296 Mr. Weaver on the Structure of the South of Ireland, 
possess a divided dorsal, and three a simple dorsal lobe. Of 
the 33 species, 30 are first made known to us by Professor 
Phillips ; only three of them having been previously noticed 
by authors, namely, Goniatites sphcericus (Mart.), Go7i. Lis- 
teri (Mart.), and Gon. Henslowi (Sow.) 
I have no doubt, that Professor Phillips, who is so well 
qualified for the task, will give due attention to this subject 
in Devon and Cornwall ; and it will be interesting to learn 
in what degree the Goniatites of the carboniferous limestone 
in North Devon, near Barnstaple (e. g., at Swimbridge, where 
they abound), differ from those found in the transition di- 
stricts of South Devon and Cornwall. The same subject de- 
serves attention in Ireland^^. 
To M. Von Biich we owe the first precise distinction be- 
tween Nautili and Ammonitesf. The range of the former 
extends, it is well known, from the oldest to the most recent 
of the fossiliferous strata, the genus being still in existence. 
The Ammonites, on the other hand, though equally ancient 
in origin, do not in their range pass beyond the limits of the 
cretaceous group. To the same distinguished naturalist we 
owe the distribution of the Ammonites into 14? families^, the 
first and oldest of which, the Goniatites^ are characteristic of 
the transition and carboniferous epochs, not extending be- 
yond the coal formation ; the second, the Ceratites^ appear 
confined to the muschelkalk ; while the remaining 12 fami- 
lies are distributed through the series of formations extending 
from the lias to the chalk inclusive. But we are indebted, 
primarily, namely, in 1828, to Professor Bronn of Heidel- 
berg, for the important observation so conducive to the di- 
stinction of formations, that no Ammonites wdth denticulated 
lobes have been found in strata of the transition and carboni- 
ferous seras, such being confined to the formations of a later 
origin. This remark was publicly made known by Von 
Buch in 1829, nearly at the same time that M. Elie de Beau- 
mont was preparing to announce a similar observation made 
by himself; and the remark was shortly after confirmed and 
generalized by Count Munster §. 
* Count Munster considers his Goniatites ovatiis, found at Gottendorf 
and Schleitz in the Fichtelgebirge, to be the same as the Ellipsolites {Nau- 
tilus) ovatus of Sowerby, which occurs in the Cork band of limestone. 
And he inquires whether some other species described as Nautili by Mr. 
Sowerby might not prove to be Goniatites. 
f Annates clcs Sciences Naturelles, tome vii. premiere serie, 1829. 
j Annates clcs Sciences Naturellcs, tome viii. 1829; and Transactions of 
the Royal Academy of Sciences of Berlin, April 1, 1830, Utber die Ammo- 
niten in den dllercn Gebirgs-Schichten. 
§ Von Buch, iiber Goniatiten, December 15, 1831, in the Transactions of 
