Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/161

 Description of Species.

Genus Ammonites.

There are four species described in Mr. Baily's paper, to which I have to add two more, both of which are found in the Cretaceous series in Southern India.

One of the commonest species in this formation is

Ammonites umbolazi, Baily. Pl. III. fig. 1.

A fine and characteristic form, which is not quite distinctly figured in Mr. Baily's paper. The flexuous ribs on the well-preserved shell are not so strongly marked as in the figure, and do not show the least tendency to form tubercles near the back, but gradually die away in all the specimens I have seen. Number of specimens 26.

Locality. Umtamfuna river, South Africa, from bed d.

Ammonites rembda, Forbes. Pl. III. figs. 2, 3.

The whorls are higher than wide ; it possesses a remarkably shaped keel. The shell is well preserved. It has distinct furrows, which are about 6 to the whorl, and are slightly bent near the keel, towards the mouth. The suture is easily detected ; 6 lobes and 6 saddles can be made out. The dorsal saddle is tripartite, the next two lateral saddles bipartite, and the next three only single saddles. The dorsal saddle is double the height of the dorsal lobe ; the lateral lobes are very deep ; the lateral saddle is of the same height as the dorsal one ; but the succeeding ones decrease very rapidly in size. Forbes's figure of this Ammonite is very indistinct ; so also is the fragment which is figured in the ' Memoirs of the Geological Survey of India.'

Ammonites rembda, from Pondicherry, is in every particular like our African specimen. The shell is perfectly smooth, and shows in some places beautiful colours. There are some small specimens amongst the collection, which seem to me to be only young individuals of A. rembda. Number of specimens 3.

Locality. Cliffs on the sea-shore, between the rivers Umtamfuna and Umzambane, in Kaffirland, from bed d. Pondicherry, in India.

Age. Probably Cenomanian. India, Valudayur group.

Ammonites Kayei, Forbes.

An excellent specimen, with flexuous ribs, and a few furrows parallel to the ribs. The ribs are very fine and narrow, and generally divided into two or three at about the middle of the whorls. There cannot be the slightest doubt about the identity of the African specimen with Ammonites Kayei, as it shows all the remarkable peculiarities of Forbes's original specimen in the Collection of the Society.

Locality. Umtamfuna river, from bed d. Pondicherry, west of Penangoor, and north of Odium, in the Trichinopoly district.

Range. Cenomanian. In India, the Valudayur and Ootatoor groups.

Anisoceras rugatum, Forbes. Pl. III. fig. 4.

My specimen shows sharper ribs than the Indian form ; and as it is only a fragment, it does not allow a very distinct specification.

Locality. Umtamfuna river. Bed d.

In India. The Valudayur group.