from the '^ Cambridge Greensandy 49 



material from Swaffham^ Cambridgeshire, kindly supplied 

 me, as in the former instance, by Mr. H. Woods, of Cam- 

 bridge. 



From tliis present account we are enabled to judge some- 

 what of tlie richness of the foraminiferal fauna of this 

 deposit, since it brings the total number of forms found to 

 about 140. 



Our previous knowledge of this group of fossils from the 

 Cambridge Greensand has been derived chiefly from the list 

 given by G. E.. Vine *, who enumerates 31 forms from the 

 " Greensand and Chalk-marl of Cambridge (Pliosphate beds)." 

 Some of tlie names there given have since been referred to 

 other genera, owing to further studies of the Cretaceous 

 Foraminifera ; but the species will be noticed in this present 

 paper, in the majority of cases, under their several specific 

 names. 



The Foraminifera of the Cambridge Greensand show in 

 many cases, especially amongst the larger species, as Gristel- 

 laria gaultina, Vaginulina truncata, a marked abrasion of 

 their tests. These specimens have therefore either been 

 derived from an older deposit, or they have been subjected to 

 the action of currents for a considerable time before they were 

 covered by the 'deposit in which they are now found. I am, 

 however, strongly inclined to believe that a large proportion 

 of the microzoic fauna has been derived from the upper beds 

 of the Gault. Other forms there are in the Cambridge Green- 

 sand, minute and well-preserved; these may or may not 

 represent a fauna contemporaneous with the formation of the 

 bed. It is quite possible that even the perfect and minute 

 forms were in some cases floated off and transferred to the 

 later deposit. The facies from this bed is remarkably like 

 that of the Greensand seam in the Gault — zone xii. — at 

 Folkestone. 



In the following account of the Foraminifera synonymy is 

 avoided as far as possible for the sake of brevity ; and since 

 more copious references will, in the majority of cases, be found 

 in my papers on Gault Foraminifera from Folkestone f, the 

 secondary references given here will mainly be from those 

 pages. Only in cases where necessary, as in the non-occur- 

 rence of the species at Folkestone, is a fuller synonymy 

 sometimes given. 



• Proc. Yorkshire Geol. and Poljtech. Soc. 1889, vol. xi. pp. 273, 274. 

 t See Journ. R. Micr. Soc, October 1891-February 1898 (10 parts). 



Ann. & Mag. K Hist. Ser. 7. Vol. iii. 4 



