EXPLANATION OF THE TABLES AND LIST OF LOCALITIES. 



The Carboniferous system occupies so large an area in Great Britain, that it appeared 

 desirable to tabulate the amount of work done in collecting its Brachiopoda, and 

 to correctly define our present knowledge with reference to their distribution. The labour 

 required to effect this object has been very great ; and although the results are no doubt 

 far from complete, or entirely satisfactory, my tables will, I trust, serve as a groundwork 

 to which may be hereafter added the fruit of further search in the various counties there 

 inscribed. 



When my tables had been almost completed, Mr. Salter suggested, that instead of 

 counties, it might be preferable to divide Great Britain into Carboniferous districts, 

 and to give the range of species in them, including in these districts the Carboniferous 

 Limestone, Millstone-grit, and Coal, somewhat as follows : 



1, The Scotch Basin ; 2, Northumberland, Durham, and north of the Tees (the line 

 of the Eden and the Tees forming a good boundary to separate from No. 2) ; the 3rd, or 

 Yorkshire and North Lancaster, as far south as Wharfedale ; 3a, Cumberland or White- 

 haven ; 4, Derbyshire, with what are called the Yorkshire and Lancashire Coal-fields on 

 each flank ; 5, North Wales and Anglesea ; 6, Shropshire and the Forest of Wyre, Staf- 

 fordshire and Leicestershire patches; 7, South Wales Basin; 8, Forest of Dean, Bristol, 

 and the Mendips; 9, Devonshire; 10, Isle of Man ; 11, Ireland; the last also being 

 similarly divided. 



I should have preferred arranging my tables into such natural boundaries ; but besides 

 certain difficulties, it would have necessitated another kind of research, as for many months 

 previous I had been arranging the species in their respective counties, and which for 

 practical purposes may not be devoid of utility. 



In preparing these tables, and the following lists of localities, no trouble has been 

 spared, for in addition to my own personal researches, which have extended over five years* 

 I have availed myself of all the assistance that could be obtained. 1 



1 Mr. Salter and Mr. Etheridge placed the Geological Survey manuscript lists and specimens before 

 me, and kindly assisted with their personal observations; Mr. ^ aterhouse and Mr. S. P. Woodward, with 

 their usual urbanity and desire to turn the national collection to public use, afforded me every facility 

 to examine at leisure all the Carboniferous species in the British Museum, where Gilbertson's and 

 Sowerby's original collections are now carefully preserved. The Geological Society's stores were also 

 examined, as well as the collection made by the late Mr. D. Sharpe, and I have had the loan of thousands 



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