326 



THE WONDERS OF GEOLOGY. 



Lect. IV. 



shells in flint, but only two in chalk. The specimens which I have 

 collected constitute four distinct species. 1. The one to which 

 you have been pleased to give the appellation of 8. Comptoni. 

 2. Spirolinites Lyellii, distinguished by the horizontal chambers 

 one above the other, in the coiled portion. 3. 8. Stolcesii, which 

 I name after our friend Charles Stokes, Esq, ; and this name has the 

 further advantage of pointing out the locality, West Stoke, near 

 Chichester, from which I obtained this unique specimen, and 

 where other spirolinites abound. The fourth you must allow me to 

 designate 8. Mantelli. The distinctive characters of these species 

 are too obvious to require detailed description. The transverse cham- 

 bers in 8. Lyellii {Lign. 60, fig. 1) are a striking peculiarity of structure. 

 I am inclined to believe that there are other species in my collection, 

 but the irregularity in the fractured sections of these minute cham- 

 bered shells, renders it difficult to arrive at accurate conclusions on 

 this point. " Northampton." 



" Castle Ashby, January 1, 1838." 



21. Crinoidea. — The Crinoidea, or lily-shaped animals, 

 are but sparingly distributed in the 

 chalk — a circumstance, as you will here- 

 after find, in striking contrast with the 

 zoological characters of some of the 

 older secondary formations. Stems of 

 Pentacrlnites occur both in the chalk 

 and gait ; and there is a small species of 

 Apiocrinite, which is peculiar to the 

 white chalk.* 



A remarkable cretaceous fossil of this 

 class is the Marsupite, which I thus 

 named from its resemblance, when 

 closed, to a purse. The Marsupite 

 (Lign. 61) was a crinoideal animal, of 

 a sub-ovate form, having the mouth, 

 which was surrounded by arms, or lign. 61. 



tentacula, near the centre. The skele- marsupites milleri; 



7 from the chalk, Briyhton. 



ton was composed of crustaceous, hexa- 

 gonal plates, united by suture, and the arms, which are 

 * Geology of the South- East of England, p. 111. 



