FAUNA OF THE RHONE BASIN. 105 
Scipiomanus indicates that the bucklandian horizon of this basin represents the 
Lower Bucklandi beds of other basins. 
Dumortier divided his zone of Amm. oazynotus into four beds, distinguished 
by their faunas. 
The “ Davidsoni bed” should have been called Striaries bed, since his Amu. 
Davidsoni* is identical with Agas. striaries, The list of species does not enable 
one to synchronize these beds with the Tuberculatus beds of Semur or other 
basins, nor do they show that it is equivalent to any bed above the Upper 
Bucklandi_ beds. 
The Stellaris bed of Dumortier contains, besides the species mentioned in the 
table, Amm. Locardi, a species of Deroceras, and Amm. Birch’, a form of Microde- 
roceras ; both of these, therefore, belong to a family distinct from the Arietida. 
The presence of Birchi, Boucaulliana, and obtusum show that this, and not the so 
called Davidsoni bed, is the equivalent of the bed immediately above the Upper 
Bucklandi beds at Semur. This result confirms our opinion that the David- 
soni bed of Dumortier should be called the Upper Bucklandi bed. 
Dumortier’s Planicosta bed contains Cluniacensis,”? which is identical with Asé. 
Collenoti; and this seems to settle the geological position of this important species. 
Amn. jejunus® seems to be an abnormal or diseased Arn. miserabile; Pellati is 
a young form of Cal. raricostatum ; and armentalis,t if one can trust the aspect of 
the inner umbilical pilx, is a diseased form of Cad. raricostatum. It appears from 
the figure to be similar to the deformed Ann. longidomus ceger of Quenstedt,’ and 
other similar pathological forms, in which the keel and channels have been super- 
seded during growth by pilx crossing the abdomen. 
Viticola (Plate XX XI. Fig. 9-13) is the same as the Johnstonian variety of 
Cal. raricostatum ; Hdmundi (Plate XX XIX.) is the equivalent of the young of Cad. 
nodolianum ; tardecrescens (Plate XX XI. Fig. 8, 4) may be related to Arn. falearies. 
The umbilicus, sutures, and general aspect of the last indicate that it is a form 
of Arnioceras. Oosteri (Plate XXX. Fig. 2-4) is a keeled and channelled form of 
Arnioceras, with distorted pile. 
Amm. plancosta, subplanicosta, and Pauli are all varieties of our Der. planicosta, 
and belong to a family distinct from the Arietide. 
The three upper beds of Dumortier are apparently the equivalents of the 
Birchii or Tuberculatus beds in the table of the Cote d’Or basin. 
The notable facts brought out by this table are as follows. There is a 
regularity in the distribution of the schlotheimian series similar to that in the 
Cote d’Or basin. Caloceras is not so fully represented in the lower beds, and is 
equally deficient in the Bucklandi zone. It is represented by a full list of species 
in the highest beds, with the exception of xodotianum, which is absent. Cul. 
carusense, however, is more fully represented, and Cal. raricostatum has a greater 
number of varieties than in any other fauna. The arnioceran series is not so 
fully represented in the Bucklandi zone, but it is notably richer in forms in the 
highest beds than in any other fauna. Coroniceras is well represented in the 
1 Pl. xxi. fig. 1-4. 2 Pl. xxv. fig. 8-10. S° Pl Sexi, fos 0-6. 
+ Plea hee 1; 2. 5 Die Amm. d. Schwab. Jura, pl. vi. fig. 3. 
14 
