PRELIMINARY REMARKS. 



The first volume of the present work having been devoted almost entirely to the 

 description and illustration of the Brachiopoda of the Tertiary and Secondary, or 

 Mesozoic series, 1 my second will be appropriated to those of the Permian 2 and 

 Carboniferous periods. 



The Brachiopoda of the Permian system of England are few in number, and have 

 been more completely investigated than those of any of the other epochs : they are, with 

 a single exception, described and illustrated in Professor King's valuable Monograph, 

 issued in 1850 by the Palseontographical Society ; this work being at the same time the 

 largest and most complete that has hitherto appeared on British Permian fossils. 



It may, therefore, be very naturally inquired why I should have taken upon myself to 

 write on a subject apparently so completely investigated ; my excuse must be based 

 upon the necessity I found myself under to combine my series of Monographs by a few 

 pages on the Permians, and especially so as the study of several publications prior and 

 subsequent to 1550, as well as of a vast amount of new and very perfect material in the 

 possession of Messrs. Howse and Kirkby, has made it desirable to propose a few small 

 alterations to the works hitherto published, as well as to offer some additional details and 

 illustrations, which will not, I trust, be considered entirely superfluous. 



1 For hitherto no species belonging to the class have been discovered in any of the Triassic beds of 

 Great Britain, which include the variegated marls, Keuper and Bunter Sandstein. 



2 It will not be necessary to enlarge upon the geology of the group, as this has been done already by 

 different authors, and of which a full account will be found in one of the Society's volumes ; but I will 

 mention the subdivision of the beds, as latterly proposed by Mr. Howse in his valuable paper, published in 

 the ' Annals of Nat. History ' for January, 1857. In the descending order we find — 



1. Upper yellow sandstone . . . .1 



2. Conglobated or Botryoidal limestone . . J 



3. Concretionary or cellular limestone . . ] m - ;mi 



4. Shell limestone (Zechstein dolomit of the Germans J 



5. Magnesian conglomerate . . . "It 



Magnesian 

 limestone. 



6. Compact limestone 



7. Marl slate. 



The Brachiopoda are found in the marl slate, compact limestone, conglomerate, and shell limestone only. 



1 



