CARBONIFEROUS BRACHIOPODA. 
249 
SUPPLEMENT TO THE BRITISH CARBONIFEROUS BRACHIOPODA. 
The first, second, third, fourth, and fifth parts constituting my Carboniferous Mono- 
:graph were respectively published in April, 1858, November, 1859, March, 1861, 
December, 1861, and May, 1863. 
Although very extensive researches and collecting of specimens have taken place since 
the periods above named, by a number of experienced geologists, eleven species only, 
either new or new to Great Britain, appear to have been discovered, viz. Lingula 
Thomsoni, Dav. ; Biscina Craigii, Dav. ; Athjris 23isum, Dav. ; Sjnriferhia Elheridgei, 
Dav. ; Rhynclionella rejlexa, de Kon. ; Hh. Brocldei/ensis, Dav. ; Rh. Olassi, Dav. ; Camaro- 
phoria Kingii, Dav. ; JRliynchopora Youngii, Dav. ; Productus complectens, Etheridge, junr. 
P. Griffithiamis, de Kon. 
It will, therefore, not be necessary to revise the whole subject in connection with the 
Carboniferous species in this Supplement ; I shall, however, be able to add a good deal 
of useful information respecting some of the species already described in the Monograph, 
and give figures of better examples of several of them ; and this will complete, as far as 
is within my power, the history of the species that lived in the British area during the 
Carboniferous period. 
Many friends have kindly and zealously contributed to the work by affording me 
not only their valuable and valued help, but by undertaking several special investiga- 
tions under favorable circumstances ; and I have endeavoured to reproduce their obser- 
vations as much as possible in their own words. 1 would, therefore, tender my grateful 
thanks to Prof. W. King, D.Sc. ; Prof. Dr. Ij. de Koninck ; Profs. Ramsay and Geikie ; 
Mr. John Young, of the Hunterian Museum, Glasgow ; the Rev. Norman Glass, of Man- 
chester ; Mr. J. Neilson, Mr. J. Thomson, and Mr. J. Armstrong, of Glasgow ; Mr. R. 
Craig, of Beith ; Dr. Rankin, of Carluke ; Messrs. Etheridge, father and son ; Mr. J. Smith, of 
Stobs, Kilwinning ; Mr. J. Aitkin, of Manchester; Mr. J. Wright, of Belfast; Dr. Hunter, 
of Carluke ; Mr. J. W. Kirkby, of Ashgrove ; Mr. A. Somervail, of Edinburgh ; Mr. G. T. 
Whidbourne, of Bristol ; Mr. R. Howse, of Newcastle ; Mr. J. F. Walker, of York ; Mr. 
J. Eckles ; the Rev. W. Downes, of Collumpton ; Mr. Tym, of Castleton, &c. 
The geology of the Carboniferous system has within the last few years received con- 
siderable attention from several able observers, but it will not be possible in this Supple- 
ment to discuss that important subject. A few general observations will, however, be 
necessary. In a letter dated the 5th of April, 1879, Prof. Ramsay, in answer to a 
