20 CARBONIFEROUS LAMELLIBRANCHIATA. 



stated that " the author concludes his memoir with some observations on the 



fossils of eighteen genera of shells which he enumerates, twelve are 



marine." A memoir on the ' Geology of Coalbrookdale/ by Joseph Prestwich, 

 jun., "was commenced" on April 13th, 1836, and concluded on the 27th, 

 ' Proceed. Geol. Soc.,' vol. ii, p. 401. At p. 405 it is stated that " The fossils of 

 the Coal-measures are described with great detail." The paper was not published 

 in the ' Transactions ' of the Society till 1840, when there appeared an Appendix 

 by Mr. J. de Carle Sowerby, describing and figuring the eighteen genera of 

 shells before mentioned. 



Although probably determined in 1834 and 1836, these fossils can be recorded 

 as named only in 1840, according to the rules of nomenclature. There are twenty 

 species of various genera of Carboniferous Lamellibranchs described in the paper ; 

 though, with possibly only two exceptions, the names given to the eight genera 

 therein enumerated can no longer stand on biological grounds. The following 

 marine Lamellibranchs are described and figured : 



Unio Urei. 



— Ansticei. 



— parallelus. 

 Donax? sulcata. 

 Venus ? carhonaria. 



Nucula sequalis. 



— accipiens. 



— acuta. 

 Feet en gentilis. 



— scalaris.^ 



During the years 1834 — 1840 Goldfuss issued, in parts, his great work, ' Petre- 

 facta Germanica.' Unfortunately, though he gives with care the localities whence 

 his types were obtained, it is often very difficult to ascertain from which particular 

 geological formation they were collected. The collection of types is now in the 

 Museum of the University of Bonn. As far as I can make out, about one dozen 

 new Carboniferous Lamellibranchs are figured and described, but several of those 

 of other authors are refigured from German examples. 



1840. Sedgwick and Murchison's paper " On the Physical Structure of Devon- 

 shire, and on the Subdivisions and Geological Relations of its Older Stratified 

 Deposits," was read before the Geological Society on June 14th, 1837, and was 

 published in the ' Transactions of the Geological Society,' vol. v, pt. iii, 1840. 

 It contains six plates of fossils, with descriptions by J. de Carle Sowerby ; the 

 following Lamellibranchs being figured and described : 



Fosidonia lateralis ^ 



— Fgcheri, Goldfuss V From Venn, near Barnstaple. 



— — var. Groldfuss J 



— tuberculata From Budle, Northumberland. 



1 Some other species, referred to Modiola, Mytilus, and Avicula, have been determined as 

 JUaiadites in my previous mouograi)h. 



