222 



acknowledgment of his election as Corresponding Member ; Henry 

 Davis, McGregor, Iowa, Mai'ch 23d, 1863, proposing exchange of 

 shells, &c. ; the Verein fiir Naturkunde, Wiesbaden, November 1st, 

 1862; St. Gallische Naturwissenschaftliche Gesellschaft, St. Gallen, 

 November 20th, 1862, acknowledging the receipt of the Society's pub- 

 lications ; Verein fiir Naturkunde, Wiesbaden, November 1st, 1862, 

 OfFenbacher Verein, November 10th, 1862, presenting their publica- 

 tions. 



Mr. Bouve announced the arrival of the boxes containing 

 the casts of the bones of the Megatherium in the British 

 Museum, presented by Joshua Bates, Esq., of London. 



Prof. Charles E. Hamlin, of Waterville, Me., was elected 

 Corresponding Member. 



Messrs. George L. Vose and John Wetherbee, Jr., of Bos- 

 ton, and Mr. L. Trouvelot, of Medford, were chosen Resident 

 Members. 



April 15, 1863, 



The President in the chair. 



Dr. C. T. Jackson presented to the Society a series of speci- 

 mens of the magnesian limestone of the Lower Silurian series 

 of Prairie du Chien, containing crinoids and fossil shells char- 

 acteristic of that formation, namely, Orthis striatula, Stro- 

 phomena expansa, Pleurorhyncas, Rhynconella, and a species 

 of Nucula or of Lingula. These fossils and rocks form the 

 upper portions of the bluifs in Prairie du Chien, near the 

 Mississippi and Kickapoo Rivers, and overlie the white 

 sandstone strata, which bear the galena veins of Dubuque 

 and Galena, and the deposits of copper ore near Prairie du 

 Chien, 



Dr. Jackson gave a description of the mode of occurrence of the 

 galena at Dubuque, and stated that it is found in crevices and 

 small caverns in the white sandstone, generally quite loose and free 

 from the rocks, and surrounded by ferruginous clay. No deep run- 

 ning veins of the ore have been discovered, .and there are no deposits 

 of sufficient extent to warrant the erection of permanent works for 

 mining operations ; and hence the business of lead mining in that 



