348 l*rof. Sedgwick on the Clamjication of the Strata [May, 



Any person who had frequent opportunities of access to this 

 part of the coast might select a fine suite of organic remains 

 illustrating the natural history of the formation. The series 

 which fell under my own notice must, of course, be very imper- 

 fect ; and I only give it in this place in the hope of conveying 

 some notion of the manner in which the fossils are grouped in 

 the several parts of the section just described. 



The fossils of the five lowest groups (No. 1 to No, 5) were as 

 follows:* — 1. /Ammonites. 2. Natititites. Both these were 

 rare, and generally in the form of fragments. 3. Belemnites 



. 4. Gtyph&a dilatata, confined to the lowest group 



No. 1. 5. Ostrea, (a) a large flat species, {b) a small convex 

 species, (c) ostrea Marshii . 6. Trigoiiia cluveUata. 7. Pec- 

 ten, two or three species ; one small species with undulating 

 striae is very abundant. 8. Pinna lanceotata. (?) 9. Many casts 

 of a shell resembling a mya are found in all parts of the form- 

 ation. 



The fossils of the central portion of the formation including 

 Nos. 6, 7, 8, of the general section were as follows: 



1. Ostrea, (a) small convex species ; (/y) deltoidea, found in the 

 group No. 8. 2. Pecten, the small species abovementioned. 

 3. Perna aviculoides. 4, Many casts of a mya (?). 5. Many 



fragments of various bivalves . 6. Melania, (a) HeadingtO' 



niensis, (b) striata, associated with various casts of univalves. 

 7. Echinus, clypeus clunicularis. 



Some species of fossils of the group No. 9 are in infinite 

 abundance. Whole beds are entirely made up of crystalline 

 fragments of the trigonia clavellata and other characteristic 

 shells. This association of petrified shells and corals with inco- 

 herent ferruginous marly beds gives rise to a variety of rubbly 

 limestone, provincially called coral-rag, a term now generally 

 adopted by English geologists. The series exhibited in this 

 group is as follows: — 1. Ostrea, {a) gregaria, (/») sofitaria, 

 (c) Marshii, ? id) deltoidea. 2. Trigonia, («) clavellata, 

 {!)) elongata (?), (c) costala. 3. Pecten, the small species with 

 .undulating stria;. 4. Pinna, («) lanceolata, {b) granulata. 



5. Perna, {a) aviculoides, {b) a flat species of a trapezoidal form. 



6. Terebratula incvnsfans. 7. Melania, (a) Headingtoniemis, 

 {!)) striata. 8. Turbo muricalus. 9. Trochus reticulatus. 

 10. Turritellamuricata. 11. jEt7/j/»/s (o) spines and fragments 



oi cidaris papillata, (b) clypeus clunicularis . 12. A few 



fragments of the ramose madrepore (caryophyllia), and other 

 coralline bodies resembling those which abound in the well- 

 known quarries of Steeple Ashton, &c. &c. Of the preceding 

 list, No. 1 {Ostrea deltoidea), No. 3, No. 4 {Pinna granulata), 



* The names of the several species of testacta are adopted from Sowerby's 3Iineral 

 Conchologj', except where the contrary is expressed. 



