Thomas Sheppard — CnjptocMdm in KeUamiijs Rock. 537 



particular specimens. The geology of Mill Hill is simple, and may 

 be briefly stated as follows : — 



Formations. 



1. Superficial Gravels. 



2. Kellaways Rock. 



3. Kellaways Sand. 



4 . Great Oolite Clay or 



Saudy Oolite. 



5. Millepore Oolite. 



DESCKirxiox. 



"Where Exposed. 



Loose waterworu gravel and In a ([iiarry ou tlie top of the 



sand. I hill. 



Hard sandstone with fossils ( i In the quarry where the 

 Ferruginous sands. ) Saurian bones occurred 



Sand and clay. 



Hard limestone with fossils. 



In a well-section lower down 



the hill. 

 At the base of the hill. 



The fact that thin beds of sandstone, with well-known Kellaways 

 Rock fossils, occur some six feet above the bed containing the 

 remains, clearly indicates that the bones were found in what is 

 known as the Kellaways Sands. These beds are well exposed in 

 the railway cutting at South Cave, a short distance away, thongh of 

 this section Mr. Fox-Strangways says,' " the beds [of the Great 

 Oolite Clay] are so similar to the sands of the Kellaways Kock 

 above that it is difficult to fix an exact horizon between them." 



The question arises, does the lower part of the section on Mill 

 Hill, in which the Gryptodeidus remains were found, belong to the 

 Kellaways Sands or the Great Oolite Clay series ? The beds of the 

 Great Oolite Clay (sometimes called the 'Sandy Oolite') consist 

 mostly of sands, clayey in parts.- This rock, however, occurs 

 further down the hill. In a previous paper ^ I have described a well 

 section that was being made in 1895, which was sunk in the Great 

 •Oolite Clay. It showed six feet of stiff blue clay, greatly mottled 

 and stained with yellow, containing no fossils or stones. Below 

 this was about three feet of yellow clay ; the standing water pre- 

 vented me from seeing further, but at one end of the heap of 

 excavated material at the top of the well was a quantity of fine 

 yellow sand, which had no doubt been taken from below the yellow 

 clay. This section was some distance down the hill. 



At the bottom of Mill Hill are some small exposures in the 

 iMillepore Oolite, whilst at the top I have frequently observed slabs 

 of Kellaways Rock in the floor of the gravel-pit, hard masses of 

 this rock evidently occurring in a few places towards the top of 

 the hill. Taking all into consideration, therefore, there can be little 

 doubt that the Saurian occurred in the Kellaways Sand, and the 

 discovery of these relics of Crijptocleidiis give that animal a much 

 earlier and longer period of sojourn upon this earth than previous 

 •records, from the Oxford Clay, have warranted. 



In searching for records of similar finds previously obtained from 



> "The Geology of the Country between York and Hull" : Geol. Survey Mem., 

 1886, p. 22. 



2 Loc. cit., p. 22. 



^ " Notes on Ekphct:^ antlqiim and other remains from the Gravels at Elloughton, 

 near Brough, East Yorkshire" : Proc. Yorks. Geol. and Polyt. Soc, 1897, p.^222. 



