207 
Stephanoceras Brackenridgii, Sow. Stephan. Deslongchampsii, d’ Orb. 
" Brocchi, Sow. “ Gervillii, Sow. 
" Brongniarti, Sow. " Humphriesianum, Sow. 
" coronatum, Brong. u Sauzei, d’Orb. 
The group which Stephanoceras macrocephalum, ScuuotH> 
represents, appears to stand apart from the preceding forms, 
for all these shells are characterised by their globose figure, 
arising from the extreme involution of the shell, the narrow- 
ness of the umbilicus, with its steeply-inclined walls, and a 
remarkable lobe-line. The siphonal lobe is extremely long, and 
much broader, but not longer nor downward extending than 
the principal lateral; the second lateral is smaller, and reaches 
to the umbilical border. Such is the condition of the lobes in 
Stephan. modiolare, Lum. This group has very few species in 
the European rocks. They all occupy a very limited horizon, 
commencing with Stephan. macrocephalum in the Cornbrash in 
England, and in the same horizon in Germany. They are 
found likewise in the Kelloway Rock, and in the dark clay bed 
which lies above the Kelloway, and belongs to it. 
The Indian species are numerous and well-preserved, twenty- 
three species have been figured and described from the Kacch 
Jura, by Dr. W. Waacen.* “Of these species those identical 
with European forms occupy also in Kacch, as in Europe, the 
true ‘Macrocephalus-beds.’ The other species, however, range 
from the uppermost beds of the Pachum group up to the 
Kuntkote sandstone, i.e., from the highest beds of the Bath 
to the uppermost beds of the Oxford group, each of them keeping 
in the meantime strictly to its own layer.” 
“Long since it was apparent that the group of the Macro- 
cephali was one of the most important among all the Jurassic 
Ammonites, not only because they characterised a well-defined 
horizon in the European Jurassic series, but also very nearly 
allied forms had been found over the whole world, and it was 
to a certain degree supposed that these also ought to signify 
about the same geological time, indicating for the beds in 
© “ Jurassic Cephalopoda Palzontologia Indica,” p. 108. 
