PLATE II. 



Didy mograptus — continued. 



FIGS. 



1 a, b. — Didymograptus affinis, Nich. 



1 a. Showing proximal end and one stipe. Outerside. Skiddaw Slates. British Museum 

 (Natural History), S. Kensington. 



I b. Reverse view. Ibid. 

 2. — Didymogra})ti(s gracilis, Toruq. 



Obverse view. Barf. Skiddaw Slates. Mr. Postlethwaite's Collection, Keswick. 

 8 a — d. — Didymognijitus acufidens, Lapw., MS. 



3 a. Obverse view. Figured by Hopkinson as D. affinis. Quart. Jovu-n. G-eol. See., 1875, 



pi. xxxiii, fig. 6 b. Porth-hayog, Ramsey I. Up. Areuig. Woodwardian Museum. 

 3 b. Isolated stipe. Porth-hayog. Up. Arenig. Miss Wood's Collection. 

 3 c. Isolated stipe. Hope Stream, a little west of Hope Quarry, Shropshire. H.M. 



Geol. Survey Collection. 



3 d. Ibid. 



4 a — c. — Didymograjdus Nicholsoni, Lapw. 



4 a. Obverse view, preserved as a east. Barf. Skiddaw Slates. Woodwardian Museum. 

 4.b. Ibid. 



4 c. Preserved in shale. Figured by Hoi^kinson and Lapworth, Quart. Journ. Geol. Soc, 



1875, pi. xxxiii, figs. 5 a — d. Llanvirn Quarry. Up. Arenig. Woodwardian Museum. 



5 a, b. — Didy mograptus Nicholsoni, var. planus, EUes and Wood, nov. 



5 a. Obverse view. Outerside. Skiddaw Slates. Woodwardian Museum. 



5 b. Isolated stipe. Ibid. 



6 a, b. — Didy mograptus simulans, EUes and Wood, sp. nov. 



6 «. Reverse view, preserved as a cast. Barf. Skiddaw Slates. Woodwardian Museum. 



6 b. Obverse view, preserved partly as a cast, partly in relief. Ibid. 



7 a, b. — Didymograptus serratulus, Hall. 



7 a. Reverse view, showing long nema. Minnoch Water, Gleucaird Loilge, S. Scotland. 



Grleukiln Shales. Museum of Geol. Survey of Scotland, Edinburgh. 



7 b. Isolated curved stipe. Biruock, S. Scotland. Glenkiln Shales. Lapworth's Collection, 



Birmingham. 



8 a — c. — Didymograpt ns fasciculatus, Nich. 



8 a. Isolated stipe, a cast. EUergill. Up. Skiddaw Slates. Lapworth's Collection. 

 8 b. Ibid. 



8 c. Proximal end, badly pi-eserved. Thornship Beck. Up. Skiddaw Slates. British 



Museum (Natural History), S. Kensington. 



9 a — e. — Didymogrnptns gibbentlux, Nich. 



9 n. Showing widely divergent stipes. Randal Crag. Skiddaw Slates. Postlethwaite's 



Collection. 

 9 6. More convergent type. Figured by Nicholson, Ann. Mag. Nat. Hist., 187-5, pi. vii, 



fig. 3. Kandal Crag. Skiddaw Slates. Woodwardian Museum. 

 9 c. Reverse view, showing nema. Figured by Salter as D. caduceus. Quart. Journ. Geol. 



Soc, 1863, p. 138, fig. 13 rt. Longside, Keswick. Skiddaw Slates. Museum of 



Practical Geology, Jt-rmyii Street. 

 9 d. Small form with long nema. Figured in Ann. Mag. Nat. Hist., 1875, pi. vii, fig. 3 b. 



White House Fell. Skiddaw Slates Woodwardian Museum. 

 9 e. Small form, showing nema. Figured by Hopkinson as Phyllograptus stella, Quart. 



Journ. Geol. Soc, 1875, pi. xxxiv, fig. G. 



10 a, b. — Didymograptus v-fractvs, Salt. 



10 (/. Obverse view. Buttermere. Skiddaw Slates. Lapworth's Collection. 



10 b. Reverse view. Ibid. 



11 a, b. — Didymograptus, var. volucer, H. O. Nich. 



II a. Poorly preserved, all details indistinct. Figured, H. O. Nicholson, Geol. Mag., 1890, 



p. 342, fig. 3. Outerside. Skiddaw Slates. 



11 b. Reverse view. Sldddaw. Museum of Pract. Geol., Jermyn Street. 



12 a — f. — Didymograptus deflexus, EUes and Wood, sp. nov. 



12 a. Reverse view. Figured by EUes as D. v-fractus. Quart. Journ. Geol. Soc, 1898, 



p 508, fig. 25 a. Barf. Skiddaw Slates. Woodwardian Museum. 

 12 b. Obverse view. Ibid., fig. 25 b. 

 12 c. Long specimen. Skiddaw Slates. Museum of Prait. Geol., Jermyn Street. 



