A MONOGRAPH 



OF THE 



BRITISH FOSSIL BMCHIOPODA. 



PART VIL 



THE SILURIAN BRACHIOPODA. 



BY 



THOMAS DAYIDSON, F.R.S., F.G.S., &c. 



WITH 



OBSEEYATIONS 



ON THE 



CLASSIFICATION OF THE SILURIAN ROCKS: 



BY 



SIR UODERICK IMPEY MURCHISON, Bart., 



K.C.B., D.C.L., M.i., F.E.S., E.G.S., 



DIEECTOR-GENEEALOr THE GEOLOGICAL STJEVET OF GEEAT BRITAIN AND IRELAND; PRESIDENT OF THE EOYAL GEOGRAPHICAL 



SOCIETY OF LONDON ; TEUSTBE OF THE BRITISH AND HUNTEEIAN MUSEUMS, AND OF THE BRITISH ASSOCIATION 



FOR THE ADVANCEMENT OF SCIENCE ; CORRESPONDING MEMBER OF THE INSTITUTE OF FRANCE ; 



MEMBER OF THE IMPERIAL ACADEMY OF SCIENCE, AND GEOGRAPHICAL SOCIETY OF 



ST. PETERSBURG ; HON. MEMBER OF THE EOYAL ACADEMIES OF BERLIN, 



COPENHAGEN, STOCKHOLM, BRUSSELS, MUNICH, HOLLAND, 



TURIN, ETC. 



LONDON : 



PRINTED FOR THE PALtEONTOGRAPHICAL SOCIETY. 



1866—1871. 



