408 A. Marston — On the Transition Beds 



EXPLANATION OF PLATES XIX. AND XX. 



PLATE XIX. 



Fig. 1. Tere5rfl<M^fl!^rfl«c?es (Blum.), Pliocene, Monte Mario, Rome. 



2. Terelratula ampulla (Brocchi ), Sp., after Brocclii's original figure, Pia- 



centino. 



3. Terebratula BeffnoUi (Meneg.), Upper Miocene, Parlascio, and from a 



drawing by Sig. Meneghini. His collection. 



4. Terebratula Moncioni (Meneg.), from a drawing by Meneghini. His 



collection. Pliocene, Hills of Pisa. 



5. Terebratula Lyelliana (Sequenza), Pliocene, Sicily. 



6, 7. Terebratula Galeottina (Dav.), Middle Miocene, Gassino. 

 8. Terebratula rJiomboidea (Biondi), Eocene ? Cape Pachino, Sicily, after 

 Biondi. 

 9,10. Terebratella septata (PhUippi). 9. Exterior; 10. Interior of dorsal 



valve. Older Pliocene, Messina. 

 11, 12. Waldheimia cranium (Miiller) = T. euthyra (Philippi), 11. Exterior; 

 12. Interior of dorsal valve, enlarged from a figure by Dr. Suess. 

 Older Pliocene, Messina. 

 13, 13fl, Waldheimia ? Davidsoniana (Seq.). 13. Exterior ; 13a. Interior of 

 dorsal valve, enlarged after Sequenza. Upper Pliocene, Messina. 

 14. Waldheimia ? depressa (Seq.), Older Pliocene, Messina, after Sequenza. 

 15, 16. Waldheimia septigera (Loven) = W. peloritana (Seq.). 15. Exterior; 

 16. Interior of dorsal valve. Lower Pliocene, near Messina. 



17. Terebratella ? Spinellii (Meneg.), Eocene, Chiampo, collection of Sig. 



Meneghini. 



18. Terebratula Voglianei (Michelotti), Lower Miocene, Dego. 



19. Terebratulina caput-serpentis (Linne) Middle Miocene, Grangia, collection 



of Sig. Eovasenda. 



20, 20«. Terebratulina Tauriniensis (Seq.), Middle Miocene, Gassino, collection of 



Sig. Eovasenda. 20«!. Enlarged. 



21, 21a. Terebratulina striatula (Sow .•'), Eocene, Valle Organa, environs of 



Bassano. Mus. of Imp. School of Mines, Paris. 21a. Enlarged. 



22, 22a. Terebratulina Michelottina (Dav.), Eocene, Colle Berici. Mus. Imp. 



School of Mines, Paris. 22o, b, c. Enlarged. 



PLATE XX. 



'FiQ.ljijZ. Rhynchonella Upartita (Brocchi), after drawings by Sig. Meneghini. 

 Upper Miocene, Palazzo, near Siena. His collection. 2 and 3. Var. 

 plicato-dentata of Costa. 

 4, 4a. Bhynchonella Bolcensis (Massalongo), Eocene, Bolca. Mus. Imp. School 

 of Mines, Paris. 4a. Enlarged. 



5. Rhynchonella complanata (Brocchi), Middle Miocene, Gassino. 



6. Rhynchonella sicula (Seq.), M.S., Older Pliocene, near Messina. 



7. Rhynchonella Meneghiniana (Dav.), Eocene, Bolca, collection of Sig. 



Meneghini. 

 8, 13. Rhynchonella ^wcAn (Michelctti), different forms and ages. 13. Rhyn- 

 chonella deformata (Seq.), Middle Miocene, Hill of Turin. 

 14, 19. Rhynchonella polymorpha (Massalongo), different varieties and ages. Eo- 

 cene, Monte Spilecco, near Bolca, Zovo di Castelvecchio, etc., from 

 different collections. 



Ill, — On the Transition Beds between the Devonian and 

 Silurian Books. 

 By Alfred Marston, Esq., Ludlow. 



THE transition or passage-beds between any two large forma- 

 tions are always difficult to make out, and those between the 

 Old Eed Sandstone and the Silurian are no exception to the rule. 

 Much light has recently been thrown upon the latter, yet much more 



