Page:Quarterly Journal of the Geological Society of London, vol. 26.djvu/691

 as Nassa conglobata, on account of the deceptive appearance of its internal cast (a specimen is thus named in the British Museum). Mr. Searles Wood's Pyrula acclinis is shown, by the impression taken from the concave cast of similar specimens, not to have a more elevated apex than P. reticulata, a character which he was led to attribute to it from the deceptive appearance of the internal cast. The specimens of the box-stones and gutta-percha impressions have been placed in the museum of the Society.

The additional facts which I have gathered relative to these nodules since 1867 tend to confirm the conclusion then maintained, viz. that they are of Diestien age, i. e. approximately equivalents of the so-called Black Crag of Antwerp. It also appears very probable that they are of the same age as the Lenham sandstones, which they resemble most closely in condition and contents.

The box-stones of the Suffolk bone-bed represent a period separated by a wide gap from the lied and Coralline Crags, between which and the latter, or true-crag period, the numerous ziphioid and other cetaceans, the great sharks and Trichecodon, had passed away; a few of the mollusca, such as Voluta, Pyrula, and Cassidaria, comparatively abundant in these nodules, still lingered on into the Coralline and Red-Crag period, but attained a larger size, recalling the fact observed with living mollusca, that northern specimens of a species are larger than those from more southern regions.

The most important organic remains which I have found in the Suffolk box-stones, or with the sandstone adherent, may be now mentioned ; a list is given below. Mr. Baker, of Woodbridge, has the left upper penultimate molar of a Trilophodont Mastodon with this sand- stone adherent. Teeth of Ziphioids and fragments of cetacean bone are also found included in this way. The largest tooth of Carcharodon which I have seen from Suffolk is one which I obtained from a " digger," and has the box-stone matrix adherent. Pectunculus glycimeris is the most abundant mollusk, and next to that Isocardia lunulata (Plate XXXIV. fig. 10), the casts of which I have compared with casts from Antwerp specimens. It "will be remembered that Isocardia, though very rare indeed in the English crags, is an abundant shell in the Antwerp Diestien beds. Pyrula reticulata is by no means uncommon amongst the Gasteropods, far more abundant than in the English Crags. Two specimens of a Conus, identified by Mr. Searles Wood with Gonus Dujardinii, one found by the late Mr. Acton, the other by the Rev. H. Canham (Plate XXXIV. fig. 5), are the most distinctive mollusks yet obtained in the nodules. Altogether about 36 species of organic remains have been found at present in the box-stones ; though I cannot say that all these species have been satisfactorily identified. The specimens are placed in the Society's cabinet, and through their farther examination it will be possible to fill in the list more completely.

In the collection of Mr. Whincopp is a crocodilian scute imbedded in this sandstone ; it is clearly of Eocene age, and shows that the destruction of Eocene strata and admixture of their contents had commenced at this period of the history of the East-Anglian area.