278 



A. J. JTTKE8-BR0WNE ON THE RELATIONS OF 



List (continued). 



Name. 



Lower 

 G-ault. 



Upper 

 Gault. 



Gault 

 superieur. 



Upper 



Green- 

 sand &c. 



Brought forward 



17 



it 

 it 



it 

 it 

 it 

 it 

 it 

 it 

 It 



it 



it 

 * 

 it 



* 

 it 

 it 

 it 



it 



11 



it 



it 

 * 



it 



it 

 a 



it? 



20 



it 



* 



it 



it 

 it 



it 



it 

 it 



7 



* 

 it 



* 



it 

 it 













Hugardiana, If Orb 



Nucula albensis, If Orb 



Vibrayeana, If Orb 



Leda solea, If Orb 







Lucina tenera, Sow 



Cardita tenuicosta, Sow 



Tellina phaseolina, If Orb 



Pholadomya decussata, Sow., var. . 

 Rhynchonella compressa, Lam. . . . 













Hemioon Cunningtoni, Bell 



Necrocarcinus Woodwardi, Bell . . . 







Homolopsis Edwardsii, Bell 





Cidaris gaultina, Forbes 



Heixtiaster asterias ?, Forbes 



Ventriculites mammillaris, Smith. 

 Cephalites compressus, T. Smith. 

 guttatus, T. Smith 



capitatus, T. Smith. 



Brachiolites tubulatus, T. Smith. 



Total 62 



35 



20 



30 



15 



An inspection of the latter of these two lists shows that by far 

 the larger number of the rare fossils belong either to the fauna of 

 the Lower Gault or to the Vraconnien. That the latter fauna 

 should be so largely represented in the above list is to be accounted 

 for by the fact that it also contains a number of lingerers from the 

 lower beds (' Faune de Cheville/ p. 198*), while 12 out of the 30 are 

 species peculiar to the continental Gault superieur ; and being un- 

 known elsewhere in England, it is not surprising that they should 

 be rare at Cambridge. 



The number of Lower Gault forms (35) is more significant, and 

 seems to show that the denudation near Cambridge had reached the 

 beds of that formation ; while their rarity indicates either how small 

 a portion of those strata had suffered erosion, or, what I think more 

 probable, how unfossiliferous it has been. 



■* Renevier, "Faune de Cheyille," Soc. Vaudoise des So. Nat. tome ix. p. 389. 



