26 CARBONICOLA, ANTHRACOMYA, AND NAIAD1TES. 



Naiadites (Anthracoptera) carbonaria, Dawson. 

 „ ,, IcBvis, Dawson. 



„ {Anthracomya) elongata, Dawson. 

 „ arenacea, Dawson. 



Naiadites ovalis, Dawson. 



„ angwlata, Dawson. 



„ obtusa, Dawson. 

 Anthracosia Bradorica, Dawson (p. 314). 



I have, by the kindness of Sir W. J. Dawson, been allowed to examine a 

 series of his specimens, and the result appeared in a joint paper before the 

 Geological Society of London (read February 21st, 1894), ' Quart. Journ. G-eol. 

 Soo.,' vol. L, pp. 435—442, 1894. 



1861. In 1861 appeared the first edition of Hull's ' Coal-fields of Great 

 Britain,' which contained one plate, of which fig. 1 is said to be Anthracosia 

 robusta ; and in a very brief reference to the Mollusca, pp. 40 and 43, under the 

 names Anthracosia (Unio of early authors) and Modiola, a few words are said as to 

 the marine or brackish water habitat of these forms. 



In later editions, 1873 and 1881, the original plate was done away with and a 

 new one (to face p. 38) given, with Anthracomya carinata (sic, for Anthracoptera 

 carinata), Anthracosia centralis, and A. aquilina. 



Prof. Hull's views as to the habitat of these shells appears to have somewhat 

 changed; he says, "Anthracosia (Unio), Anthracomya, and Anthracoptera, capable 

 apparently of living in fresh-water lakes or brackish water estuaries." 



A very valuable paper by the same author, bearing very little on the shells 

 themselves, from which I have quoted freely above (pp. 2, 3), appeared in the 

 * Quart. Journ. Geol. Soc.,' vol. xxxiii, 1877, p. 613, &c, " On the Classification 

 of the Carboniferous Series;" but I doubt whether any evidence which he has 

 adduced on the strength of the shells in question is of much value, owing to the 

 great confusion which has existed up to the present time with various authors as 

 to the generic characters of the various forms. 



1856-63. The first memoir of Mr. Salter which I can find on this subject, to 

 which he paid some attention, appeared in 1860 as the " Memoir of the Geological 

 Survey," 'The Iron Ores of Great Britain,' Part I, 1856. 'The Iron Ores of 

 the North and North Midland Counties ' contains only the casual remark 

 that certain beds at Chesterfield (" dog-tooth rake ") " are almost made up 

 of fossil bivalves (Anthracosia)," which he refers to Unio agrestis of Brown. 

 He says that the " Wallis rake " at Codnor Park, Butterley, is full of the same 

 shell. 



1861. In Part III, ' The Iron Ores of South Wales,' in 1861, he enters more 

 fully into the subject, and gives the diagnosis of his new genus Anthracomya, 

 describing and figuring — 



Anthracomya Adamsii. 

 „ pumila. 



Anthracomya subcentralis. 

 senex. 



