conferta Duncan 
PI* fig. 
1863. Isaatraea conferta , Duncan, Quart. Jour* Geol. Soc* London, 
Vol. XIX, p. 422, PI. XIV, fig. 2. 
1867. Isaatraea conferta , Duncan, Quart. Jour. Geol. Soc. London, 
Vol. XXIV, p. 25. 
Original description: 
M Corallites very close, tall, slender, straight, and pris- 
matic; a transverse section shows the wall to Vevery thin. The 
( . L& %* & - j 
breadth of the corallites varies from 3/l0 to l/lG inch. Septa 
very numerous, linear; the primary extend to the centre of the 
corallite, the secondary less so, and the others join the larger 
septa at a very acute angle; all are very slender and excessively 
crowded. There are eighty-two septa in the larger corallites, 
sixty in the smaller. The septa of one corallite do not join 
those of the next, hut end sharply at the wall. En do thee a plain- 
ly exists, linear, appearing, in transverse section, to divide 
