of the Goniatite Limestone at Rockford, Indiana. 169 
After the publication of this paper, Prof. Hall was for a time 
inclined to concur, at least in part, with De Verneuil’s views, but 
he subsequently returned to his former opinion, which he has con- 
tinued to maintain, with his usual zeal and ability, to the present 
time. In an important paper recently published by him in the 
13th Annual Report of the Regents of the University of New 
York, he describes a number of fossils from the Rockford Goni- 
atite bed, along with others from the Marcellus shale in New 
York, and refers not only the Black slate, but the Rockford lime- 
stone, which has been supposed to be intercalated in it, to the 
horizon of the Marcellus Shale. 
As the question in regard to the age of the Rockford goniatite 
; n important bearing on the parallelism of our rocks 
with established horizons elsewhere, we have, while investigating 
_ the fossils in the Illinois State Geological collection, carefully 
compared them with a series of specimens from Rockford, In- 
diana, in order to determine whether or not the Goniatite bed at 
that place is represented in our state, and if so, what relations it 
ts to our other rocks. These comparisons have led us to the 
conclusion that it is represented in Illinois, as well as in Missouri 
and Towa, and that it holds a much higher stratigraphical posi- 
hon than that assigned it by Prof. Hall. 
In the first place, we should remark that there is no evidence 
whatever, that the rock under consideration is overlaid at Rock- 
or at any other locality, by any part of the Black slate, 
though we know the slate occurs beneath it there, as well as in 
Again after a careful study of a series of the Rockford fossils, 
we have clearly satisfied ourselves that the limestone from which 
°Y, Were obtained is of the same age as the Chouteau limestone 
characteristic forms of the Chouteau limestone in Missouri and 
Illinois, while most of the others are either identical or closely 
allied. The following is a list of the species from Rockford 
which are known to be identical with Chouteau limestone es 
found in Missouri and Illinois, viz:—Nautilus digonus, M ek and - 
orthen, Euomphalus lens, Hall, Rhynchonella Missourrensis, Shu- 
tard, wryfera Cooperensis, Swallow, (=. semiphicata, Hall) Car 
diopsis radiata,* Meek and Worthen, (= Megambonia Lyont, Hall,) 
and Sphenopterium enorme, Meek and Worthen. 
Ens We y i i i n the genus Cardiom of 
We an this Ha eng: at firet, provisionally, i — ‘a gener ie 
hog we have roposed to — for its re a —! pt pe vB Songer 
: ysis, trom 1 
oS type of the genus Megambonia. 
Am. Jour. Scr—Sxconp Serres, Vou. XXXII, No. 9.—Serr., 1861. 
22 
