130 Lapworth— Graptolites of Co. Down. 



The two preceding species are found in association at Tieveshilly. In 

 Scotland the former appears to be restricted to the Riccarton Beds ( Wenlock) ; 

 and the latter occurs only in the Gala Group (Llandovery). 



19. Sp. 13. Monograptus M'Coj/z. Lapw. Sp. nov. PL 6, fig. 2. 



Polypary simple, monoprionidian, straight, several inches in length, and 

 with an average width of one-sixth of an inch. Hydrothecae about 

 30 to the inch, in contact throughout the whole of their extent, 

 inclined at an angle of 45 ; of the general form of slender quad- 

 rangular tubes, about five times longer than broad ; apertural margin 

 convex, expanded into an oblique, blunt, triangular denticle. (Loc. 

 Builth Bridge, Radnor.) 



The foregoing diagnosis has been drawn up from M'Coy's figure and 

 description of a form from the Silurian Rocks of Wales (Palaeozoic Rocks and 

 Fossils. PI. I B, fig 7, and p. 4) ( I. ) which he erroneously identified with his 

 Graptolithus latus, originally founded upon a fragment of a Dichograptidian 

 species, from the Skiddaw Slates of the Lake District (Quart. Journal Geol. 

 Society, vol. 4, p, 223). Locality — A single well-preserved fragment only has 

 been obtained from the Llandovery beds of Tieveshilly. 



20. Sp. 14. Monograptus Hisingeri, Carr. (See Geo. Mag., 1868. PI. 12, 

 fig. I.) 



(a). Typical form. Locality— Tieveshilly. 



21. (bj. Var. jaculum. Lapw. PI. 5, fig. 20. Localities— Coalpit 

 Bay and Tullygarvan. 



22. Sp. 15. Monograptus cyphus. Lapw. PI. 5, fig. 25. Localities — 



Coalpit Bay and Tullygarvan, 



23. Sp. 16. Monograptus leptotheca. Lapw, PI. 5, fig. 22. Locality — 



Some doubtful fragments only of this species have been collected from 

 the black shales of Coalpit Bay. 



24. Sp. 17. Monograptus concinnus. Lapw. PI. 5, fig. 19. Locality — 



Coalpit Bay. 



(1.) Compare Romer in Leon and Bronn, Jahrbuch f Min., 1855. p. 541, plate 8, fig. 2. 



