24 Transactions of the Boyal Society of South Africa. 
state of preservation and belongs to the group of the broadly conical 
forms of this genus of which J. de C. Sowerby's Solarium conoideum 
from the Albian rocks of Britain and Europe may be regarded as a 
characteristic example, as opposed to more depressed species repre- 
sented by such a shell as Solarium ornatum of J. de 0. Sower by from 
deposits of similar age. Although built upon the same plan as 
S. conoideum, the shell from Zululand exhibits certain details of 
structure which are of importance for purposes of separation. The 
whorls have a less excavated surface and are not so sharply defined 
at the periphery; the spiral lineations are by no means so numerous, 
and there is an absence of the rows of transversely elongate granula- 
tions which ornament the margins of the whorls both above and 
below the suture in the European shell ; and further, the spiral striae 
are much more obvious on the walls of the umbilical cavity, these 
being seldom present in the conoideum, where only longitudinal 
striations are mostly preserved. Both conical and depressed forms 
of this genus are referred to by Stoliczka as occurring in the Indian 
Cretaceous, but none appear to possess the characters of the present 
shell. 
Under the name of Solarium pulchellum (subsequently altered by 
Gabb to Architectonica bailyi), Baily figured and described a shell 
from the Cretaceous cliffs of South-Eastern Africa (— Pondoland) 
which belongs rather to the depressed and discoidal forms than to 
those with more elevated spires. His species is, however, consider- 
ably smaller than the present specimen, besides having a relatively 
more restricted umbilicus, whilst the upper surface of the volutions 
are not described as being excavated. Mr. Etheridge, jun., refers 
to another form {Solarium sp. indet.) from the Umkwelane Hill 
deposits which in its decussated sculpture is like Baily's species, 
but showing a median conc|avity of the whorls (Anderson's Second 
Eeport Geol. Surv. Natal' and Zululand," 1904, pi. 2, figs. 35-37, 
p. 88) such as is present in the shell now described, although differing 
in its much smaller size and more depressed spire ; and further, no 
umbilical characters are mentioned. The Umsinene Eiver deposits 
of Zululand have yielded S. hedleyi, also described by E. Etheridge, 
(Anderson's "Third and Final Eeport Geol. Surv. Natal and Zulu- 
land," 1907, pi. 5, figs. 10-12, p. 85), but this differs m being of 
smaller form and in its very distinct ornamentation of revolving lines 
of granules interspaced with simple spiral threads. The Albian and 
Cenomanian rocks of Northern Africa (Algeria, Tunis, &c.) have also 
yielded various species of Solarium, which, however, are easily dis- 
tinguishable from the present shell either in their contour or details 
of sculpture. 
