368 J- F. BLAKE AND W. H. HtTDLESTON ON" 



It is certainly a matter for regret that greater precision cannot be 

 given in the way of localizing the above list; for if that were pos- 

 sible a great step in advance towards a proper classification of the 

 Malton oolites might be made. Still it is certain that, although by 

 no means exhaustive, the list does not contain any species which 

 may not be found between the top of the passage-beds and the base 

 of the Coral Rag, excluding both these subformations. The list is 

 no doubt highly characteristic of an oolitic facies in the widest ac- 

 ceptation of that term. A comparison with the Coral Rag list of 

 Langton-Grimston, subsequently given, will be found instructive. 



The general character of the Coralline oolite of the Howardian 

 district must be gathered from the above description of the Malton 

 quarries. There are most extensive quarries in this class of rock 

 between Malton and Appleton : they are not very obviously fossili- 

 ferous ; but doubtless such fossils as they have from time to time 

 yielded have gone to swell the Malton list. As we get further west- 

 ward in this direction, beyond Appleton for instance, the Coralline 

 oolite does not make such a display in the quarries, their upper 

 portions being occupied by Coral Rag, and sometimes by an inter- 

 mediate class of beds, already alluded to under the name of Coral 

 shell-beds, where the branches of the Thecosmilia and the delicate 

 fingers of Rhabdophi/llia are mixed up in an oolite or limestone con- 

 taining shells belonging to both facies. The presence of corals, and 

 of spines of Cidaris florigemma induces us to include this group 

 with the Rag of this district, presently to be described. Through- 

 out the western portion of our Howardian district the Coralline 

 oolite occupies a place far inferior in interest to the more fossiliferous 

 Coral Rag, there so richly developed. It consists for the most part 

 of thick beds of oolite of a most monotonous appearance, rarely re- 

 lieved by a Nerincea or a Chemnitzia. These beds of soft stone, 

 however, are much quarried for lime ; they have a thickness, where 

 all seen, of from 25 to 30 feet. We have already alluded to a quarry 

 in Hovingham village, where, at one end, about 25 feet of the most 

 unfossiliferous oolite in Yorkshire may be seen. At the other end 

 of the quarry a portion of this is faulted against the Coral Rag, and 

 an excellent opportunity for observing the contrast between the two 

 classes of rock is obtained. 



Coral Rag. — The class of beds which overlie the Coralline oolite 

 of Malton, and of the region to the westward, presents us in this 

 area with considerable variety, being sometimes a mineralized coral 

 reef, hard and impenetrable (as is the case with the lower beds of b, 

 fig. 19), sometimes a dense creamy limestone with few but large 

 oolitic granules, and sometimes, as at Hildenley, an almost homo- 

 geneous limestone, resembling hardened chalk. 



In the district east of the Derwent, where there are some notable 

 examples of the reef-like character just alluded to, we have also another 

 phase of the Rag, of which the jSTorth-Grimston limestone may be ac- 

 cepted as the type. There, reposing upon crumbling pisolites with a 

 decidedly Upper Corallian or Rag fauna, are thick beds of indurated 

 calcareous mud, enclosing semi-crystallized masses of coral of various 



