452 [June 26, 



considered them to be allied to Trigonellites or Aptychus. He 

 divides tlie Aptyclii into three groups, A. cornei, imbricati, and 

 cellulosi, the former of which differs from the two latter (which 

 are calcareous and bivalve,) in being corneous and univalve, both 

 which characters are applicable to the fossils which I have above 

 described. He supposes that in the corneous species a certain 

 degree of motion was effected in the two halves of the body by 

 means of its own elasticity, while in the calcareous groups the 

 same end was obtained by means of a bivalve structure. He 

 enumerates five species of the corneous group, all of which are 

 from the lias and inferior oolite, and which, like the imbricate 

 and cellulous species, are occasionally found in the interior of 

 Ammonites, occupying a symmetrical position, and corresponding 

 in their dimensions to the shell in which they are found. From 

 these and other reasons, M. Voltz regards the whole of this group 

 of fossils as appendages to the animals of Ammonites, a view 

 which is confirmed by the facts adduced in the present commu- 

 nication. 



5. Notice concerning the Tertiary Deposits in the south of Spain. 

 By James Smith, Esq., of Jordanhill, F.G-.S. 



In the bay of Gibraltar, immediately to the north of the plain 

 which separates the fortress from the Spanish territory, we meet 

 with a series of low swelling hills of yellow rubbly sandstone, the 

 beds dipping to the S.W. at an angle of 12°, and abounding in 

 marine tertiary fossils. Of these fossils, there is only a small 

 variety, and of many of the species I could only find casts ; but these 

 were sufficient to furnish an important link, connecting distant 

 deposits ; for upon comparing them with the specimens in the 

 Society's Museum, illustrative of Col. Silvertop's account of the 

 tertiary formation of Murcia and Grenada, and Lieut. Spratt's 

 paper on the Geology of Malta, I find that the three deposits are 

 identical. 



I have also observed tertiary beds at Cadiz, and between Xeres 

 and Seville, which, I am satisfied, belong to the same deposit ; 

 and Mr. Sharpe, in his paper on the Geology of Lisbon, has as- 

 signed reasons, with which I entirely agree, for considering that 

 the tertiary beds of the Tagus coincide with those of the south 

 of Spain.* 



In a communication respecting the age of the Lisbon tertiary 

 beds, I stated the grounds which led me to conclude that it was 

 nearly the same as that of the Bourdeaux deposit, and I may now 

 add, that I consider it more ancient than the Touraine Faluns, 

 or older crag, f It will be seen, from the report of Professor 



* Geol. Transactions, 2d series, vol. vi. p. 113. 

 f Geol. Proceedings, vol. iii. p. 492. 



