PLATE IV. 
Figs. 1—7.—Carbonicola acuta, var. rhomboidalis. Showing the passage from 
a truncate and obtuse posterior end to a beaked and sinuated form. From the 
roof of the Cockshead Seam, Adderley Green, North Staffordshire. My Collection. 
(Page 55.) 
Figs. 8—12.—Carbonicola acuta. To show the eroded umbones. Figs. 8 
and 9 are different views of the same specimen. From the roof of the Cocks- 
head Seam, Adderley Green, North Staffordshire. My Collection. (Page 50.) 
Figs. 183—15.—Carbonicola acuta. A smaller form from the Nether Pit, 
Derbyshire. My Collection. (Page 50.) 
Fig. 16.—Carbonicola acuta. A form with an almost obsolete anterior end, 
? from the Upper Coal-measures of Ayrshire. In the Collection of Mr. Smith of 
Kilwinning. (Page 50.) 
Fig. 17.—Carbonicola acuta. A compressed example from the Coal-measures 
of Coalbrookdale. In the Collection of Professor Prestwich. (Page 50.) 
Fig. 18.—Carbonicola ovalis. The original specimen figured by Sowerby in 
Prestwich’s “Geology of Coalbrookdale,” ‘Trans. Geol. Soc.,’ Ser. 2, vol. v, 
pl. xxxix, fig 13. From the Pennystone beds? Coalbrookdale. In the 
Collection of Professor Prestwich. (Page 56.) 
Fig. 19.—Carbonicola ovalis. A cast of both valves from the Coal-measures of 
Coalbrookdale. In the Geological Collection of the Nottingham Museum. 
(Page 56.) 
Fig. 20.—Carbonicola ovalis. From the Upper Coal-measures of Lanarkshire. 
From the Collection of Mr. J. Nielson, of Glasgow. (Page 56.) 
Fig. 21.—Carbonicola ovalis. From the same locality and Collection. A form 
connecting C. acuta with C. ovalis. (Page 56.) 
Fig. 22.—Carbonicola ovalis. From Butterley, Leicestershire. In the 
Geological Collection of the Nottingham Museum. (Page 56.) 
