184 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. 



The Lower Devonian yields 9 genera and 21 species — Athyris 1 7 

 Atrypa 3, Chonetes 3, Leptcena 1, Orthis 3, Bhynchonella 3, Spirifera 

 3, Spiriferina 1, Streptorhynchus 3. The Middle division contains 

 23 genera out of the 26, and 80 of the 116 species. The Upper 

 contains 14 genera and 37 species ; of these 10 genera and 16 

 species pass to the Carboniferous. It is essential to the history of 

 the Devonian fauna that I name the genera — Athyris 2 species, Cho- 

 netes 1, Piscina 1, Lingula 1, Procluctus 1, Bhynchonella 3, Spirifera 3, 

 IStreptorhyncJms 1, Strophomena 1, Terebratula 2. The large genera 

 are Bhynchonella 16 species, Spirifera 20, Streptorhynchus 6, Orthis 

 6, Cyrtina 4, Procluctus 4, and Terebratula 4. Regarding the 

 great discrepancy or smallness of this peculiar fauna as compared 

 with that of the continent and America, we must have regard to the 

 smallness of the area now exposed in England as compared with the 

 original area occupied by the Devonian sea, the accumulations of 

 which are now covered by the Secondary and Tertiary rocks of the 

 west and east of England, the Devonian floor or old surface being 

 hidden east of the Quantocks, North Devon, and Torquay. We have 

 proof of a rich Upper Devonian fauna in the rocks under London 

 and Turnford, at the depth of 1000 feet, and below the Cretaceous 

 series ; between these two places and JNorth Devon we can at pre- 

 sent only surmise the plane they occupy. 



The volume of the Paheontographical Society's publications by 

 T. Davidson, Esq., E.P.S., &c, devoted to the British Devonian 

 Brachiopoda, is worthy of the fame of its distinguished author ; in it 

 are described 116 species, the arguments for and against their 

 genuineness being impartially and consummately reasoned out, 

 figures of all the species and doubtful forms are given ; and when 

 we know the patience and skill required to adjust and discriminate so 

 dismembered and small a group as the British Devonian Brachiopoda- 

 out of such a mass of material occurring in the European and Ame- 

 rican fauna (1100 species), we may well be thankful that there are 

 men who have the required leisure and knowledge and who devote 

 their lives to one subject. Associated with Davidson in the Devo- 

 nian fauna, the names of Yon Buch, Schlotheim, Schnur, Dalman, 

 Sandberger, Hall, Billings, Dall, Conrad, Homer, Yanuxem, Bar- 

 rande, De Yerneuil, Koualt, Phillips, Sowerby, Xing, and M'Coy 

 must be prominently noticed. 



Lamellibranchtata. — The mass of the species of the class Conchi- 

 fera occurring in the Upper Devonian, and especially abundant, 

 are Asiphonida, through Aviculopecten, Pterincea, and the Mytilidse. 

 20 genera and 39 species are known, and 29 species illustrating 11 

 genera are in the Upper division ; yet of the whole bivalve fauna 

 only 4 genera and 5 species pass to the Carboniferous series in 

 North Devon, viz. Aviculopecten granosus, Sow., A. plicatus, Sow., 

 Pterincea damnoniensis, Sow., CucidlcmGriffithii, Salt., and Gurtonotus 

 unio, Salt. The Lower Devonian is even poorer, only 3 genera and 

 4 species occurring ; these are Aviculopecten polytrichia, Philip 

 Pterincea anisota, Phill., P. spinosa, Phill., and Ctenodonta Kratcha t , 

 Pom. ; the last mentioned is the only bivalve species actually con- 



