FROM THE ZONE OF AMMONITES PLANORBIS. 



5 



No Tabulate nor T erf orate genera have been discovered ; yet as they existed both 

 in palaeozoic times, and in formations more recent than the Lias, they doubtlessly will be 

 found. 



The multitude of branching ThecomilicB, stunted Montlivaltice, and small-caliced 

 JstrocoBJiicE, give the peculiar facies to the Coral-fauna of these members of the Lower 

 Lias. 



IL Corals from the Zone of Ammonites planorbis. 



The yellow shale in the section at Street which contains Avimonites planorbis and 

 Ichthyosaurus intermedins has yielded a large and well-preserved specimen of the genus 

 Septastreea} At Binton there are said to be Corals in the " Guinea ^ bed," but no 

 specimens could be obtained. 



Section— y^POi^O/S'^. 

 Family— ASTRiEID^ . 

 Division — Faviace^. 

 Genus — Septastr^a.^ 

 1. Septastr^ea Haimei, Wright, sp. PI. I, figs. 1 — 5. 



The corallum is massive, tall, club-shaped, and rather gibbous. The shape is 

 generally sub-cylindrical, the base is small and conical, and the top is large and convex. 



The calices cover the corallum, are very numerous, and are separated by rather thick 

 and united walls. The calices are irregular in size, shallow, and more or less polygonal ; 

 and they have a tendency to elongate at one end, as well as to divide fissiparously. 



The septa are irregular in size, shape, and number ; they are small, unequal, rather 

 distant, and the only ornamentation is an ill-defined swelling here and there. They are 

 not exsert ; the smallest reach but a slight distance from the wall, but the larger 

 occasionally reach the centre of the calice and unite. 



Fissiparity is produced by two large septa stretching across the calice and developing 

 others from their sides. The septa vary in number, from thirty to forty, but no cyclical 

 arrangement is distinguishable. The endotheca is rather plentiful. 



1 2 Wright, ' Monogr. Oolitic Asteriadae, Pal. Soc.,' p. 5 and p. 10. 

 * ' Hist. Nat. des Corall.,' vol. ii. 



