Mollusca front tlic Bol-keveld Beds. 267 



Actinopteria eschicegoi , Clarke," from the same formation in Brazil, 

 IS an allied form. 



Localiti/. — (No. 81) Koudevekl Berg, highest part of main road 

 under 1st Sandstone. 



ACTINOPTERIA sp. 



There is an external cast of a portion of a large shell (No. 83) 

 referable to the genus Actinopteria but in a very imperfect state of 

 preservation. The body is oblique with an acute beak ; the posterior 

 wing is large and flattened ; the anterior ear is long and narrow ; the 

 ornamentation consists of rather coarse radiating ribs crossed 

 towards the margins by concentric ridges of subequal strength. 

 There appears to be a general resemblance to Actinopteria subde- 

 cussata, Hall, t but our specimen is too fragmentary and imperfectly 

 preserved for any precise comparison or description. 



The length of the valve is a little over 60 mm. 



Locality. — (No. 83) Gydo Pass, Ceres. 



MODIOMORPHA BAINI (Sharpe). 



1856. Modiolopsis '^ Bainii, Sharpe, Trans. Geol. Soc, ser. 2, 

 vol. vii., p. 213, pi. xxvii., fig. 9. 



■This species was described by Sharpe as follows : " Shell nearly 

 rhomboidal : beaks close to the anterior end : each valve divided into 

 two nearly equal portions by a rounded ridge which reaches from the 

 beak to the ventral-posterior margin : anterior end very short and 

 truncated ; posterior end broad and sloping aw^ay from the central 

 ridge. Length 1 inch ; breadth 2 inches ; thickness |-ths of an inch. 

 . . . The cast shows some traces of concentric lines of growth over 

 the whole valve and of several lines radiating backwards from the 

 beak over the anterior portion." In one of our specimens (No. Ill) 

 the above-mentioned umbonal ridge is well seen and has a faint 

 shallow depression parallel to it in front. 



DinienHions. — Length (No. Ill) 85 nnn., (No. 91) 45 mm. 

 Height ,, 22 mm., ,, 30 mm. 



Affinities. — This species may be compared with Modiotnorplia alta, 

 Conrad,! of the Hamilton Group. 



Localities. — (No. Ill) 1st Sandstone, near Klein Straat Siding. 

 .(No. 91) Gydo Pass, near top, Ceres ; Leo Hoek (Leeuwen Fontein) 

 (type). 



* Clarke, op. cit., p. 4o, pi. v.. figs. 1, 2, 4-6, 8-10; Katzer, ap. cit., p. 207. 

 t. xiv., tig. 1. 



t Hall, op. rii., p. 110, pi. xvii., figs. 23, 25-27, 29-31. 

 \ Hall, op. rit., p. 278, pi. xxxvii., figs. 1, 2, 7-12, 15, 16. 



