PRESTWICH BRITISH AND FOREIGN TERTIARIES. 89 



both on the outside of the masses and within. In a few instances 

 the shelly matter is preserved. Flattened spatangoid urchins are 

 the most abundant of the fossils. 



[See Proceedings Phil. Soc. Glasgow, 1849, vol. iii. No. 1. p. 33, &c. ; and 

 Phil. Mag. 1850, vol. xxxvii. p. 430, &c.] 



EXPLANATION OF PLATE IL 



[Figs. 1-3 are from the Chalk-flints, and figs. 4-9 from the Upper Greensand, of 



Aberdeenshire.] 



Fig. 1 a. Semiescharipora mumia, If Orb. 1 h. Portion of the lower surface mag- 

 nified ; — some of the cells are broken away on the right, and show 

 impressions of the ornamented upper surfaces. 



2 a. Flustrellaria dentata, B^Orb. 2 b. Portion of the under surface magni- 



fied. 



3 a. Lima elegans, Nilsson. 3 b. Portion of exterior magnified. 



4 a. Toxaster, sp. ; internal cast. 4 b. Side view of the same. 4 c. Portion 



magnified. 



5 a. Avicula simulata, Baily ; cast of the interior. 5 b. Portion of the same 



magnified. 



6 a. Limopsis texturata, Salter ; cast of the interior. 6 b. Portions of the 



exterior magnified. 

 7. Cyprina Fergusoni, Sailer ; cast of the exterior. (Some perfect internal 

 casts have been omitted by accident from the plate.) 



8 a. Dentalium coelatulum, Baily. 8 b. Portion of the exterior magnified. 



9 a. Ammonites, sp., fragment. 9 b. Edge-view of the same. 



10. Ammonites, sp. The upper portion is only an impression of the outside 

 in the matrix. 



On the Correlation of the Eocene Tertiaries q/* England, 

 France, and Belgium. By J. Prestwich, Esq., F.R.S., 

 F.G.S. 



[Read June 18, 1856*.] 



Contents. 

 Part XL — The Paris Group (continued). 



§ 1. The Bracklesham Sands and Calcaire grossier, — general features, and 



shells common to the two deposits. 

 § 2. The Calcaire grossier, — its divisions, and their organic remains compared 



with those of Bracklesham. The relative conditions under which 



these deposits were formed. 

 § 3. The Belgian equivalent of the Calcaire grossier and Bracklesham Sands, 



— the Bruxellian System. 

 § 4. The Barton Clay, Sables moyens or Gres de Beauchamp, and Laekenian 



System. Fossils of the Barton Clay. 

 § 5. Concluding Remarks — physical conditions prevailing during this part 



of the Paris Tertiary period. 



* For the other communications read at this Evening's Meeting, see Quart. 

 Journ. Geol. Soc. vol. xii. p. 384, &c. 



