Index of Genera, . 508 



