358 Prof. T. Biqjert Jones and James W. Kirhhy — 



or less high, than the posterior half, and agrees very well with the 

 var. acuta of L. Okeni, as described by us in the Ann. Nat. Hist. 18G5. 

 We have only seen a single example of this form, which is from 

 the so-called " Cypris-shale " of the Joggins Coal-measures. 



4. — Betrichia Nova-scotica, sp. nov. Plate XII. Figs. 5 and 6. 

 Beyrichia, Dawson, Acadian Geology, 1868, p. 256, fig. IBc. 



Tliis BeyricMa is found along with the two first-noticed forms of 

 Leperditia, in the shale from the Lower Coal-measures of Horton. 

 Its resemblance to D'Eichwald's B. coUiculus and B. gibberosa is 

 such that we have been disposed to refer it to them, which belong 

 probably to one species. But the want of authenticated examples 

 of these Eussian forms for comparison, together with certain dif- 

 ferences shown by D'Eichwald's figures from the form under notice, 

 have led us to look upon the latter as undescribed. 



The two valves figured are not exactly alike in outline ; and it is 

 probable that in Fig. 5 the posterior extremity is not perfect where 

 it sweeps down to the ventral margin. 



In Fig. 6, which represents a left valve, the dorsal line is seen to 

 be straight and the anterior extremity narrower than the posterior, 

 this is a generic feature in Beyrichia. The anterior extremity projects 

 only a little way beyond the dorsal line or margin, and then curves 

 rapidly backwards and passes into the evenly convex ventral margin ; 

 the posterior extremity is boldly rounded. The valve is divided 

 into four bosses, lobes, or elongated, protuberant areas, by deep 

 sulcations or depressions. The two uppermost swellings, which are 

 submedial in position, are the most round and boss-like ; behind and 

 below the more posterior boss is an elongate, curved swelling ; and 

 another, similar, but smaller, lies in advance, parallel to the margin 

 of the antero- ventral curve. A narrow, depressed area, follows the 

 course of the free margins, and separates them from the main and 

 convex portion of the valve. Surface apparently smooth. Length 

 varying from -gV to xr inch in length. 



5. — Beyrichia or Primitia ? sp. Plate XII. Fig. 7. 



From the Lower Coal-measures of Horton we have seen the single 

 specimen here figured. It looks very much like a little Primitia, 

 with central sulcus and an elevation on each side, one of which has 

 been either broken in or bears a small central depression instead of 

 a terminal tubercle. It may be an undeveloped form of Beyrichia. 

 About iV inch in length. 



6. — Carbonia fabulina, Jones and Kirkby. Plate XII. Figs 9a-e. 



Gytherella injlata, Dawson, Acadian Geology, 1868, p. 206, fig. 485. 

 Carbonia fabulina, J. and K., 1879, Ann. Mag. N. H. ser. 5, vol. iv. p. 31, pi. 2, 

 figs. 1 — 9 ; and var. humilis, loc. cit. figs. 11 — 14. 



Perhaps the most interesting specimens from the Joggins Coal- 

 measures are a series of Carbonia fabulina and varieties, occurring 

 in a softish black shale which surrounds the base of the well-known 

 reptiliferous tree-stumps that were discovered by Dr. Dawson and 



