1826.] whicJt appear on the Yorkshire Coast. 347 



would in some measure approach to the configuration of these 

 singular beds. The stems very seldom exhibit any indications 

 of organic structure, but I think that some of them must have 

 originated in the presence of alcyonia, or of other genera of the 

 lower class of zoophytes. 



No, 2. Many thin beds of yellow sand and sandstone, very 

 much resembhng the sands of the inferior oolite. 



No. 3. Strong beds of calcareous grit in structure like No. 1, 

 but more ferruginous, and separated into prismatic vertical 

 masses by a double system of fissures. The three preceding 

 groups extend from the jetty to the first headland. 



No. 4. Blue argillaceous beds alternating with hard compact 

 beds which lose the character of sandstone, and have a nearly 

 even fracture. 



No. 5. Beds of yellow sand resembhng No. 2. Near the top 

 are beds of calcareous grit with argillaceous partings, in struc- 

 ture resembhng the beds of Nos. 1 and 3. 



No. 6. Many beds of pure oohte with argillaceous partings, 

 alternating witli other shelly oolitic beds, somewhat resembhng 

 forest-marble. In some of these beds, the oolitic particles were 

 associated with a variety of marl, and were not coherent. 



No. 7. Thin beds of oolitic marl containing innumerable spe- 

 cimens of a small echinus {Cli/peus clumcularis), casts of mela- 

 nice, &c. 



No. 8. A group of beds of impure sandy oolite. It contains, 

 along with various fossils of the preceding groups, a few speci- 

 mens of the ostrea deltoidea. 



No. 9. A large group, in the lowest portion of which are 

 masses of coral rag containing the ramose madrepore {caryo- 

 phyllia), and other fossils of Steeple Ashton, mixed with innu- 

 merable fragments of the trigonia clavellata. In the higher 

 portion of this group are many meagre sandy beds neai"ly 

 resembling the calcareous grit of some of the inferior groups of 

 this section; containing, however, more calcareous matter, and 

 a much finer suite of organic remains. 



No. 10. Kimmeridge clay, with large beds oi i\\e ostrea del- 

 toidea. 



No. 11. Beds of ferruginous impure calcareous grit, partially 

 oolitic, and alternating with beds of red and green-sand, and 

 blue clay containing the ostrea deltoidea.* 



No. 12. The remaining portion of the cliff on the way towards 

 Portland ferry is composed of Kimmeridge clay, containing the 

 most characteristic fossils of that formation. 



* This very remarkable group is seen in the part of the cliff immetliately under the 

 ruined castle. The whole thickness of the groups from No. 1 to No, 9 inclusive, must 

 be considerably greater than the thickness of the same formation near Oxford, whicli is 

 estimated by iilr. Cor.ybeare at something less than '<!00 feet (p. 185). In some places 

 in Yorkshire, the thickness of the calcareous grit, without the oolite, has been estimated 

 at 200 feet.— (" burvey of the Yorkshire Coast," p. 11.) 



