BIBLIOGRAPHICAL SKETCH. 19 



gave the name Posidonia Becheri to a certain Coal-measure shelL Later on, in 

 1835 — 1837, in his ' Lethaea Greognostica,' finding that the name Posidonia had been 

 given to a genus of plants, he considered it inadmissible for a genus of shells, and 

 substituted the name Posidonomya, and refigured P. Becheri, together with 

 Pterinea Isevis, Gardium elongatum, and Hippopodium ponderosum, the last being 

 probably erroneously stated to belong to the Carboniferous strata. In the ' Index 

 Palgeontologicus ' of the same author, published in 1848, lists of the known 

 Carboniferous Lamellibranch fossils are given. 



In 1836 Professor John Phillips published his great work on the "Mountain 

 Limestone District," being Part II of ' Illustrations of the Geology of Yorkshire.' 

 In this volume are described fifty-six species belonging to eighteen genera of 

 Lamellibranchiata from the Carboniferous beds of Derbyshire, Yorkshire, and 

 Northumberland, of which forty-nine species are described and figured as new ; but 

 one of these, Pinna costata, is said to be " probably the species figured by Martin 

 under the names of Pinna flahellif or mis and P. nuda." 



Many of the type specimens are fortunately preserved in the " Gilbertson 

 Collection " of the Natural History Museum at South Kensington, but a few are 

 in the Museum at York, and others have completely disappeared.^ Under such 

 circumstances tliere is great difiiculty in arriving at a conclusion as to which 

 shell is supposed to be represented by the figure, owing to the meagre descrip- 

 tions and the poorness of the plates ; and it would appear that individual figures 

 are often a compound of several views from different aspects of the same shell. 

 This work is of the highest importance in the history of Carboniferous palgeonto- 

 logy ; previous to its issue only about twenty-three species belonging to fourteen 

 genera of marine Laraellibranchs had been recorded, and the majority of the 

 genera and species are still accepted. 



1836. Dr. E,hind, in his ' Excursions Illustrative of the Geology and Natural 

 History of Edinburgh,' gave a note at p. 143 of the occurrence of " two species 



of Testacea. One of these is decidedly a Mytilus ; the other species 



resembles the Mactra suhtruncata " in shale at Woodhall, Water of Leith. 



In 1838 the same author, in a little book entitled ' The Age of the Earth,' gave 

 a plate with four Unios from the Coal-measures of Polmont, and Axinus Pent- 

 landicus and a Modioliform shell from Woodhall, Water of Leith, now recognised 

 as a dwarfed form of Naiadites crassa. 



On February 5th, 1834, Prof, (now Sir) J. Prestwich's paper on the ' Faults 

 which affect the Coal-field of Coalbrookdale ' was read before the Geological 

 Society of London, and in the ' Proceedings of the Geol. Soc.,' vol. ii, p. 20, it is 



' It is believed that, on Prof. Phillips's arrival in London by coach, from York on his way to 

 Oxford, one of his boxes of foss^ils was stolen at the Bell Savage Yard, and the stones, not being of 

 value to the thieves, were thrown over Blackfriars Bridge. 



