CRITICAL BIBLIOGRAPHY. 13 



and I am the more inclined to this view from the examination of a specimen from 

 that locality in the possession of Dr. John Young, Curator of the Hunterian 

 Museum, Glasgow. About the figures, pi. xvi, figs. 5, 6, I must say I have great 

 doubt as to the shells they are intended to represent. Ure says, " Two species of 

 mussel are found in Kilbride : those of the former are casts and rare ; the latter 

 are in ironstone and lie flat." The former is possibly Naiadites, the latter 

 Lingula. He figures on pi. xv, fig. 2, a shell which more closely resembles 

 Anthracosia robusta than anything else I know, of which he says, " The cockle 

 is found very perfect in schists with Orthoceras, Encrinites, &c, at Black Craig 

 and Thornley Bank." I have, however, never known G. robusta to be associated 

 with marine forms in Scotland, and Mr. James Nielson tells me that Carbonicola 

 robusta never occurs in this locality. 



1809. The next to write on the subject appears to have been W. Martin, who 

 brought out his ' Petrefacta Derbyensia ' in 1809 at Macclesfield; and, although 

 holding somewhat curious views of the true import of fossils, yet he was endowed 

 with an acute observation. His figures and description are excellent ; and his 

 work is still a standard reference as containing the first descriptions and figures 

 of many Carboniferous Limestone species. He seemed to consider that each 

 fossil species was but the representation in stone of living forms, as is shown in 

 his description, where he states, " The hinge (visible only in recent species), &c." 

 He figures three specimens from ironstone, and I feel no doubt as to the form 

 represented. The name " Conchyliolithus (Mya ovalis) " is given to it. It is here 

 to be noted that the Mya of Linnaeus equals Unio of Lamarck. 



1813. Sowerby, in 1813, published the vol. i of his 'Mineral Conchology,' 

 containing a plate of Coal-measure shells, tab. xxxih, figs. 1 — 3, 5 — 7, with short 

 descriptions, pp. 83, 84, under the names Unio sub constr ictus and U. acutus. The 

 other figure on this plate (fig. 4) is said to have been obtained from marl at 

 Felmersham, Bedfordshire, an Oolitic locality. I have examined the original 

 specimen in the Sowerby Collection in the British Museum (Natural History), 

 South Kensington, and, from the matrix and characters, consider it to be a 

 well-known Oolite shell ; but, curiously enough, this Oolite shell, called Unio 

 uniformis, was considered by Sowerby to be the same form as Martin's Mya ovalis 

 from the Coal-measures of Derbyshire, and the name was substituted because the 

 former was in use for recent shells. 



1824. Defrance, in the ' Dictionnaire des Sciences naturelles,' vol. xxxiii, 

 p. 295, in 1824 followed Sowerby, but suggested that, as nothing of the interior 

 was known, the genus was doubtful, and that the various forms described were 

 simply variations. 



1828. Fleming, in his 'History of British Animals,' 1828, quotes Unio acutus, 

 Sow., giving, however, the locality as Middle Oolite, and Unio Urii, referring 



