110 Mr. H. Seeley on Cambridge Geology. 



will be found constant. In the lower bed are some shell-less 

 Annelides. 



It ought to have been previously mentioned, that at Over*, a 

 few miles east of St. Ives, and west of the Kimmeridge Clay, the 

 Belemnites excentricus and some other fossils have been met with, 

 identical with those of Bluntisham ; and therefore it might be ex- 

 pected that the Elsworth rock should crop out near Holi well, which 

 is an intermediate point between Over and St. Ives. Now, in the 

 collection of Mr. James Carter of Cambridge is a series of fossils, 

 collected for him twenty years since, which he believes came 

 from Holiwell. The series contains Ammonites Herici and many 

 Elsworth fossils, as also some few new forms and several which 

 Elsworth has not produced and probably does not contain, such 

 as Dysaster bicordatus and Holectypus hemisphcericus, these two 

 species being very abundant. The lithological character of the bed 

 is quite the same as that of the Elsworth rock. I do not insist 

 upon a necessary identity ; for the locality is not given with that 

 certainty which such an assumption ought to require ; and the pits 

 being now abandoned and filled in, verification will be impos- 

 sible. The fact must go for what it is worth, and, judging from 

 circumstances in the country to the north-east, where there are 

 other outcrops of rock, it will not be worthless. It may indicate 

 an interesting synclinal between St. Ives and Over, which is 

 probably a consequence of a vast downthrow fault known to 

 exist far to the east. 



A 8 A y A /3 



a, Boxworth rock ; /3, Elsworth rock ; y, ?St. Ives rock ; S, St. Neot's rock ; A, Oxford Clay. 

 S. N. 



/S A y A y 



T, Tetworth Clay ; G, Shanklin Sands ; B, Boulder Clay ; F, Flint gravel. 



Thus it has been endeavoured to illustrate a succession which 

 will hereafter be elaborated at more appropriate length. 

 * Pronounced Uv'er. 



