No. 8.] J. W. DAWSON — PALEOZOIC LAND SNAILS. 461 



several years ago, but I hesitated to describe it, waiting in hope 

 of additional specimens. As these have not occurred, and I 

 have now carefully examined the whole of the material from 

 these beds, to which I have been able to obtain access, I venture 

 to name it as probably the oldest known land shell, the beds in 

 which it is found being either middle or upper Erian. 



If a land snail, it is larger in size, and probably of a higher 

 type than any of those known from the Coal-formation. This 

 would not be wonderful, when we consider the greater variety 

 of surface and the high character of the vegetation, which, as I 

 have elsewhere endeavored to show, distinguished the later Erian 

 age in north-eastern America. 



Concluding Remarks. 



It may be proper to mention here the alleged Pulmonifera of 

 the genus Palceorhis described by some German naturalists. 

 These I believe to be worm-tubes of the genus Spirorbis, and in 

 fact, to be nothing else than the common S. carhonarius or S. 

 pusillus of the Coal-formation. The history of this error may 

 be stated thus. The eminent paleobotanists Germar, Goeppert 

 and Geinitz have referred the Sph^orbis, so common in the Coal- 

 measures, to the fungi, under the name Gjjromi/ces, and in this 

 they have been followed by other naturalists; though as long ago 

 as 1868 I had shown that this little organism is not only a 

 calcareous shell, attached by one side to vegetable matters 

 and shells of moUusks, but that it has the microscopic structure 

 characteristic of modern shells of this type.^ More recently, 

 Van Beneden, Caeuius and Goldcnberg, perceiving that the 

 fossil is really a calcareous shell, but apparently unaware of the 

 observations made in this country by myself and Mr. Lesque- 

 reux, have held the Sj^irorbis to be a pulmonate mollusk allied 

 to Planorbis, and have supposed that its presence on fossil 

 plants is confirmatory of this view, though the shells are attached 

 by a flattened side to these plants, and are also found attached 

 to shells of bivalves of the genus Naiadites. Mr. R. Etheridge, 

 Jr., of the Geological Survey of Great Britain, has recently 

 summed up the evidence as to the true nature of these shells,. 

 and hns revised and added to the species, in a series of articles 

 in the Geological Magazine of London, vol. viii. 



Acadian Geology, 2ncl edition, p. 205. 



