ANNIVERSARY ADDRESS OE THE PRESIDENT. 



133 



{Orthoceras arciioliratum, Hall) unites it with the Llandeilo group 

 (and this I believe to be a doubtful species) ; and only 7 connect it with 

 the Lower Llandovery, and 3 of the 7 do not range higher. The 7 

 species are Lituites cornu arietis, Sow., Orthoceras ibex, Sow., 0. 

 vagans, Salt., 0. annulatum, Sow., 0. Barrandii, Salt., 0. politum, 

 M'Coy, and 0. tenuistriatum, Miinst. The 3 species that directly 

 unite the Caradoc and Lower Llandovery are three of the above — 

 0. vagans, Salt., 0. annulatum, Sow., and 0. Barrandii, Salt. 9 

 range to the Upper Llandovery, 4 to the Woolhope, 9 to the Wenlock, 

 and 3 to the Ludlow. These are the appearances of species that 

 ascend through and into the higher formations. 30 of the 47 species 

 are confined to the Caradoc, not ranging higher, whereas 15 species 

 pass to the rocks above. Ireland is represented by 24 of the 47 

 species, 18 of which do not leave the Caradoc horizon, and 17 are 

 strictly confined to the Irish deposits. 



Of the Scotch Caradoc Cephalopoda we only know of 6 restricted 

 species, viz. Orthoceras auclax, Salt., 0. arciioliratum, Hall (also 

 Llandeilo), 0. vaginatum, Schloth., 0. politum, M'Coy, 0. primcevum, 

 Forbes, and 0. tenuistriatum, Miinst. ; and only 15 species out of the 

 known 47 occur in the Scotch rocks. 



Geographical Distribution. 



I have now to treat of the geographical distribution of the 

 extensive series of species occurring in the Caradoc and Bala rocks, 

 the large fauna (614 species) being an additional reason for so doing, 

 more especially considering the widely spread area occupied by the 

 Lower and Middle Bala groups. It would be impossible to give all 

 the localities whence our knowledge of their distribution has been 

 derived ; but the chief in North Wales number between 30 and 40, 

 and in South Wales about 10. The Shropshire and Westmoreland 

 localities are less numerous, but are prolific in species. 



The following 10 areas, including about 50 localities in the British 

 Islands, have yielded the 613 species known. Their occurrences or 

 appearances number 1555. 



Caernarvonshire 105 species, distributed in 10 chief localities. 



North 

 Wales. 



South 

 Wales. 



England. 



Scotland 

 Ireland 



Denbighshire 131 



Montgomeryshire 138 



Merionethshire 162 



Pembrokeshire 93 



Caermarthenshire 72 



f Shropshire 123 



\ Westmoreland 123 



302 



306 



6 

 5 

 10 

 5 

 5 



1555 



The actual number of species (so far as we know) occurring in 

 North Wales is 270, in South Wales 134, in Shropshire 123, in 

 Westmoreland 123, in Scotland 302, and in Ireland 306. 



The intimate relation of the Caradoc to the succeeding Lower 

 vol. xxxvn. I 



