CARBONIFEROUS CORALS AND BRACHIOPODS 105 
degenerating into striae over a broad central tabulate area ; 
the septa are prolonged outwards, still strongly marked 
but somewhat thinner, through a broad zone of close 
vesicles ; no intermediate series of septa exists in the outer 
zone, and, owing partly to the indistinctness of the section, 
the bilateral symmetry is not well marked. 
Diameter of the section, 25 mm. ; inner diameter of the 
vesicular zone, 11 mm. 
A vertical section shows broad tabulae, at considerable 
vertical intervals, and indicates a cylindrical corallum. 
The only two specimens are from the top of the Black 
Rock Quarry. 
In the absence of further material of an intermediate 
nature, it is impossible to definitely assign this form to its 
correct position. 
Amplexus. 
Amplexus coralloides, Sow. 
This species is represented by two poor horizontal 
sections ; the one is almost certainly, judging by the 
matrix, from the top beds of the Black Rock Quarry, the 
other cannot be definitely located. 
Lithostrotion. 
Section A. Siphonodendron, McCoy, comprising the 
fasciculate forms. 
Considering the enormous abundance of specimens be- 
longing to this section throughout the whole of the upper 
half of the Carboniferous Limestone Series (i.e. from the 
Great Quarry to the end), it is astonishing how less than 
meagre is their representation in the collection. The 
paucity of material has, however, the immediate advantage 
of rendering any careful analysis of the weight to be 
attached to specific names entirely out of place in these 
notes ; in fact, no safe conclusions can be arrived at except 
by the careful examination, in the field, of the thousand 
