The position in Belgium of this formation above the older Eocene group is well seen in the small hill of Pellenberg, rising abruptly from the great plain, half a mile south-east of the city of Louvain, where I examined it in company with M. Nyst in 1850. At the top of the hill, a thin bed of dark greyish green tile-clay is seen 1-1/2 foot thick, with casts of _Nucula Deshaysiana_. This clay rests on 12 feet of yellow sand, separated, by a band of flint and quartz pebbles, from a mass of subjacent white sand 15 feet thick, in which casts of the Kleyn Spauwen fossils have been met with. Under this is a bed of yellow sand 12 feet thick, and, at a lower level, the railway cuttings have passed through calcareous sands like those of Brussels, in which the _Nautilus Burtini_, and various shells common to the older Eocene strata of the neighbourhood of London, have been obtained. Every new fact which throws light on the true paleontological relations of the strata now under consideration, (the Upper Marine or Fontainebleau beds of the Paris basin, 1. _b_, p. 175.), deserves more particular attention, because geologists of high authority differ in opinion as to whether they should be classed as Eocene or Miocene. Professor Beyrich has lately described a formation of the same age, occurring within 7 miles of the gates of Berlin, near the village of Hermsdorf, where, in the midst of the sands of which that country chiefly consists, a mass of tile-clay, more than 40 feet thick, and of a dark blueish grey colour, is found, full of shells, among which the genera _Fusus_ and _Pleurotoma_ predominate, and among the bivalves, _Nucula Deshaysiana_, Nyst, an extremely common shell in the Belgian beds above-mentioned. M. Beyrich has identified eighteen out of forty-five species of the Hermsdorf fossils with the Belgian species; and I believe that a much larger proportion agree with the Upper Eocene of Belgium, France, and the Rhine. On the other hand, eight of the forty-five species are supposed by him to agree with English Eocene shells. Messrs. Morris, Edwards, and S. Wood have compared a small collection, which I obtained of these Berlin shells, with the Eocene fossils of their museums, and confirmed the result of M. Beyrich, the species common to the English fossils belonging not simply to the uppermost of our marine beds, or those of Barton, but some of them to lower parts of the series, such as Bracklesham and Highgate. On the other hand, while these testacea, like those of Kleyn Spauwen and Etampes, present many analogies to the Middle and Lower Eocene group, they differ widely from the Falun shells,--a fact the more important in reference to Etampes, as that locality approaches within 70 miles of Pontlevoy, near Blois, and within 100 miles of Savigne, near Tours, where Falun shells are found. It is evident that the discordance of species cannot be attributed to distance or geographical causes, but