MOOEE ABNOEMAL SECONDAEY DEPOSITS. 465 



quarries near the railway- cutting in which the " White Lias " with 

 the succeeding deposits can be well studied. 



h. Organic Remains in Ehoetic White Lias. — The organic contents of 

 the " White Lias," considering the large area of its development, are 

 comparatively few generically, and, being usually in casts, are difficult 

 to determine specifically. It yields but two corals, a Montlivaltia, 

 and Thecosmilia MicheUni ? ; and it is worthy of remark that Pecten 

 Pollux (Suttonensis, Taw.), in a dwarf form, appears in it for the 

 first time, and in some localities is not uncommon. 



Montlivaltia, sp. Axinus concentricus. 



Thecosmilia Michelini ? elongatus. 



Cidaris Edwardsii. Cardium RliEeticum. 



Cythere liassica. Lucina ? 



Avicula decussata. Modiola minima. 



Lima. Myacites striato-granulata. 



Ostrea intusstriata. Pholadomya. 



liassica. Pteromya Crowcombei. 



Plicatula acuminata, Unicardium cardioides. 



Pecten Pollux, Chemnitzia, sp., casts. 



■ , sp. Solarium, sp,, casts. 



Area. Turritella?, sp., casts. 



c. The Insect and Crustacean Beds. — It is of importance to recognize 

 this series of beds, Nos. 79 to 91, in the Camel section. With them we 

 have again another very peculiar and interesting lithological and zoo- 

 logical change in the conditions of the period. Whilst the " White 

 Lias " immediately beneath is throughout a concretionary deposit, 

 without lamination, with a cessation of the conditions necessary to 

 its formation, other beds succeed, which cover a very wide area, are 

 most finely laminated, and thereby indicate very slow deposition. In 

 this change we have another alternation from probably brackish- 

 water deposits into those which are evidently marine, although of 

 estuarine origin. My friend the E-ev. P. B. Brodie, E.G.S., in his 

 ' History of Fossil Insects,' as long back as 1845, pointed out the 

 position in Warwickshire and Gloucestershire "of certain " Insect- 

 limestones ;" and I am pleased to recognize their presence in the 

 above beds, occupying the same geological horizon. 



The numerous testacea which occasionally crowded the waters of 

 the " White Lias " are almost wholly wanting in these beds ; but 

 rarely a few dwarfish Modiola minima are found therein. I have 

 before remarked on the absence of Yertebrata and Cephalopoda in 

 the " White Lias." The latter are still wanting in the Insect-lime- 

 stone ; for although Mr. Brodie alludes to the presence of Aptychus 

 (the operculum of the Ammonite), in beds of Insect-limestone in 

 some of his sections, I have no doubt that they are to be referred to 

 a higher Insect-limestone, in which Ammonites planorUs occurs 

 abundantly. This is the case in Liassic beds passing under the 

 name of the "Black rock" (Nos. 31 to 36 of the section I gave 

 in the Society's Journal for 1861, p. 485) at Beer Crowcombe. The 

 vertebrata, in these Insect-limestones, come in very gradually, and 

 are represented by a few scattered scales of Lepidotus. 



Although my examination of these beds was somewhat hurried, 

 I obtained specimens of Coleoptera and Orthoptera at Camel, and 



VOL. XXIII. PAET I. 2 k 



