338 J. F. BLAKE AND W. H. HUDLESTON ON 



fine suboolitic limestones undergoes considerable modification, as, 

 indeed, do all the groups if traced for any distance. 



/, average 20 feet. — These beds form the backbone of the " Co- 

 ralline Oolite " of Pickering, where, in one of the quarries on the 

 west side, they have a thickness of 22 feet. Chemnitzia heddingto- 

 nensis and Nerincea are tolerably abundant throughout, but especially 

 so in a block towards the top of the series, which is evidently an old 

 shell-bed. The sparry sections of Chemnitzia, in the white lime- 

 stone or oolite, produce an appearance known to the workmen as 

 " rabbit-eye;" and these beds mark the termination for a while of the 

 more fossiliferous limestones. This series at Pickering may be viewed 

 on the whole as a mixture of creamy limestones full of oolitic grains 

 with true oolites. On account of the great difficulty in extracting 

 the fossils, the fauna cannot be determined with the same ease as 

 that of the Trigonia-be&s. There are multitudes of shells in layers, 

 but in such a compact matrix as to defy extraction. Astarte ovata 

 and Lucina aliena are amongst the most plentiful of the bivalves ; 

 and Trigonice very like T. perlata occur sparingly. 



e, 10 feet. — The " black posts " are dirty-looking limestones of 

 somewhat variable thickness and not in the least oolitic, but rather 

 carbonaceous. Portions are quite slaty and of no use to the lime- 

 burners. The lower parts are of better quality : here the bedding is 

 so uneven that the workmen call one of the bottom blocks " hilly 

 and holey." It is from just below this that the Ammonite which 

 most resembles A. varicostatus is said to come ; but there are no sections 

 of fossils on the surface of the stone, and the contrast afforded by 

 this group to the fossiliferous and sparkling limestones below is most 

 complete. This subdivision, of which there is not a trace in any part 

 of the Scarborough district, has great importance in the Pickering 

 district. It certainly prefigures the " throstler ;" for in the neigh- 

 bourhood of Kirkby Moorside there are indications that " black 

 posts," rag, and " throstler " all more or less replace each other 

 or commingle. The base of the subdivision " hilly and holey," is 

 the cave-line throughout the district, as we shall see at Kirkdale 

 (page 34G). 



cZ, 5 feet. — In the first quarry on the west side the top course 

 of limestone, resting on 8 feet of the earthy limestone (e), has a thick- 

 ness of 5 feet 6 inches, and contains layers of stone having a false 

 dip of nearly 15° in a westerly direction ; yet the upper surface is 

 quite level, as though it had been planed away subsequently. Here 

 the rock is full of vertical fissures filled with clay and other matters 

 from above. In the second quarry on the west side these beds have 

 a thickness of eight feet, but the false-bedding is inclined at a lower 

 angle. It is rather remarkable that the slaty limestones (e) shrink 

 correspondingly to the increase of these beds. At the principal 

 quarry on the east side the face, exposed during the summer of 1875, 

 exhibited only 2 feet 6 inches belonging to this group. It is there 

 called the " iron post," and is a hard, blue-speckled, compact lime- 

 stone, full of small, whitish, nodular bodies. Generally speaking, it 



