DISCINOCARIS OVALIS. 121 



pressure. Black film on black graptolitic shale from Dobbs Linn. Coll. 

 Dairon. 



PI. XVI, figs. 16 a, h. Pyritous film of a similar fossil, also from Dobbs 

 Linn. Geol. Surv. Scotland. M 4269 c and 4270 c. Fig. 16 a gives M 4270 c, 

 being the convex counterpart ; and \Qh shows the traces of a reticulate ornament 

 between the concentric striee (as in Estheriae, &c.), magnified forty diameters. 



PI. XVI, figs. 17, 18, and 19. These are filmy representatives of three 

 individuals in the same schistose-graptolitic shale, squeezed, cleaved, and jointed. 

 They have been pyritous, but are decomposed and partially ochreous ; their present 

 shapes, whether widened or narrowed, are directly due to the force which has 

 compressed and hardened the shale, its crumplings being at right angles to the 

 pressure. 



From the Lower Footbridge, Skelgill; Graptolitic Mudstone, A Z. Coll. 

 Marr. Woodwardian Museum, Cambridge. Fig. 19 is referred to in the ' Report 

 Brit. Assoc, for 1884 ' (1885), p. 94, and ' Geol. Mag.,' 1884, p. 351, as Biscinocaris, 

 sp. nov.; and in the ' Catal. Type Foss.,' Cambridge, 1891, p. 136, as Biscinocaris, 

 sp., from the Coniston Mudstone, Skelgill Beck, Ambleside. 



PI. XVI, fig. 21. A black, strong, shining, imperfect film, in black, finely 

 micaceous shale (with a concave counterpart) ; the edges of the notch are partially 

 overlapped by matrix, giving them a false, sinuous appearance. A fine specimen, 

 and very slightly distorted. The width was probably about 20 mm., and the 

 length about the same. From the Birkhill shales of the Moffat Series at Dobbs 

 Linn. Coll. Lapworth. This is the same specimen as fig. 25 h, pi. 7, ' Proceed. 

 Belfast Nat. Field-Club,' Appendix, 1877. 



PI. XVI, figs. 22 a and h. Delicate pyritous film on black, finely micaceous, 

 graptolitic shale. Much distorted by vertical pressure (another like it lies 

 on the same bed-plane). Fig. 22 h (magnified forty diameters) gives the sub- 

 reticulate and vertically-barred interstitial ornament, like some sculpturing seen 

 among the Estheriae. From Polmoody (see above, p. 114). Coll. D. J. Brown. 



PI. XVI, fig. 23. A rather large, but distorted, pyritous film, imperfect. 

 From the same graptolitic black shale at Dobbs Linn. Coll. D. J. Brown. 



2. DisciNOCAEis OVALIS, sp. nov. Plate XVI, fig. 20. 



This is a small form, with the usual concentric stride, a narrow and deep notch, 

 extending to almost half the length of the test, and a neat oval outline, apparently 

 well preserved, with the wedge-shaped anterior piece in place. Delicate greyish 

 film (once pyritous). 



Measurements : | , 6 mm. ; — , 3 mm. ; A, 4 mm. at 66° ; ,_„ 2 mm. ; 1, 4 mm.; 



V, 50°. 



16 



