Next to Hypsilophodon it was Polacanthus which attracted my attention. A careful study soon showed that, after the death of the animal, the remains of some Crocodilian had accidentally become commingled with this Dinosaur. Besides this, some pieces, namely, the back part of a skull and a cervical, showed remarkably Iguanodon-like characters, and the same is also true of the pubic bone described by Seeley in 1892 as belonging to Polacanthus.

As I intend pointing out further on, and as has also already been done by Seeley, Polacanthus was constructed essentially after the Struthiosaurus plan, and this is the reason why this Iguanodon-like basi-occipital has to be removed from the Polacanthus remains.

Continuing the notice of Herr H. Monke's paper on the Trilobite-bearing limestone slabs of Yen-tsy-yai, the author observes:—The very dense and solid, slightly arenaceous limestones of Yen-tsy-yai consist of horizontal slabs (from 1–2½ cm. thick) of a dark bluish-grey colour, [p. 109] Whilst showing no traces of fossils in their interior, the limestone slabs are on one side (as shown on pl. ix) often completely covered with the remains of Trilobite carapaces, besides which are found only isolated very minute shells of Brachiopoda. Between them are here and there irregular, lengthened furrows, which may be the tracks of the Trilobites; on the corresponding opposite pails of the slabs are similarly shaped vermiform protuberances. It follows that the fossiliferous side is to be considered as the natural upper part of the slabs. In a certain number of the slabs either both sides or one only are covered besides by a thin argillaceous stratum, which equally contains, though less frequently, delicate remains of fossils; in all the other slabs the fossils present themselves en relief and often rest on a small base of limestone, and therefore convey the impression of having been originally covered by a thin argillaceous stratum, which later on was washed away by water.

The fragments of partially weathered chert from North China sent by the Rev. S. Couling, unfortunately without indication of the particular locality or formation where they were collected, are of whitish, slate-grey, or pinkish aspect, and in two instances show traces of banded structure. They consist of cryptocrystalline or microcrystalline silica with small areas in which the silica is of a fibrous chalcedonic character. Remains of organisms can be distinguished in each of the four microscopic sections which have been prepared, but they are generally so shadowy and indefinite that their nature cannot be satisfactorily determined. Some portions of slide marked A are crowded with slender, straight, or slightly curved linear bodies, about .11 mm. in length by .01 mm. in width, which in places have a sub-parallel or sheaf-like arrangement. They might be supposed to be sponge spicules, but in their size and disposition they seem to differ from any fossil spicules with which I am acquainted. Slide C largely consists of numerous small, rounded, oval, and conical forms without walls, ranging from .1 to 1.7 mm. in diameter. In outline and in size many of these bodies might be compared to Radiolaria, but as they are now not sharply delimited from the clear matrix, but by a granular structure-without other features, it would be rash to assert, save upon further evidence, that they belong to these organisms. In slide D there are some well-defined circular bodies, .03 to .1 mm. in diameter, with clear solid walls, and not infrequently a central spot in each, which very much resemble transverse sections of sponge spicules, and it is possible that this may be their true nature, but some doubt rests on this owing to the apparent absence in the slide of longitudinal sections of spicules.

When revisiting Speeton on the 6th of April, 1905, I was surprised to find that the exposures of Bed (Hunstanton) Chalk on the beach at the locality (about 500 yards east of the mouth of Speeton Beck) where the excellent vertical section described by Mr. W. Hill occurs were almost invisible owing to the accumulation of boulders of white chalk by which they were covered. At length I found a small exposure of Eed Chalk near low water mark and, within 3 or 4 yards to north of it, that is, seawards, I came across a reef of chalk in well-defined beds, each perhaps 6 or 8 inches thick, weathered to a brownish or drab tint. This chalk, when freshly fractured, was hard and white, quite unlike the true Red Chalk, although practically at the same level. The prevailing dip of the white chalk of the reef was from 25° to 28° to W. 40° S. mg. (= W. 57° S. true), and the length of the exposure along the strike, so far as the limited time at my disposal would allow me to observe, was 65 paces (say 55 yards), the width in the direction of dip being 16 paces (say 13½ yards). So far as I have been able to gather, this reef of white chalk to seaward of, and apparently dipping beneath, the Red Chalk has not been described. Four possible explanations of its occurrence may be suggested.

Stomatopoba Antiqua was first described and figured by Haime from specimens occurring on Gryphæa in the Lower Lias of France. I have not been able to find any record of an English specimen except that in the Survey memoir on the Lias of England and Wales. But recently several specimens of a Stomatopora resembling S. antiqua, Haime, were found in the collection of the late Mr. E. F. Tomes. The fact that all the specimens were encrusting Gryphæa is remarkable; for though many hundred specimens of various molluscs from the Lower Lias were searched, and of these all sorts of oysters with especial care, Gryphæa was the only form encrusted by Stomatopora.

Unsolved geological problems, or what perhaps may be better described as obscure points in geological history round which conflicting hypotheses have arisen, are to be found in many parts of our Islands, but Devonshire seems to be an usually prolific field for them. Mr. W. H. Hudleston, F.R.S., in his presidential address to the Devonshire Association in 1889, enumerates nine questions propounded by Pengelly in 1868 as still requiring special consideration in the future. Of these possibly three may be said to have nearly or quite got beyond the controversial stage, but in the meantime others have arisen, and it would thus appear that the undecided position of numerous points demanding further investigation is the normal condition of a science in the developmental stage.