lxxii DESCRIPTIVE REMARKS, 
irGaaeline 
PreRopoDa. 
SOA 
ZL 
ZZ 
Creseis aciculata (recent) Cleodora pyramidata Conularia quadrisulcata 
Atlantic. (recent) Atlantic. ( fossil), reduced to one- 
(Woodward’s Mollusca.) (Woodward’s Mollusca.) fourth of natural size. 
Carboniferous Limestone, 
and Coal Measures. 
(Woodward’s Mollusca.) 
CrePpHALopopA were at their maximum development during the 
Carboniferous Limestone period. Vautilus dorsalis, fig. 7, is a large 
and frequent Carboniferous Limestone species in England and Ireland; 
there are several other species of this genus in the Limestone; some 
of them being flattened forms were named Disecites by Professor M‘Coy. 
The straight and curved forms of the Orthoceratide are well repre- 
sented in the Carboniferous Limestone by many species of the genera 
Orthoceras, Gomphoceras, and Cyrtoceras. Orthoceras cinctum, fig. 8, a, b, 
ranges from Middle Devonian to the Carboniferous Limestone. 
Recent and fossil examples of spiral and straight forms of Cepha- 
lopod shells are shown on the next page at fig. 18. A. The pearly 
Nautilus (recent); and B. Orthoceras (fossil) both being sections of 
the shell to show septal divisions and siphuncle. 
Goniatites belonging to the Ammonitide also attain their maxi- 
mum development in Carboniferous strata; many species are enu- 
merated both in the Limestone and Coal Measure shales. The one 
we have selected for illustration, Goniatites sphericus, fig. 9, a, b, 
believed to be identical with that named G. crenistria, occurs in pro- 
fusion both in the Limestone and the Coal Measure shales, more espe- 
cially in Ireland. As far as British strata are concerned, Orthoceras 
and Goniatites disappear with this formation. 
