CORALS FROM THE CORAL RAG. 75 
The corallites are very tall, and the calices vary somewhat in size in the different 
specimens which have come under our observation; in small adult individuals their 
width (at the great diagonal) is about two and a half lines, and in the large ones scarcely 
more than three lines. 
The genus /sastrea comprises a considerable number of species, the list of which has 
been given in our above-mentioned work. In order to avoid umecessary details, we will 
therefore only add, that 7. od/onga is easily distinguished from the other British fossils 
belonging to the same generical group, by the thickness of its walls, and the strong lateral 
granulations of the septa. By its general aspect this coral bears some likeness to the 
Tsastrea polygonalis, a fossil of the Muschelkalk, of which the cast only has as yet been 
found; but in this last-mentioned species all the septa of the fourth cyclum are well 
developed. 
Tsastrea oblonga has been met with only at Tisbury, Wiltshire. The specimens which 
we have examined belong to the collections of the Geological Society of London, the 
Museum of Bristol, the Museum of Paris, Mr. Bowerbank, and Mr. Stokes. 
CHAPTER IX. 
CORALS FROM THE CORAL RAG. 
The Coral Rag, as may be inferred from its name, is a deposit most abundant in fossil 
corals ; but the number of species found in this Formation is by no means proportionate to 
that of the specimens met with. The British species are indeed very limited ; and, although 
we have had access to all the richest paleontological collections in England, we have only 
seen fourteen species of true corals belonging to this portion of the oolitic series. ‘Twelve 
of these are Astreide, and two Fungide ; five of these species are also found in the Coral 
Rag of France and Germany; the nine others are, as yet, peculiar to England. One 
(Thamnastrea concinna) appears to exist also in the Great Oolite, and probably even in the 
Inferior Oolite ; but most have not been met with in any other Formation. 
The principal fossiliferous beds, from which these corals have been obtained, are 
situated at Steeple Ashton, in Wiltshire, and Malton, in Yorkshire. Some species have 
also been found at Hackness, in Oxfordshire ; at Osmington, near Weymouth ; at Upware, 
in Cambridgeshire, &c. 
1 Astrea polygonalis, Michelin, Iconogr., tab. iii, fig. 1. 
