If? 8 Geological Society. 



of the inferior oolite on the Yorkshire coast is Blue Wick ; and the 

 following is the succession of the strata which it presents in ascend- 

 ing order : 



Feet. 



1 . Thick beds of dark grey finely grained sandstone . . 20 



2. Irregular beds of yellow sandstone '20 



3. Hard ironshot sandstone containing small pebbles. . I J 



4. Irregular beds of yellow sandstone, in some parts 



ironshot, and inclosing layers of pebbles 30 



5. Hard ironstone, many fossils 4 



6. Hard ironstone, no fossils 8 



The beds No. 1. contain, in their lower part, argillaceous nodules 

 resembling those of the Alum shale, and inclose great numbers of 

 Ammonites striatuluSj Lingula Beanii, Orbicula reflexa, and, in less 

 abundance, an Avicula, resembling^. ccAiwo^a, and Terebratula bidens^ 

 Above this nodular bed no fossils have been noticed till within 1 feet 

 of the top of No. 1, where anotlier layer of similar concretions occurs, 

 inclosing portions of an Astacus resembling in some respects Astacus 

 rosiratus, and a species agreeing with one found in the Cornbrash. 

 A little nearer the top of No. 1. is a thin seam containing great 

 numbers of Vermetus compressus, which is found also in the coralline 

 oolite of Yorkshire. 



The division No. 2. presents throughout its whole thickness small 

 fragments of dicotyledonous wood with an undescribed Belemnite j 

 and towards the top are found, though rarely, Mya litterula, and still 

 higher two species of Ammonites apparently new. 



The bed No. 3. contains the same Belemnite as No. 2, but is 

 characterized by great abundance of Terebratula iriUneata, 



No. 4. is destitute of fossils, except near its junction with the over- 

 lying bed, where it contains the Belemnite and Avicula of Nos. 1. 

 and 2. 



The bed No. 5, though not more than 2 feet thick, incloses the 

 greater part of the fossils of the inferior oolite of the Yorkshire coast, 

 and the following is a list of the species given by Mr. Williamson, as 

 occurring chiefly in the middle and lower portions of the bed : 



Trochus graniclatus, T, bisertus, T. pyramidalis. Solarium calix, Nerita 

 costata. Turbo Icsvigatus, T. funiciilatus, Rostellaria compositUy Natica ad- 

 ductay N. tumiduluy Terebi^a vetusta, Acteon humeralis, Auricula Sedgviciy 

 Ostrea Marshiiy O. solitaria, Pecten virguliferus, P. abjectus, Trigonia angu- 

 latOy T. costata, T. striata, T. gibbosa, Avicula Braambui-iensis, Astarti' ete- 

 gans, A. minima^ Modiola pulchra, M. cuneatay Mytilus sublcevisy Cardifa 

 similis, Nucula axiniformisy Isocardia concentricay Cardium incertum, Phola- 

 domya ovalis, Unio abductuSy Gastrochcsna tortuosa. 



The upper part of the stratum is characterized by Turrilella muri- 

 cata, T. quadrivittata, T. humifusa, T. cingenda (Phillips) in great 

 abundance, Melania HeddingtonensiSy Terebratula obsoleta, and Ca- 

 ryophyllia convexa. 



In No. 6, the highest stratum of the inferior oolite^ no fossils have 

 been noticed by Mr. Williamson. 



2. Immediately above the inferior oolite lies the lower sandstoneand 



