ZONE OF LYTOCERAS JURENSE. 



141 



Fig. 9. — Section across Bundry Hill, showing its cap of Inferior Oolite. 



dr<: 



a. Inferior Oolite. 



b. Upper Lias. 



c. Middle and Lower Lias. 



d. New Red Sandstone. 



q. Quarries of Oolitic Limestones. 



s. Origin of the springs of water. 



EiG. 10. — Lateral profile of Bundry Hill. 



7. Freestone Building Oolite, 12 feet. 

 6. Fine-grained Oolite 4 „ 



5. Shelly Ragstones 8 „ 



4 k 3. Ruhh'ly Shelly Limestones, 12 „ 

 2. Zone of Harp. Sowerbii 3 „ 



1. Ironshot Pleurotomaria Bed, 2 feet. 



a. Upper Lias Sands 2-3 ,, 



b. Upper Lias Clay 4 „ 



c. Middle Lias 1 „ 



d. Lower Lias 369 „ 



The Oolitic rocks exposed at the summit of the hill belong to the Inferior Oolite, 

 which, in the south of England, admits of a division into three zones of life. The lower 

 resting upon the Upper-Lias Sands has Harpoceras Murchisonce as its leading fossil ; 

 the middle contains a large assemblage of ]\Iollusca, among which the Ammonoida 

 predominate, and these chiefly belong to Stephanoceras Htmphriesianum, Steph. 

 Bronyniarti, and Steph. Brocchii ; the upper zone is characterised by Cosmoceras 

 Parkinsoni, Perisphinctes MartinsH, and Oppelia subradiata, with many Echinidae and a 

 large series of reef-building Corals. These three subdivisions are rarely all found 

 together in the same locality, but the order of their sequence in nature is, as stated, in 

 Dundry. 



1: In the ironshot shelly beds are many Lamellibranch Molluscs and a rich assem- 

 blage of Pleurotomarias. These are covered by the second Ammonite-zone with 

 Stephanoceras Humph riesianum. Many of these are beautifully preserved Ammonoida 

 with the shell entire, the mouth-processes developed, and the Aptychi in sitil, as Stcphan. 

 Humphriesianum , Steph. Brocchii, Steph. Bronyniarti, Steph. Blaydeni, Steph. Gervillei, 

 and others. The Conchifera beds 3 and 4 contain Harpoceras Sowerbii and a large 

 assemblage of Lamellibranchs with Echinidae and Anthozoa belonging to the middle 



