ANNIVERSARY ADDRESS OF THE PRESIDENT. 



207 



Pavositidse, with 5 genera, and Cyathophyllida3, with 20 ; the 

 remaining 7 families have only 1 or 2 genera each and but few species. 

 No form of Coral is known above the Yoredale rocks, and only 

 2 genera and 2 species occur in the Yoredale series, viz. Favosites 

 tumidus, PhilL, and Zaphrentis Phillipsii, M.-Edw. The Calciferons 

 Sandstones yield 3 species, Alveolites septosus, Fleming, Favosites 

 tumidus, Phill., and Lithostrotion junceum, Plemiug. 



The Lower Limestone Shales (mostly those of the west of England) 

 have yielded 13 genera and 30 species ; the nature of the deposit 

 greatly influenced and determined the presence of the species. 

 Nearly all the Corals in the shales are simple forms and dwarfed 

 in habit, certainly more so than those species that lived in 

 clearer and deeper water, where lived most of the compound 

 forms which occur so abundantly in the limestone beds. This 

 difference, under petrological association, is manifest on carefully 

 examining the strati graphical position of the corals in many locali- 

 ties. The Carboniferous Limestone is coralliferous throughout, 

 and the fullest evidence may be obtained of large and extensive 

 reefs composed essentially or mainly of the Eugosa, Lithostrotion, 

 Lonsdaleia, species of Cyatliophyllum, and numerous other species. 

 The Carboniferous Limestone of the British Islands yields every 

 known genus and species catalogued ; in other words, 36 genera 

 and 141 species (all the Carboniferous Actinozoa known) are found 

 in the Carboniferous Limestone in one locality or other in Great 

 Britain and Ireland. The whole class culminates in the Mountain 

 Limestone, for only 2 genera and 2 species pass to the Yoredale beds 

 {Favosites tumidus and Zaphrentis Pliillipsii). This sudden ter- 

 mination in time of the Actinozoa was undoubtedly due to those 

 physical changes which took place in consequence of the elevation of 

 the sea-bed and prior to the deposition of the Permian. Our lists, 

 tables, and collections of the Carboniferous Corals have not been 

 studied sufficiently to enable us to construct proper distribution 

 tables ; but the accompanying table of 19 of the chief British genera 

 is intended to show their geographical distribution in Britain, also 

 in the chief locality in Europe, and further their correlation with 

 America. 



