PLATE VI. 



TetragraptuS (continued) and SchizOgraptuS, Nicholson. 



FIGS. 



1 a, b. — Tetragraptvs Posflethwaiti, Elles. 



1 a. Typical form, reverse view. Figured, Elles, Quart. Journ. Geol. Soc, 1898, vol. liv, 

 p. 492, fig. 14 b. Carlside Edge. Skiddaw Slates. Postlethwaite's Collection. 



1 b. Incomplete specimen, showing only three stipes. Ibid., fig. 14 c. 



2 a, b. — Tetragraptus fruticostis (Hall). 



2 a. Fragment, obverse view. Bennane Head, Ballantrae. Lapworth's Collection. 



2 b. Another fragment. Ibid. 



3 a — d. — TetragraptuS pendens, Elles. 



3 a. Long specimen. Figured, Elles, Quart. Journ. Geol. Soc, 1898, vol. liv, p. 491, fig. 13. 



Barf. Skiddaw Slates. Postlethwaite's Collection. 

 3 h. Ibid., fig. 13, op. cit. 

 3 c. Ibid., fig. 13, op. cit. The three foregoing specimens are preserved upon the same slab. 



3 d. Eeverse view, specimen preserved as an impression. Barf. Skiddaw Slates. Postle- 



thwaite's Collection. 



4 a — ■/. — TetragraptuS serra (Brongniart). 



4 a. Large form, preserved partly as a cast, partly as an impression. Great Knot, Kandal 



Crag. Skiddaw Slates. Woodwardian Museiun. 



4 b. Specimen preserved as an impression, showing sicTila. Kandal Crag. Skiddaw Slates. 

 Woodwardian Museum. 



4 c. Compressed specimen. Figured by Hopkinson as T. HalU, Quart. Journ. Geol. Soc, 

 1875, vol. xxxi, pi. xxxiii, fig. 11 a. Whitesand Bay. Middle Arenig. Wood- 

 wardian Museiun. 



4 d. Ibid., fig. 11 b, op. cit. 



4 e. Specimen showing two stipes only. Carlside Edge. Skiddaw Slates. Postlethwaite's 



Collection. 

 4/. Nara'ower fomi. Outerside. Skiddaw Slates. British Museum (Natural History), 

 S. Kensington. 



5 a — e. — TetragraptuS reclinatus, Elles and Wood, sp. nov. 



5 a. Two specimens in association. Whinlatter. Skiddaw Slates. Postlethwaite's 



Collection. 

 5 b. Reverse aspect of 5 a, showing form of thecse. 

 5 c. Two specimens in association. Eandal Crag. Skiddaw Slates. Postlethwaite's 



Collection. 

 5 d. Distorted specimen. Carlside Edge. Skiddaw Slates. Fitz-Park Museum, Keswick. 



5 e. Specimen showing sicula. On same slab as 5 d. 



6 a — e. — TetragraptuS Bigsbyi (Hall). 



6 a. Specimen presenting the typical form. Skiddaw Slates. Lapworth's Collection. 



6 b. Form showing sicula, preserved as an impression. White Horse Fell. Skiddaw 



Slates. Woodwardian Museum. 

 6 c. Well-preserved specimen ; an impression. Bassenthwaite Sand-beds. Skiddaw Slates. 



Woodwardian Museum. 

 6 d. Specimens with stipes distaUy overlapping or conjoined. Troutbeck Beck. Skiddaw 



Slates. Lapworth's Collection. 

 6 e. Ibid. 

 7. — Schizograptus reticuJatus, Nicholson. 



Type specimen. Figured, Nicholson, Quart. Journ. Geol. Soc, 1868, vol. xxiv, pi. v, fig. 4. 



Scale Hill, Crummock. Skiddaw Slates. British Museum (Natural History), S. 



Kensington. 

 8. — Schizograptus tardlfurcatus, EUes. 



Type specimen. Figm-ed, Elles, Quart. Journ. Geol. Soc, 1898, vol. liv, p. 481, fig. 7. 



Carlside Edge. Skiddaw Slates. Postlethwaite's Collection. 

 9. — Schizograptus or Trochograptus. 



Type specimen of Nicholson's Pleurograpttis vagans, Nich., Quart. Journ. Geol. Soc, 1868, 



vol. xxiv, pi. vi, figs. 4, 5. Scale Hill, near Cinimmock. Skiddaw Slates. Postle- 

 thwaite's Collection. 



