ON THE BRITISH FOSSIL CORALS. 



163 



The Middle Coral-bed is included in the Oolite Marl, and in some localities 

 as at Frith, Leckhampton, Sheepscombe, and others, it contains masses of 

 corals. 



The Upper Coral-reef occupies the horizon of the upper Trigonia Grit, and 

 is very well exposed in many sections. That of Cleeve Hill has yielded the 

 best corals. The following section is oj^en near Frith. Ascending the bank 

 above this quarry for a short distance some fields of arable land are jjassed 

 over, on which are several heaps of the Upper Eagstones, with Trigonia cos- 

 tata, Grijphcva subloha, and other shells of the higher zone. Walking in the 

 direction of i\\e Grove, after passing over the summit of the hill and descend- 

 ing a short distance, a good section of the upper reef may be seen in the 

 Slad ^'alley. 



Section of the Quarry at Worgin's Corner, Upper Zone of Inferior Oolite*. 



Litholo^j. Beds. Organic Remains. 



Masses of Coralline Lime- 

 stone, 4 feet thick. 



Hard shellv Limestone, 

 full of the shells of 

 Brachiopoda, 5 feet. 



Hard shelly sandy Oolite, 

 full of Gryphcea, 6 feet. 



Upper Coral-reef. 



Terebeatula-globata Bed. 



Geyph^a Bed. 



Thamnasircca, Isastrtea, 



Thecosmilia^ Ufagnofia 

 Foj'besi, Stomechiitus tH- 

 termedius, JPecten, Trigo- 

 nia cosfata. 



Terehrafula gJohata, Jihyn- 

 ckciiella spinosa^ Fholado- 

 niya fidicvla, P. SerauUi, 

 Ostrcea, Geniillia, Tri- 

 chites. 



Gryphcfa svbloba, 

 proboscidea. 



Lima 



The remarkable varieties of Thecosmilia gregaria, which resemble the genus 

 Si/mj)JtyIIia and Beterogyra, are found principally in the lower reef, but they 

 exist in the upper also. ISome species appear to be peculiar to the different reefs, 

 but it is unsafe to form lists at present. There is evidently a considerable 

 afhuity between the faunas of the reefs, and there is nothing to indicate any- 

 thing more than a temjiorary absence from, and a return of the species to an 

 area. 



The corals of the Great Oolite are found in the Upper Eagstones underly- 

 ing the Bradford Clay. ISfear Bath large masses of CalamophyUia radiata are 

 associated with the roots, stems, and heads of Apiocrinites rotunclus, Mill., 

 which flourished like a miniature forest on the reef, and luxuriated amongst 

 the polypes uutil the clear water was invaded by a current charged with mud, 

 which destroyed the Ennrinites and the Corals alsot. 



The Coral Eag in Wiltshire is divisible into (1) Upper Calcareous Grit, (2) 

 Coral Eag, (3) Clay, (4) Lower Calcareous Grit. It is in the Coral Eag 

 proper (2) that the Coral-beds are found. 



Of these Mr. Lonsdale J remarks 



* See Dr. Wright's pamphlet 



Oolitic District of Eath," Trans. Geol. £( 



t Dr. Wright, op. cit 

 2. 2ud ser. vol. iii. p. 261. 

 M 2 



