The rarity and imperfect preservation of the fossils in the upper part of the Lower Greensand, in the south-east of England, has always added considerably to the difficulties in the study of that series. The Atherfield Clay and the Hythe Beds both have well-marked faunas, though fossils are often absent from the latter. The palæontological evidence is, however, much less satisfactory in the case of the two uppermost of the four divisions into which the Lower Greensand is usually divided. A fair number of fossils occurs in these at Folkestone, but further to the west the lithological nature of the beds changes, and fossils are found in but few localities.

It is evident that neither Barrande nor Davidson, who maintained the opinions I have summarized till the last in their publications, were able to recognize the evidence deducible from a study of the Brachiopoda favourable to the theory of their evolution.

Thanks solely to the labours of the late Oswald Heer, the fossil insect-fauna of Œningen is better known than that of any other locality or horizon in the world. But it is by no means so well known as it should be; for although Heer, in his latest enumeration of the specimens seen by him (Urwelt der Schweiz, 2e Aufl. 1879, p. 383), repeats precisely the same figures he has already given in 1861 (Recherches sur le climat du pays tert., p. 197), indicating in an interval of eighteen years no addition to his material (over 5000 specimens), his repeated additions to the number of species from that locality show that he had not fully worked over what he had. Indeed, thirty years ago, I arranged for exhibition in the Museum of Comparative Zoology at Cambridge a collection of nearly one hundred and fifty named species secured by Prof. Louis Agassiz from Heer, of which more than forty still remain undescribed; there are also a considerable number of merely nominal species enumerated by Heer in his Urwelt der Schweiz and elsewhere, duly catalogued by me in my Index to Fossil Insects (Bull. U. S. Geol. Surv. No. 71), but as yet neither described nor figured. In addition to this it may be noted that in the enumeration referred to above Heer mentions 543 species of beetles, while less than 270 nominal species have yet been published from Œningen, and only seven species from the Swiss Miocene, included in the enumeration.

For a considerable time past I have been engaged, in collaboration with Mr. E. J. Garwood, in an investigation of the rocks in contact with the Whin Sill. The results of our joint work, geological, petrographical, and chemical, will be published in detail in due course. In the meantime there are some special observations, made on some of the rocks in question, which have more or less bearing on some of the points dealt with in a paper I contributed to the Geological Magazine last year (Geol. Mag. 1894, pp. 36 and 64).