The second edition of J. W. Dawson's Acadian Geology (1868) contains some notes communicated by C. F. Hartt. One of these, on p. 643, runs as follows:

“Eocystites primçvus, Billings, Coll. Hartt (Fig. 220). The little plate with radiating sculpture, represented somewhat enlarged in the figure, is regarded by Mr. Billings, to whom the specimens have been submitted, as indicating anew genus of Cystideans.”

In this perfunctory manner, without diagnosis or description, was the genus Eocystites founded. Since a named species was mentioned, that species, E. primçvus, must be taken as genotype, and the generic name is thereby validated.

All geologists are familiar with those changes effected in argillaceous rocks under the influence of heat from igneous intrusions, changes that result in the formation of such rocks as chiastolite-slate, andalusite-hornfels, etc. It is therefore somewhat surprising that the changes produced during the artificial heating of clays should remain comparatively unknown to the body of geologists, although such changes are produced every day on a large scale during the baking of clays for the manufacture of pottery of various kinds. These changes have, indeed, been very little studied from the mineralogical standpoint. It might at first sight be expected that any changes brought about artificially by the action of heat on a clay would compare somewhat closely with those resulting in an argillaceous rock when subjected to contact-metamorphism—at any rate in the normal case of the latter change—when there is no transference of material from the igneous to the sedimentary rock. Yet such is hardly the case; there are certainly points of resemblance, but there are also very notable differences. It must be made clear that the clays used in the experiments to be described were selected on account of their importance for certain industrial uses, and not on account of any special similarity to those argillaceous rocks usually affected by contact-metamorphism. They are therefore clays of a special type with certain chemical characteristics that distinguish them from the more commonly occurring, and therefore more commonly metamorphosed, argillaceous rocks. Nevertheless, the lithological correspondence is close enough to institute certain comparisons.

The area to be described is that part of the Lias outcrop extending from Lincoln southwards to Barrow-on-Soar and Grantham, and includes south-west Lincolnshire and small portions of northeast Leicestershire and east Nottinghamshire (see Map, Fig. 1).

The rocks of this district were mapped by the Geological Survey, and an account of some of them was published in 1885 and 1888; the south-western part of the area has been resurveyed and described in more recent memoirs. A summary of the geology of the area was prepared in 1910 by A. J. Jukes-Browne, but except for these publications the literature is scattered and consists mainly of short papers; details of these are given where they are referred to.

The new genus, Liothyrella, has recently been created by Dr. J. Allan Thomson for the reception of a series of recent and fossil Terebratulids commonly ascribed to the genus Liothyrina. The chief characters upon which the genus is founded are the presence of fine radial ribbing on the surface of the shells and the possession of a short, low, thin, mesial septum in the dorsal valve. In the thickness of the shell, Liothyrella is said to stand between Liothyrina (genotype L. vitrea) and Terebratula, sensu str., all three genera being finely punctate. Thomson takes the; recent Magellanic species L. uva (Brod.) as the genotype of Liothyrella, and includes in the same genus L. uva, var. notorcadensis, Jackson, from Scotia Bay, South Orkneys, and a new species dredged off Tasmania by the Mawson Expedition, as well as two Australian Tertiary species, Terebratula tateana, Tenison-Woods, and T. concentrica (Hutton). He remarks that “probably also many of the other southern species ascribed to Liothyrina will be included here, but the descriptions do not state whether or not a mesial septum is present” (op. cit., p. 44).

Kaolin occurs abundantly in the Federated Malay States in connexion with granite, and is certainly formed on a large scale by weathering. The purest kaolin in large quantity, however, is found as veins in clay above limestone at Gopeng and elsewhere in Kinta, and in quartzite and shales near Tanjong Malim and Kerling. The purity of these veins and the information obtained about those in Kinta when traced down to limestone, lead to interesting considerations about their origin, and the nature of the material in the limestone is a matter of importance in connexion with the possibility of establishing a kaolin industry.