Lohley — Distribution of British Brachiopoda. 501 



Procccdinf^ now to the consideration of the range and distribution 

 of the nine families in which all the British fossil Brachiopoda may 

 be placed, we find that nearly every family has had a long range in 

 time, and that six are represented by recent species. 



The following table shows the number of species of each family 

 in each System or principal group of British strata. 



Families. 



1 



6 



1 



i 

 I 



o 



1 



1 



.2 



6 



.2 



*-> 



1 



1 



S 



u 



"S 



Lingulid(C 



Biscinidce 



Strophomenidcc . 



Craniadce 



Spirifcridcc 



Rhynchonellidai. 



Froductidce 



Terebratulidcs... 



Thecididce 



Class — 

 Brachiopoda.... 



1+1? 

 ? 



31i-3v. 

 15 



81+7v. 



7 

 29+5V. 

 29 



3 



1 



1 



16 



41-4-lv. 

 18+lv. 



8 



6 



6 



2 



9 



3 

 45+lv. 

 19 

 48 



3+lv. 



1 



1 



1 



1 



5 



3 



4+3V+? 



1+lv. 



... 



2 



7 

 7 

 7 

 8 

 37 



59 

 14 



2 

 ? 







4 



i7+4v. 



45+3v. 



1 



2 



1 



r 



5* 



'* 



1+2? 



185+15V. 



91-4-2V. 



135+2V. 



17+4V+? 



14169+7V+?, 9 



* 



The family of Froductidcd, represented by the Chonetes in the Lland- 

 overy rocks, greatly abounding in the form of Produdus in the 

 Carboniferous Limestone, dies out in the Permian, and is therefore 

 a characteristically Palasozoic family. 



Thecididce, on the other hand, are characteristically Mesozoic, as they 

 have not hitherto been found in strata older than the Middle Lias, or 

 newer than the Chalk. We thus have one family essentially Pala30- 

 zoic and one family characteristic of Mesozoic strata. Having no 

 genus we have no family confined to Cainozoic strata, each great 

 type of form in the Brachiopoda having come into existence long- 

 previously, the latest family being the Thecididce. 



Although not entirely confined to Palseozoic strata, the family of 

 Strophomenidce may almost be said to be characteristic of these rocks, 

 since it is so largely represented in the strata below the Coal, and 

 is only found in rocks newer than the Permian represented by a few 

 species of one genus, Leptcena, found in the Lias. 



Spiriferida, too, are very largely represented in Palseozoic strata, 

 and very sparingly in Mesozoic, eight species only having been 

 discovered in strata above the Permian. 



The families which range from the Palaeozoic rocks to the present 

 time, and now represented by living species, are Lingididcc, Biscinidce, 

 Craniadce, Bhijnchonellidce, and Terebratididce. 



Of these the first, Lingulidce, as we have before seen, is the oldest 

 of all the families of Brachiopoda, and has been found in nearly 

 every group of rocks from the Cambrian to the Eocene, though repre- 

 sented by very few species in any, the greatest number of species of 

 Lingulidce being found in the Primordial Silurian rocks, in which not 

 more than ten well-defined species have hitherto been discovered. 



