102 EXPLANATION OF THE PLATES. 
2. Simple cylindrical corallum, showing circular accretion swellings, a portion 
being removed to exhibit the numerous septe and vesicular dissepiments. 
Carb. Limest., Kilvarnet, Co. Sligo. Mus. G. 8. I. 
Carsonrrerous LIMEsToNy.—An abundant coral in the Lower Limestone 
and shales, especially in the North of Ireland, where they occur of very 
large size. 
Fic. 5.—a, 6. Ampiexus corattorpEs, Sowerby. 
Min. Conch., vol. 1., p. 165, pl. Ixxii. Brit. Foss. Corals, p. 173, pl. xxxvi., 
figs. 1 a—e. 
Original. Reduced to half natural size. a. Portion of a simple cylindrical 
“cor allum, irregularly twisted and covered by circular accretion swellings 
and vertical lines, the outer edge of the septa. At its lower end are 
shown the closely set tabule and septe. 
b. Section showing one of the tabule with septal markings round its outer 
edge, corresponding to the septal fossula. Carb. Limest., Rathkeale, 
Co. Limerick. Mus. G. 8S. I. 
CARBONIFEROUS LimEesToNE.—This Coral is most abundant in the Carb. 
Limest. of Ireland, especially the Lower Limestone of the South. It is 
also met with in Derbyshire, Yorkshire, and the Isle of Man. 
Fie. 6.—a, b. Lrruosrrotion striatum, Fleming. 
British Animals, p. 508. JZ. basaltiforme, Brit. Foss. Corals, p. 190, pl. 
XXXvlil., fig. 3. 
Original. a. Group of compound hexagonal corallites, showing where frac- 
“tured the closely arranged septa. 06. Horizontal surface of astreiform 
corallites, showing their closely united and consequently hexagonal ar- 
rangement. Carb. Limest. Cookstown, Co. Tyrone. Mus. exsaia 
Carponirerous Limrsrone.—This very common, and well marked species, 
is frequent in various parts of England, North and South Wales, and 
Ireland. It sometimes occurs in “stools” hemispherical in form, and 
several feet in diameter. 
Fie. 7.—a, 6. Litnosrrottion Porrrocki, Milne Edwards. 
Astrea irregularis, Portlock, Geol. Rep., p. 838, pl. xxxiil., fg. 3. Litho- 
strotion Portlocki, Brit. Foss Corals, p. 194, pl. xli., fig. 1 
Original. a. Upper surface of a anal group of compound and irregular 
Pheeagonally arranged corallites. One of the calices enlarged showing 
septa and prominent columella. In red earthy Carb. Limest. Kildress, 
Co. ‘Tyrone. Mus. G. 8. I. 
Carsonirerous Limestons.—Derbyshire ; North Wales, Bristol, Queen’s 
Co., and county Tyrone, in massive bunches. 
As there i is some difficulty i in defining the genera Lithostrotion and Lithoden- 
dron, we have included, under - the first named genus, all those species 
in which the corallites closely adhere and are compressed together, as 
in the two here figured (figs. 6 and 7), whilst that of Lithodendron 
include those corals which are fasciculate, uncompressed, and only 
coalesce, or unite at intervals, as in the two following species (figs. 8 and 9. 
