342 Viscount d'ARCHiAC and M. de Verneuil's 



15. Goniatites calculiformis, Bey., loc. cit., PI. II. f. 5. 



This species, of which the volutions are almost entirely exposed, resembles Clymenice in form. Bey- 

 rich has ascertained, by the disposition of the lobes and more particularly by the presence of a dorsal lobe, 

 that it is really a Goniatite ; but we must add, that his figure does not express the fine and elegant striae 

 which are seen on the surface of that shell. 



Common at Oberscheld. 



B. A divided dorsal lobe ; an angular lateral lobe ; and a widely rounded lateral saddle. 



All the Goniatites of this division belong to the Carboniferous system, in which there are scarcely 

 five or six species with a simple dorsal lobe. They truly deserve the name of " Goniatites with a 

 divided dorsal lobe," for the two arms of this lobe which form the beginning of the dorsal saddle and 

 which enclose in their middle another little lobe which may be regarded as a real division of the pre- 

 ceding, are upon the back of the shell and may be called " dorsal lobe and saddle," while in the preceding 

 division the lobe and the saddle called " dorsal" by Beyrich are always upon the side of the shell, and 

 occupy more than half of it. 



The common Goniatites, so numerous in the Carboniferous system, are very rare on the right bank 

 of the Rhine, undoubtedly in consequence of the slight developement of the mountain limestone there. 

 We scarcely know of any, excepting those species which are in a siliceous state, and which are found in 

 the alluvium of the Rhur and the Rhine. These are 



16. Goniatites sphcericus, Mart. ; Petrif. Derbiensis, PI. VII. f. 3, 4. 



17. Goniatites carbonarius, Goldf. ; de Buch, Ann. Nat. Sc, t. 29, PI. II. f. 9. 



This species is found also in the lowest beds of the coal-mines of Werden and Hoffnung in Westphalia ; 

 and appears to be very distinct from the preceding. 



18. Goniatites striatus, Sow. ; Min. Con. PI. LIII. f. 1. 



We refer to this species some impressions that are found in the slate of Bredlar in Westphalia and at 

 Herborn. These impressions, always crushed and deformed, are nearly related in the disposition of the 

 strise and the form of the umbilicus to the species referred to in Mineral Conchology. The longitu- 

 dinal striae are crossed by finer and more close-set transverse striae, forming undulations. The imper- 

 fection of the impressions, however, prevents us from fully identifying our fossil with that of the Mineral 

 Conchology. 



IV. Goniatites whose place is yet uncertain, the disposition of their lobes not being known. 



1 9. Goniatites tuberculosus, nob. Tab. nost., XXVI. f. 4, 4 a, 4 b. 



Shell flattened. Volutions six, one-third exposed, and regularly rounded from the suture to the back. 

 These volutions are furnished with a row of rather elongated tubercles, separated by equal intervals, 

 and placed where the side begins to turn toward the suture to form the inner edge. The surface of 

 the shell is also covered with fine unequal transverse striae, very close-set, which, when they come 

 near the back appear to turn backward to form a dorsal sinus whose concavity is directed forward. 



Oberscheld ; very rare. 



20. Goniatites incertus, nob. Tab. nost., XXVI. f, 6, 6 a. 



Shell discoid, subumbilicated ; volutions six or seven, one-third exposed. Inner edge almost straight, 

 and then the surface of the volutions becomes flattened on approaching the back. Aperture ogi- 

 val. Volutions furnished with twenty elongated, radiating, pliciform, rounded, not prominent 



