Section IV., 1909. [ US ] Trans. R. S. C. 



VIII. — Remarkable Forms of the Little River Group, 



By G. F. Matthew, D.Sc. 



PHYLLOPODA. 



Leaia silurica n. sp. Plate IV, Fig. 3. 



(Read May 26, 1909.) 



Outline of the valves subquadrilateral. Hinge-line about as long as 

 the height of the valve. Valve divided into three areas by two sharp 

 radiating ridges. The ventral area is the largest and is about as wide as 

 high ; it is slightly arched below and bluntly rounded at the apex ; botii 

 it and the posterior area are marked by about eight (8) transverse, 

 rounded ridges, that terminate against the bounding ridges of these 

 areas. The posterior area is longer than wide and is acutely triangular 

 at the apex ; it is bordered along the hinge-line by a row of faint tuber- 

 cles, placed opposite the furrows that come between the transverse ridges 

 of the area. The anterior area is twice as long as wide and is rounded 

 in front, where there is a weak border fold; it shows scarcely any trans- 

 verse ridges. 



Length, 6i/^ mm. Width, 5 mm. 



Horizon and Locality. Lower Cordaite Shales (black shale beneath 

 Hartt's Bed No. 2?) Fern Ledges, Lancaster, N.B. Found by Mr. 

 Wm. Mcintosh. 



T think it not improbable that the " trilobite " collected from Bed 

 No. 2 by Mr. Wm. Payne ^ may have been a valve of this species. 



This species is allied to L. Leidyi of the Coal-measures of Penn- 

 sylvania,2 but has fewer concentric ridges, the apex of the ventral area 

 also is broader, and the valves of this species are tuberculated along the 

 hinge-line, whereas those of L. Leidyi are tuberculated along the two 

 ridges that extend to the ventral margin, dividing the three areas of 

 the valve. 



From the situation in which this fossil was found it seems probable 

 that it inhabited fresh water ponds. 



MERISTOMATA. 



Provisionally we place here an arthropod which seems by the form 

 to be related to Belinurus, but which we have no reason to think was 



1 Acad. Geol., 2nd Ed.. 1868, p. 519. 



«Traite Palfeon. Zittel. Vol. II, p. 566, fig. 775o. 



