Tol. 67.] KUXOZOIC UOLLUSCA FROM CTBENAICA. 025 



Cardium ttjbeectjlatttm Linnaeus. 



Cardium tuberculatum Linnaeus, ' Systema Naturae ' 17^8, ed. 10, p. 679 ; Sacco, 

 ' Moll. Terr. Terz. Piemonte' 1899, pt, 27, pi. ix, figs. 16-17 & p. 40 ; Bede, 

 Feuille des Jeunes Naturalistes, 1901, No. 408, p. 5. 



Remarks. — Two fragmentary left valves represent this species, 

 showing twenty costae with somewhat eroded summits, yet pre- 

 serving in places close and equidistant ambulations or nodosities 

 which are more delicate on the face of the shell but larger and 

 swollen on the anterior surface. Close, squamulose, transverse 

 striations decorate the remote intercostal grooves. The posterior 

 side is deep and obliquely truncated. 



Dimensions (approximate: largest left valve). — Length = 

 55 millimetres ; height = 65 mm.; diameter=30 mm. 



The species is a well-known Mediterranean form. It also occurs 

 in the Pliocene rocks of Italy, as described by Prof. Sacco and a 

 number of previous authors, and M. Paul Bede records it from the 

 ancient Quaternary deposits of Tunisia (Sfax). This species would 

 include Cardium rusticum of Linnaeus, a fact acknowledged by most 

 conchologists. 



Occurrence. — The matrix associated with these specimens is 

 a hard siliceous limestone, containing in abundance minute pebbly 

 fragments of a white material ; otherwise, the rock is brick-red 

 in colour. 



Locality. — West of Ptolemeta. 



III. Helvetiax-Toetoniax. 



The Helvetiau-Tortonian (=Yindobonian of Depe'ret) rocks are 

 particularly well known in various regions of Northern Africa, 

 having been described by Zittel, Fuchs, the officers of the Geo- 

 logical Survey of Egypt, Dr. JBlanckenhorn, and many other 

 authorities for Egypt, including Dr. Pachundaki, the last-named in 

 connexion with the structure of the Marmarican plateau to the 

 west of Alexandria. The same beds are widely distributed over 

 Mediterranean countries ; and the few fossils from Cyrenaica now 

 described are fairly well represented in the European development 

 of this part of the Miocene System. Accompanying the shell- 

 remains from Gubah are some fragmentary Balanus with probable 

 affinities to B. concavus of Bronn, a related form of this species 

 having been recognized bv Fuchs in the Helvetian deposits of 

 GenefTe (Egypt). 



The other localities recognized as yielding fossils of this age in 

 Cyrenaica are the Grotto, Lethe ' River,' near Benghazi ; the plain 

 east of Benghazi (which yields a limestone full of Lithothanvnion 

 and Amphistegina, etc.) ; and the tract extending from Merj Plain 

 to AVadi Hamema. 



