80 FORAMINIFERA OF THE CRAG. 



so rich in MoUusca, from Walton-on-the-Naze, has not resulted in any additions 

 to the recorded species. 



OLDER PLIOCENE [LOWER CRAG]. 

 ST. ERTH BEDS. — At St. Erth, near Marazion, Cornwall, a very small outlier 

 of sands and clays occurs, the Pliocene age of which was definitely established by 

 the late Mr. S. V. "Wood, jun. ; ' and later a full description of the exposure was 

 given by Messrs. P. F, Kendall and R. G. Bell,^ from which the following section is 

 taken [with the dimensions added from Mr. C. Reid's ' Memoir,' p. 60] : 



Vegetable soil. 



3 ft. to 7 ft Bed L " Head," an argillaceous deposit with angular frag- 

 ments of Killas and other rocks ; probably of 

 glacial origin. 



2. Fine yellow sand. 



3. Yellow clay, without fossils ; separated from Bed 2 



by a thin layer of coarse sand (" Growder "). 

 1 ft. 6 in. to 3 ft.... 4. Blue clay, with many fossils. 



5. Layer of scattered quartzose pebbles. 



6. Fine quartzose sand, yellow above and purplish 



below. 



7. Very coarse, highly ferruginous sand (" Growder"). 



The thickness of the several beds is very variable, and the total depth of the pit 

 12 feet to 14 feet. No. 4 is the fossiliferous bed, in which nearly all the organic 

 remains were found. 



The Foi'aminifera have been most carefully worked out by our friend Mr. 

 Fortescue W. Millett, and the lists published by him * give a total of 1(33 species and 

 well-marked varieties. Of this number seventy-six are also met with in the 

 Coralline Crag, the additions now made to the rhizopodal fauna of the latter 

 emphasising the similarity to a considerable degree. 



Mr. Millett says in his " Additional Notes," " Every day the difficulty of ascer- 

 taining the age of any particular bed by the Foraminifera it contains becomes 

 more evident; for rarely does it happen that an investigation is made of any 

 deposit, recent or fossil, which does not extend our knowledge of the existence of 



1 " On a New Deposit of Pliocene Age at St. Erth, near the Land's End, Cornwall," ' Quart. 

 Journ. Geol. Soc.,' vol. xli, 1885, pp. 65 — 73. 



- " On the Pliocene Beds of St. Erth," ' Quart. Journ. G-eol. Soc.,' 1886, pp. 201—215. 



3 F. W. Millett, "Notes on the Fossil Foraminifera of the St. Erth Clay Pits," 'Trans. Roy. 

 Geol. Soc. Cornwall,' vol. x, pt. 7, 1885, pp. 213— 216 ; " Additional Notes on the Foraminifera of the 

 St. Erth Clay," op. cit., vol. x, 1886, pp. 222—226; "The Foraminifera of the Pliocene Beds of 

 St. Erth," op. cit., vol. xi, 1894, pp. 655—661. 



