iv TABLE OF CONTENTS. 



Page 



Lycett, J., Esq., and J. Morris, Esq. On Pachyrisma, a fossil 

 genus of Lamellibranchiate Conchifera 399 



Lyell, Sir Charles, President. Anniversary Addi-ess in February 

 1850 ^, xxvii 



. On Craters of Denudation, with Observations on the Structure 



and Growth of Volcanic Cones 207 



Mantell, Gideon A., Esq. On the Remains of the Dinornis and 

 other Birds, and the Fossils and Rock- Specimens recently collected 

 by Mr. W. Mantell in the Middle Island of New Zealand 319 



Mantell, R. N., Esq. On the Strata and Organic Remains exposed 

 in the Cuttings of the Branch Railway from the Great Western Line 

 near Chippenham, through Trowbridge, to Westbury in Wiltshire. . 310 



Moore, J. C, Esq. On some Tertiary Beds in the Island of San 

 Domingo 39 



. Notice of the Occurrence of Marine Shells in the Till 388 



Morris, J., Esq., and J. Lycett, Esq. On the Occurrence of 

 Mammahan Remains at Brentford 201 



. On Pachyrisma, a fossil genus of Lamellibranchiate Conchifera 399 



MuRCHisoN, Sir R. I. On the Distribution of the Superficial Detri- 

 tus of the Alps, as compared with that of Northern Em-ope Qb 



■ On the Earlier Volcanic Rocks of the Papal States and the 

 adjacent parts of Italy 281 



. On the Vents of Hot Vapour in Tuscany, and their Relations 



to Ancient Lines of Fracture and Eruption 367 



NicoL, Prof. J. On the Silurian Strata of the South-East of Scotland 53 



. Notice of the Occurrence of Coal near Erzeroom 367 



Prestwich, Joseph, Jun., Esq. On the Structure of the Strata be- 

 tween the London Clay and the Chalk in the London and Hamp- 

 shire Tertiary Systems 252 



RuxTON, Lieut. G. F. On the Volcanic Rocks of Northern Mexico 251 



Sharpe, D., Esq. Remarks on the genus NerincBa, with an Account 

 of the species found in Portugal 101 



■ . On the Secondary District of Portugal which lies on the North 



of the Tagus 135 



SiSMONDA, Prof. E. On the Discovery of a nearly perfect Skeleton 

 of the Mastodon angustidens near Asti in Piedmont 252 



Smith, J., Esq., of Jordan Hill. Note on the Shells found in the 

 Till by Mr. Cleghorn 386 



. On the Occurrence of Marine Shells in the Stratified Beds 



below the Till 386 



Stevenson, W., Esq. On a Gap in the Greywacke Formation of 

 the Eastern Lammermuirs filled by Old Red Sandstone Conglomerate 418 



Stowe, W., Esq. On a Cutting in the Railway near Buckingham, . 134 



Strickland, H. E., Esq. Notes on a Section of Leckhampton Hill 249 



Tylor, a., Esq. On the Occurrence of Productive Iron-Ore in the 

 Eocene Formation of Hampshire 133 



Weston, C. H., Esq. On the Diluvia and Valleys in the A-'icinity of 

 Bath \.. 449 



