22 L 



as modem reefs are filled in by the erosion and fractiire of 

 the outer walls of the reef; the accumulation of the debris 

 being ground down to mud and sand and washed into the 

 interstices, and plates, and branches of the polypes that are 

 building other parts of the living mass. The Ay ton reef is 

 exposed to about 10 feet in section, and rests upon another 

 reef foi-ming the floor of the quarry, and which descends many 

 feet deeper. The corals are perforated by boring shells 

 Gaslrochoena, and numerous Molluscs that nestled in the creeks 

 and crannies of the lagoon are here entombed as they died. 

 Of these Phasianella striata, Sow., Pecien vemineus, Sow., Pecten 

 lens, Sow., T^irho muricata, Sow., are most conspicuous; besides 

 numerous other shells as Chemnitzia, Nerinma, and other genera 

 of the family Pyro.midaUdce, that had their home in the lagoons 

 of the coral sea. The following species collected from the 

 coralline Oolite of Yorkshire, are preserved in the Museums 

 of York, Scarborough, and Whitby, and hkewise in the cabinet 

 of J. Leckenbt, Esq. : — 



AtSTTHOZOA PEOM the COEAIiLINE OoLITE. 



Montlivaltia dispar, Phil. Stylina tubulifera, Phil. 



Ehabdophyllia Phillipsii, Ed. & Eaime. Isastraea explanata, Goldf. 



Thecosmilia annularis, Flem. Cosmoserisirradians, ^c^w. <fcJ?atme. 



Tliamnastraea concinna, Goldf. Isastrsea iasequalis, Phil. 



u araclinoides, Parh. Cladopliyllia Conybearii, Edw. 



The following list of Cephalopoda has been made for this 

 paper by my excellent fiiend John Leckenbt, Esq., E.G-.S., 

 whose accm-ate critical knowledge of the Palseontology of the 

 Yorkshire Oolites is unsurpassed. He has likewise kindly added 

 a list of the Mollusca found in the Coral Eeefs around Scar- 

 borough : — 



Cephalopoda 



Fotmd in the Coralline Oolite of YorJcshire. 

 Belemnites abbreviatus, Mill. Ammonites Goliathus, d'Orh. 



Nautilus hexagonus Soiv. " perarmatus, Sow. 



Ammonites plicatUis,* Smu. " cordatus, ) g^^^ 



II Williamsoni, Phil. » var. excavatus * 



.' (syn.) Arduennensis, (i'Or&. 



* Not found in the calcareous grit below. 



