CONTENTS. 



Page 

 Art. I. Historical Elog-e on M. Frederic Cuvier. By M. 

 Flourens, Perpetual Secretary of the Aca- 

 demy of Sciences, . . . n 



II. Further Reasons against the Chemical Theory of 

 Volcanos. ^By Professor Gustav Bischof of 

 Bonn. Communicated by the Author, . 14 



III. Summary of the most important Geognostical 

 Phenomena, with which it is necessary to be 

 acquainted in Preliminary Mining- Operations. 

 By the late Frederick Mohs, Councillor of 

 Mines at Vienna, and Knight of the Royal 

 Saxon Order of Civil Merit, &c. (Concluded 

 from vol. xxix. p. 21.), . . 26 



Repositories of simultaneous and of posterior Forma- 

 tion. — Disseminated Ores and Stockwerks, &c. — Kid- 

 neys, Nests, Putzen, and Lying Stocks. Layers of 

 foreign matter between the Kidneys, &c, and the in- 

 closing rock.— Pilons de Contact. — Venigenous Stock- 

 werks.— Beds, and the material of which they are 

 composed. — Bed-deposits and Bed-districts. — Veins. — 

 Changes in Vein-Stones and in neighbouring Rocks.— 

 Surface relations of the district to be examined. — 

 Characters of such pieces of country as form the 

 boundaries of different Mountain-tracts. — Estimate of 

 the value of Petrifactions, or Fossil Organic Re- 

 mains, in the determination of Rock-Formations.— On 

 the Bendings and Contortions of Strata. — Trap 

 Dykes.— Caution in regard to Shifts.— Case in which 

 Fossil Organic Remains may be used for assisting in 

 the determination of Formations. — Useful Minerals in 

 Secondary Rocks. 



