British Carboniferous corals belonging to the Fasciculophyllum omaliusi group are usually erroneously referred to the genera Zaphrentis Rafinesque & Clifford and Densiphyllum Dybowski. None of the species usually attributed to Densiphyllum is congeneric with that genus: some, such as D. bradbournense Wilmore, have been shown to belong to the genus Rhopalolasma Hudson (Hudson, 1936, and in press); for others, such as D. rushianum Vaughan, a new genus, Rotiphyllum, is here erected.

The increasing diversity of interpretation of the Jurassic Record is proving very troublesome to teachers and students alike. “To-day, hardly a subdivision of the Jurassic is free of controversy as to its exact scope and nomenclature,” wrote S. W. Muller in a recent laudable attempt to reconcile the differing opinions. More is involved, however, than a mere reconciliation of conflicting views. Our knowledge of the Jurassic Record is as yet far less complete than many geologists realize. For while some of the subdivisions of Jurassic time are in general use by all stratigraphers and have stood the test of time, others are in dispute because they are still based on too local and often defective material, or on too incomplete information; a number remain as much surmises as when they were originally introduced. Any scheme put forward at the present day cannot thus be regarded as the final word in the subdivision of the Jurassic, but merely as a contribution towards an ultimate, ideal, “Standard.”

Most of the specimens described herein have been in my collection for a long time, but lack of opportunity has prevented their being dealt with until now. Several species still require to be worked out and it is hoped to describe them later. Recently my friend, Mr. Stanley Westhead, of Clitheroe, allowed me the privilege of seeing certain specimens he had collected at Coplow Knoll, and one of these, a new Platycrinus, is described here. Some of the species, especially the Poteriocrinids, are assigned to genera whose validity at present is a matter of doubt. In recent years, American workers have made many changes in the nomenclature of the older Carboniferous genera, restricting some and giving new names to others and under the present disturbed conditions it has not been possible to see all these works some of which have a special bearing on the subject. Lack of reference to the majority of these must therefore be expected. In this connection I wish here to thank Mr. Harrell L. Strimple, of Bartlesville, Oklahoma, for much information and for copies of his papers up to date, as well as for other kindnesses. I have also to thank Dr. A. C. Stephen, of the Royal Scottish Museum, for ready access to specimens under his charge and the authorities of the Museum for permission to figure the specimen shown on PI. XI, figs. 5–8. Thanks are also due to Mr. Tot Lord, of Settle, Yorkshire, for the loan of the specimen shown on PI. IX, figs. 7–9.

In 1938 Roman Kozlowski published a preliminary account of a collection of dendroid graptolites and allied forms from the Upper Tremadoc of Wysoczki, Poland, upon which he had been working for many years. All of the thirty-eight species listed were new to science, as were twelve of the seventeen genera, for the reception of which he erected three new orders, Tuboidea, Camaroidea, and Stolonoidea, in addition to Nicholson's Dendroidea. Presumably, no long delay in the publication of the full monograph was anticipated; but the names have remained nomina nuda, and the only clues we have at present to the characters of the new orders themselves are slight.

1. Geological observation provides abundant evidence of fractures in the upper crust, the relative displacements of the sides of a fracture being anything from a few centimetres to thousands of metres. It is generally believed that earthquakes are produced in these displacements, but little attention seems to have been given to the quantitative relations involved. The geologist sees the record of the total displacement, but has no direct information about how long it took to occur, or whether it took place all at once or by several stages. Except in cases where an earthquake has been associated with fracture of the outer surface, and we can say how much displacement occurred up to the time of inspection, he has no means of knowing whether it took seconds, hours, years, or geological periods to form. Even in these rather rare cases the displacement is not more than a few metres, and extrapolation to the larger known faults is impossible. Seismology on the other hand is well adapted to the study of sudden shifts, but the instruments do not record large movements spread over a long time; thus the geological and seismological data are largely complementary. It is known also that a large earthquake is often followed by a swarm of small ones, called aftershocks, apparently from the same focus and continuing for, possibly, several months; there may be a thousand in a single series. The geological displacement observed long afterwards will include those due to all the aftershocks, supposing, as is generally done, that they all are due to shifts on the same fault.