Vol. 52.] GEOLOGY OF THE NEIGHBOURHOOD OF CARMARTHEN. 535 



a lower horizon. Further evidence for the Bala age of these beds 

 is the occurrence of Stygina Murchisonce, Murch. For many years 

 Pensarn was the only known locality for this fossil, but it has been 

 found by Messrs. Nicholson and Marr in the Drygill Shales. A 

 large assemblage of fossils from the same district has been examined 

 by Miss Elles and Miss Wood, and they have recently 1 shown that 

 these beds are of Bala age. 



The grits, sandstones, and conglomerates have only yielded a 

 solitary fossil, Holopella, so that we reserve our opinion on the age 

 of this part of the series until we can examine them more fully. 

 In this connexion it is, however, interesting to note that Sir 

 11. I. Murchison considered the ' schists,' grits, and sandstones as of 

 one and the same age ; but he compared them with the slates of 

 Angers, and placed them at the very base of the Llandeilo. 



V. Description of some new Species of Trilobites. 

 Genus Peltura, Milne-Edwards. 



Peltura punctata, sp. nov. (PI. XXVI. figs. 1-10.) 



General form. — Long oval, slightly narrowing towards the posterior 

 end. Very gently convex. Trilobation distinct. 



Head. — Rather more than a semicircle, wider than long ; length 

 about | that of the whole body, surrounded by a narrow raised 

 border, which widens slightly in front of the glabella, where it is 

 ornamented by a row of about twenty puncta placed in a groove. 

 Glabella gently convex, parallel-sided, longer than broad, with two 

 pairs of distinct lateral furrows curving slightly backward, a third 

 anterior pair being sometimes very faintly visible. The second and 

 third pairs of furrows occupy rather more than ^ of the width of the 

 glabella. Axal furrows well marked. The neck-furrow cuts off a 

 wide segment, and extends right across the posterior end of the 

 glabella. The neck-segment is crossed on each side by a sloping 

 furrow, which cuts off a triangular piece as in Peltura scarabceoides. 

 In the centre of the segment is a small tubercle. The fixed cheeks 

 are large, triangular, and gently convex ; the neck-furrow on the 

 cheeks is very near the posterior margin, this furrow is continued 

 round the genal angle and a little way up the side. Free cheeks 

 narrow, generally absent. Genal angles rounded. Eyes small, 

 placed very far forward, just below the punctate border. Palpebral 

 lobe prominent. Ocular ridge distinct on some specimens, but not 

 always well marked off. 



Thorax with twelve segments ; nearly half as long again as the 

 head. Axis wider than the greatest width of the pleura, gently 

 tapering towards the posterior end. In the centre of some of the 

 segments a small tubercle is visible. Pleura nearly straight, sharply 

 elevated as far as the fulcrum, which is placed J or less of the 



1 Miss G. L. Elles and Miss E. M. E. Wood ' On the Drygill Shales,' Geol,. 

 Mag. 1895, p. 246. 



Q. J. G. S. No. 207. 2 o 



