The Canadian naturalist and quarterly journal of science . ect specimens which can be disengagedfrom the matrix, are comparatively few. They have been foundin erect SigiUarice and also in a bed of shale. The lowest andhighest beds in which they occur are separated by 2,000 feet ofvertical thickness of strata, including no less than thirty-fivebeds of coal and many underclays supporting erect trees, so thatthe species must have inhabited the locality for a very long timeand must have survived many physical vicissitudes. The first specimen, which was also the first known Paleozoicland shell, was
The Canadian naturalist and quarterly journal of science . ect specimens which can be disengagedfrom the matrix, are comparatively few. They have been foundin erect SigiUarice and also in a bed of shale. The lowest andhighest beds in which they occur are separated by 2,000 feet ofvertical thickness of strata, including no less than thirty-fivebeds of coal and many underclays supporting erect trees, so thatthe species must have inhabited the locality for a very long timeand must have survived many physical vicissitudes. The first specimen, which was also the first known Paleozoicland shell, was found by Sir Charles Lyell and the writer in1851, in breaking up the contents of an erect tree holding rep-tilian bones. The specimens obtained from this tree havingbeen taken by Sir Charles to Cambridge and submitted to thelate Prof. Jeffries Wyman, the shell in question was recognizedby him and the late Dr. Gould, of Boston, as a land shell. Itwas subsequently examined by M. Deshayes and Mr. Gwyn No. 8.] J. W. DAWSON—PALEOZOIC LAND SNAILS. 1. 2. 453. Fig. 1, Pupa vetusta, magnified 8 times lineally ; 2, same, showingthe aperture, X 8 ; 3, same, nuclear whorl, x 25 ; 4, same, mature eggand embryo shell, X 25 ; 5, 6, Pupa Bigsbii, X 8 ; 7, Pupa VermilionensisX 8 ; 8, same, showing aperture, X 8, the small tooth on the colu-mella somewhat exaggerated ; 9, same, section of aperture, showingtooth X 16 ; 10, Zonites prisons, X 8 ; 11, same, crushed specimen,showing aperture x 20. 454 THE CANADIAN NATURALIST. [Vol. ix, Jeffries, who concurred in this determination ; and its micro-scopic structure was described by the late Prof. Quekett, ofLondon, as similar to that of modern land shells. The sioo-lespecimen obtained on this occasion was somewhat crushed anddid not show the aperture. Hence the hesitation as to itsnature, and the delay in naming it, though it was figured anddescribed in the paper above cited in 1852. Better specimensshowing the aperture were afterward obtained by t
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