Yol. 67.] FAUNAE HORIZONS IN THE BRISTOL COALFIELD. 325 



preserved, and show the essential characters of the species. The 

 best example is that of the left valve with a well-marked and 

 perfectly straight hinge-line. The umbo is small and crushed, and 

 does not overlap the hinge-line. The anterior valve-margin is 

 almost truly semicircular, the ventral margin being broadly rounded, 

 and passing directly into the more broadly rounded posterior margin 

 which curves upwards and forwards to the hinge-line. Traces of 

 numerous fine concentric lines of growth are present on the margin 

 of the valve, the inner portion being almost smooth, and marked 

 with what appears to be a faint reticulation. The free margin of 

 the valve is somewhat inflected along its whole length. 



Horizon and locality. — Roof -shales over the High Vein, 

 Coalpit Heath. Estheria cf. tenella (?) occurs at 'Horizon 3' 

 between the Ashton and Bedminster Great Veins, South Liberty 

 Colliery, Bristol. (See PL XXVII, fig. 3.) 



Estheria sp. 



A few examples of a smaller species of Estheria occur in the 

 same shale as the last, but are specifically indeterminable. 



Horizon and locality. — Roof-shales over the High Vein, 

 Coalpit Heath ; and at 276 feet below the Bedminster Great Vein, 

 South Liberty Colliery, Bristol. 



Bairdia cf. ampla? (Reuss). (PI. XXVII, fig. 4.) 



Certain elongate oval shells are referred to the genus Bairdia. 

 They are 6 millimetres long and 3 mm. broad. Each valve is 

 flatly convex, broadest in the middle part of the length, and closely 

 applied along the margin to the opposite valve. Xo trace of a hinge- 

 line or of lines of growth can be distinguished. The surface of each 

 valve is crossed by three vertical, bluntly-rounded ridges which do 

 not reach the dorsal or ventral margins. In two specimens where 

 one valve has been crushed into the interior of the other, the 

 vertical ridges stand out in higher relief. 



Horizon and locality. — 276 feet below the Bedminster 

 Great Vein, South Liberty Colliery, Bristol. 



Leaia leidyi Lea, var. salteriana Jones. (PI. XXVII, figs. 5 & 6.) 



During Mr. D. G. Lillie's investigations of the fossil flora of 

 the Bristol Coalfield, 1 he found upon the spoil-heap at Coalpit- 

 Heath Colliery a small quantity of black shale containing fossils 

 new to him : these he kindly placed at my disposal, A subse- 

 quent visit to the colliery resulted in the finding of many more, 

 and it became clearly evident that a well-defined faunal horizon 

 existed in the Coal-Measures at this colliery. Examination of the 

 shale showed that it contained abundant fine examples of the 

 usually rare phyllopod, Leaia leidyi var. salteriana, associated 



1 ' Notes on the Fossil Flora of the Bristol Coalfield ' Geol. Mag. dec. 5 

 vol. vii (1910) p. 58. 



