348 GEOLOGY AND PETROLOGY OF TKB GREAT SEUPEXTINE BELT OF N.S.W., 



Spirifera duplicicostata (Phillips). (Plate xxiii., fig. 4.) 

 Phillips, Illiis. Geol. Yorks., ii., 183ti, p. 218, t. 10, f. 1; Davidson, Brit. Carb. 



Brach., pp. 24, 22l! t. 3, f. 7-10; t. 4. f. 3, 5-11, 15-10?; t. 5, f. 3.5, 37; 



t. 52, f. 6. 

 The pedicle valve is very similar to Davidson's t. 4, f. 15-l(i. though it is too 

 imperfect to permit tlie observation of the marked inflection of the margin'il 

 regfiou. There is, however, a broad sulcus with about thirteen fine ribs therein, 

 and about thirty-five striatious on either side. While originally considering- the 

 forms illustrated in tliese figures as S. humerosa, Davidson later (\). 221) states 

 that he is inclined to refer these forms to S. duplicicostata- This course is there- 

 fore followed here The specimen is No. F.1652 of the Geological Survey col- 

 lection, and was obtained near the "Whale's Egg," five miles south-east of .Somer- 

 ton by Mr. Pittman. This form occurs in the zone of Di in England. 



Spirifera cf. jiosquen.sis (Fischer). (Plate xx., figs. 4, 5, U.) 

 Choristites musquensis, Fischer de Waldheim, Programme sur les Chonstite. p. S, 



No. 1, 1837. and Oryctogr. du gouv. de Moscow, 1831, p. 140, t. xxii., t. 



3; t. xxiv., f. 1-4; Spirifera mosqueii!<is, De V'ernueil and Keyserling, 



Russie et Oural, Vol. II.. p. 161, t. v., f. 2; Davidson, Brit. Carb. Hracli., 



p. 22-3, t. iv., f. 13, 14; t. xiii., f. Iti.* 

 Tliis form differs from ,S'. striata in the greater length of the shell, in nur 

 form there are about sixty ribs, which are very much broader on the siuus than 

 towards the ears, about ten ribs occurring on the sinus and mesial fold. Tlicre 

 is very little sign of concentric ornamentation. The length of hinge line is rather 

 less than the greatest width of the shell, and the area on the pedicle valve has 

 almost parallel sides and is about 3 mm. wide, and marked with faint vertical 

 .^triation. 



Dimensions: Breadth, 37 nun. (leng'th of hinge 33 mm.); length of pedii-le 

 valve, 35 mm. ; thickness of shell. 23 mm. 



Our specimen was obtained by Mrs. Scott from the shelly ridge in the iS.E. 

 of Babbinboon, and is in the collection of the University of Sydney. Other speci- 

 mens from Carroll Gap have been received by the Australian Museum from ]\Ir. 

 D. A. Porter; and these forms approach more closely to Davidson's illustration 

 of S. mosquensis tlian does oui' specimen in the more marked chiirHcfer of the 

 median fold. 



According to Freeh (32) this species is a characteristic fossil of the lower 

 portion of the Upper Carboniferous. A variety of it occurs in the zone D2 in 

 England. 



Spirifera pinguis (Sowerbyk (Plate xxi., figs. 9, 10.) 

 Sowerby, Min. Conch., iii., 1820, p. 125, t. 271; Davidson; Brit. Carb. Bracli., p. 



50. t. 10, f 1-12; .S. pinguis var. rotundatiis^ L. G. de Koninck, Foss. 



Pal. N. Galles Sud., 1877, English Translation 1898. p. 185, t. 14. f. 2, 2a; 



S. pinguis, Dun, Rec. Geol. Surv. N.S.W.. vii., 1902, ]). 84, t. xxii., f. 1, 



2, 5. 

 The specimens obtained from Mrs. Scott are typical exani|des of llic species. 

 The larger has a* length of 43 mm. and a breadth of 40 mm., there being eight 



• Diiviilson states: — "Prof. L. G. de Koninck assures me that the true Russian 

 Spirifera uioaquensis has not been found in (treat Britain, and that what lias been re. 

 ferred to it are merely variations in shape of Spirifera striata, and I feel incHned to 

 adopt the Professor's view." Brit. Carb. Brach., Suppl., 1880, p.;U5. 



