In previous publications the writer has announced the discovery of Jurassic Mammals in America, and has given brief descriptions of the more important forms brought to light. Since the last article on this subject, a large amount of new material has been secured, including representatives of several hundred individuals. The remains consist not of lower jaws alone, but of various portions of the skull, and not a few vertebræ, limb bones, and other parts of the skeleton.

The now well-known Liassic Acipenseroid fish Chondrosteus acipenseroides was named by Agassiz in 1843, but not described by him. It subsequently formed the subject of an elaborate memoir by Sir Philip Grey-Egerton, Bart., in which, besides giving a minute account of the structure of the genus, he named two additional species—C. pachyurus and C. crassior. Putting the results of Sir Philip's investigations as briefly as possible, he maintained that while “in all essential points” Chondrosteus resembled the recent Sturgeon, nevertheless in certain others, and notably in the structure of the opercular and hyoid regions, it constituted a transitional form towards the more ordinary Ganoids. Moreover, the skin of the body presented the same naked condition seen in the recent Polyodon.

Description.—Shell conical, turrited; apex acute; spiral angle regular, whorls 8–9, angularly carinated anteriorly; sutures wide and deep; each whorl bears 3 spiral rows of equally spaced but unequal neatly rounded tubercles; the anterior of these, which are much the largest, are set on the carina; the middle row consists of fine granules, whilst the nodules of the posterior row, which adjoin the posterior suture, are intermediate in size and half-way between the other two. Fine, close-set curved striæ of growth cross the whorls transversely, but are scarcely discernible even with a lens, except on the last whorl of well-preserved specimens.

The accumulations of drift in the vicinity of the town of Sudbury have been described by Mr. Whitaker in the Geological Survey Memoir upon the N.W. part of Essex and N.E. part of Herts, etc.; and additional notes are given by the same author in the Memoir upon the Geology of Ipswich, etc. Since the appearance of these memoirs the sections have altered considerably, and one of the exposures is of such interest, that a record of it seems to me desirable, as in a few years it will be doubtless destroyed, and one more link in the chain of facts which have to be considered in attempting to account for the mode of formation of these drifts will have disappeared.

Introductory.—The writers having had occasion, in company with Mr. Davies, to examine the greater number of the remains of English fossil Emydine and Pleurodiran Chelonia in the collection of the British Museum, with a view both to their rearrangement in the cases and the determination of their affinities, and having in the course of such examination been enabled to add several genera to the British fauna, as well as to make certain emendations in regard to the age and affinity of some of the previously-described forms, have thought it advisable to put their observations on record.