472 Notices of Memoirs—O. H. Howarth—Volcanic Structure. 
detected in the Syrian beds. Belonostomus, however, is common to 
the two formations, one species having been described from Mount 
Lebanon under the name of Rhinellus laniatus. 
Of Physostomous Teleosteans, the great early families represented 
in the Chalk of England and the Upper Cretaceous of North America 
by Portheus, Ichthyodectes, Protosphyrena and Pachyrhizodus, are 
quite unknown in the deposits of Mount Lebanon; but in the latter 
locality Enchodus is abundant, having been described under the 
synonym of Burygnathus, and this is accompanied by a closely-allied 
genus, Hurypholis, only differing in the possession of a few dermal 
scutes. The English Pomognathus may also be regarded as repre- 
sented at Mount Lebanon, for the so-called Phylactocephalus merely 
differs in the presence of extremely delicate minute scales, which 
would not be preserved in a matrix of the nature of the Chalk ; and 
Aspidopleurus (Mount Lebanon) possesses scutes indistinguishable 
from the detached examples long known in the English Chalk under 
the name of Prionolepis. Dercetis, also, is met with abundantly in 
the Syrian beds, being described under the synonym of Leptotrachelus. 
Among Elopine Clupeoids, some undescribed forms occur in the 
English Chalk, and one from Mount Lebanon has been erroneously 
assigned to the genus Clupea (C. Lewisii); and the supposed 
Salmonoid, Osmeroides, is common to the two formations, though 
inferior in size at the last-named locality. In the Syrian deposits, 
however, there are many more specialized Physostomi, such as 
Cheirothriz, Spaniodon, Opistopteryx, Rhinellus, Scombroclupea, Diplo- 
mystus, and Clupea, not represented among English Chalk fossils. 
Among Physoclystous Teleosteans but few genera are common to 
the two formations under comparison. Hoplopteryz, with perhaps 
Beryx, represents the Berycide in both localities; but only a single 
imperfect specimen from the English Chalk can yet be assigned to 
any higher type, namely, Platax (?) nuchalis. At Mount Lebanon 
more specialized Physoclysti are numerous, as Platax, Imogaster and 
Pycnosterina ; although to the latter have been erroneously assigned 
certain extraneous forms, including at least one well-marked Berycoid, 
the so-called Pycnosterina Lewisit. 
The conclusion is thus arrived at, that in those respects in which 
the Lebanon fish-fauna differs from that of the English Chalk, it 
exhibits greater specialization. Considered alone, therefore, it is 
distinctly of a more modern type than the latter, although the beds 
in which it occurs are regarded, from other evidence, as being of 
Senonian or even Turonian age. 
VIII.—On tue Recent Voucanic STRUCTURE OF THE AZOREAN ARCHI- 
petaco. By Ospert H. Howarrs. 
I \HE object of the author’s notes upon the relation of the Azorean 
group to the other islands of the West Atlantic is to indicate a 
line of inquiry by which some approximation may be made to the 
intervals separating the great eruptive changes; and determining 
any modifications in the type of flora during that important succes- 
