William Dickson Lang

Shales-with-‘beef,’ a Sequence in the Lower Lias of the Dorset Coast.

Shales-with-‘beef’ was the name given to some 70 feet of Lias on the Dorset coast, lying above (53) Table Ledge and below (76 a) the Birchi-Tabular. The beds consist of paper-shales, marls, indurated bands, and limestone nodule-beds, with numerous, more or less impersistent, interbedded seams of fibrous calcite, called ‘Beef’ by the Officers of the Geological Survey. Descending to the beach at Charmouth, and there forming reefs on the foreshore, the Shales-with-Beef are the most accessible Lias of that place. Yet they are, perhaps, the least known of all the beds. This is doubtless because of the generally unsatisfactory condition of the fossils found in them, and their consequent worthlessness on the one hand to the native, who finds no sale for such fragmentary and friable remains as the fossils present; while, on the other hand, the geologist seldom finds specimens more than approximately identifiable, and generally obtains completely satisfactory examples from but three or four horizons. Sir Henry De la Beche described the Lias of this coast nearly a century ago; and, although he generally under-estimated their thickness, the subdivisions that he then made can be approximately correlated as follows, at any rate those five which lie above the Blue Lias limestones:— (5) Irregular bed of Limestone, with nodular concretions, frequently containing ammonites; 2 feet=Stellaris beds (87–89). (4) Slaty marls, with several thin beds of indurated marl; 67 feet = Black Marl series above Birchi-Tabular and below Stellaris beds (77–88). (3) Slaty marls containing small crystals of selenite; 32 feet Shales-with-Beef (54–76).

The Black Marl of Black Ven and Stonebarrow, in the Lias of the Dorset Coast

The Black Marl series of the Dorset coast was so named by the officers of the Geological Survey to include the shales and limestones lying above the stone-beds of the Blue Lias and below the pale marls of the Belemnite Beds. I have already given a detailed account of the Shales-with-‘Beef’—the lowest part of the Black Marl series. But a detailed account of the sequence above the birchi bed is much needed; and, although our knowledge of the contained fossils and their order of occurrence is still incomplete, yet a particular description of these horizons as represented on the Dorset coast should help to unravel the sequence in the corresponding Lias of other areas, especially in view of the amount of work which is now being done on the Lias, and of the use already made of the Dorset sequence in such work. In this connexion much has been heard of non-sequences. It is hoped that this paper will show the importance of this principle in interpreting the Lias; yet to what error it may lead if rashly applied. I need hardly indicate how barren the detailed observations and descriptions of the paper would be without the accurate (even if approximate) determinations of the ammonites. Indeed, except from the view-point of lithology, detailed description of the beds is only necessary in order that the exact positions of the contained fossils may be recognized. The experience and the knowledge reuired to determine specimens as poorly preserved as most o those collected

The Belemnite Marls of Charmouth, a Series in the Lias of the Dorset Coast

Anyone standing on the beach between Charmouth and Lyme, and looking up at the bluffs and precipices of Black Ven, is struck by the contrast between the pale, blue-grey colour of the third, and highest, Lias precipice and the deeper shade of the underlying Black Marl. These pale marls, about 75 feet thick, soon pass off the eastern shoulder of Black Ven, but are readily picked up again as the eye follows the line of stratification eastwards, and across the valley, to Stonebarrow Cliff. There the pale marls make the second precipice, but soon dip to the beach to form most of the long, low cliff reaching from Westhay to the Ridge fault. These 75 feet of the pale marls are the Belemnite Beds of Day and of the Geological Survey. No adequate mention of them is made before 1863, when Day wrote his classic account of the Middle and Upper Lias of the Dorset Coast. although they are included in the ‘Upper Lias Marls’ of De la Beches earlier account, and form the middle part of the eighth bed from the bottom of the section there described. In De la Beches later account they occupy the middle of the lower part of his bed ‘a’: ‘Marls and slaty marls with several beds of indurated marl and earthy limestone in the lower part, micaceous in the higher—350 ft.’ In both accounts De la Beche particularly notes that belemnites are numerous, and other fossils occur in ‘marls on the shore, between

Cyathophyllum Cæspitosum Goldfuss, and other Devonian Corals considered in a Revision of that Species

I. Introduction Few names appear more frequently in the literature of Devonian palaeontology than “Cyathophyllum cæspitosum Goldfuss”; yet the descriptions of that species are most unsatisfactory, partly because a lectotype had not been chosen until lately (Lang and Smith, 1934, p. 80), and partly because the internal characters of the type specimens have not yet been made known. Occurring in a faunal list, the name usually connotes no more than a phaceloid coral. Goldfuss described the coral in 1826, on page 60 of his classical work “Petrefacta Germanise”, and illustrated it by figures of four syntypes, from the Eifel and Bensberg, in pl. xix, figs. 2 a–d. He also described and figured, in the same work, Lithodendron coespitosum (p. 44, pl. xiii, fig. 4), which has been considered by many authors a synonym of Cyathophyllum cæspitosum; and Cyathophyllum hexagonum (p. 61, pi. xix, figs. 5 a–f; pl. xx, figs. 1 a, b), of which the examples illustrated on pl. xix, figs. 5 a–d, have also been cited as conspecific with C. cæspitosum. Through the courtesy of Professor Tilmann, who has very kindly lent us the types (preserved in Bonn University), we have been able to investigate the structures of these species, and to choose a lectotype of Cyathophyllum cæspitosum: namely, the specimen figured in Goldfuss, 1826, p. 60, pl. xix, fig. 2 b. Since Cyathophyllum cæspitosum and Lithodendron cæspitosum cannot be included in either Cyathophyllum or Lithodendron, we have investigated the genotypes of the various genera to which those two

A Critical Revision of the Rugose Corals described by W. Lonsdale in Murchison's ‘Silurian System’

W. Lonsdale, in R. I. Murchisons ‘Silurian System’, 1839, pp. 675–94, pis. xv, xv bis, xvi, & xvi bis, described and figured a number of Silurian corals and polyzoa. In view of the prominence of this work in the literature of Palæozoic corals and polyzoa, and the importance to nomenclature of a right interpretation of many of Lonsdales figured forms, it is desirable that whenever possible the types and figured specimens should be re-examined and their internal structure carefully investigated. It should be noted that our paper deals solely with the Rugose corals. The genotypes of several genera are involved, as well as the types of a number of species. Many of Lonsdales forms have been misinterpreted by later authors, and placed by them in the synonymies of totally different coral-species. Our paper has issued as a by-product of a work of wider scope begun in 1923—namely, an investigation of all the genera to which Palæozoic corals have been referred, with a view to determining their genotypes; it is also auxiliary to our impending publication dealing with the Silurian corals described in Linnæuss ‘Corallia Baltica’ and with the genera and species involved in a consideration of these. It aims at identifying unmistakably Lonsdales Rugose coral-species, describing in detail those which do not come within the scope of our other work, and only very briefly considering such as will be fully described in that work. It has, however, been found desirable to consider also several of McCoys types, as well as

The Green Ammonite Beds of the Dorset Lias

I. Introduction. The Green Ammonite Beds comprise those horizons of the Dorsetshire Lias which lie above the Belemnite Stone—horizon of Beaniceras—and below the Three Tiers—nearly the lowest limit of Amaltheus. They bear this connotation in the memoirs of the Geological Survey, and include a greater thickness than was intended by Day (1863, p. 291), who first coined the term for 18 feet of clays lying in the lower part of the series as here defined, and yielding nodules in which the typical green ammonites are to be found. The chambers of these ammonites are often filled with greenish calcite—hence the vernacular name. The Green Ammonite Beds form part of the Upper Lias Marls of De la Beches earlier account (1826), and the middle part of the “marls and slaty marls with several beds of indurated marl and earthy limestone in the lower part, micaceous in the higher—350 ft.” of his later account (1839, p. 223). They are the equivalent of Oppels “Davöi-bett”, or “zone des Amm. Davöi” (Oppel, 1856–8, pp. 117, 126–9, 148, 151) and he records their occurrence on the Dorset coast (p. 129) as follows: “An der Küste von Charmouth bei Lyme Regis (Dorsetshire) fand ich dagegen nicht allein ein grosses und deutliches Exemplar von Amm. Davöi [also recorded on p. 161], sondern in seiner Begleitung auch die in Schwaben mit ihm zusammenliegenden characteristischen Arten: Amm. capricornus, Henleyi [also recorded on p. 164], Belemnites umbilicatus [also recorded on p. 154], elongatus [also recorded on p. 152], clavatus [also

Fletcherina , A New Name for a Palaeozoic Coral Genus

The name Fletcherina is proposed to replace Yabeia (preoccupied as a trilobite genus) and Cylindrophyllum. Like Fletcheria, to which it is allied, Fletcherina is placed in the rugose corals.

Naos pagoda (Salter), the Type of a New Genus of Silurian Corals.

I.—In 1873, J. W. Salter described a new species of Rugose Coral as follows:— ‘The genus [Ptychophyllum] is not confined to Britain. An Arctic form from the northern expeditions is in the cabinet o the Geol. Survey. In this the successive growths of the calyx are so regular and the limb turned so much back, that the whole resembles a Chinese pagoda, whence the name Ptychophyllum pagoda Salter.’ Salters description and the specimens which he has described appear to have remained unnoticed. R. S. Bassler has overlooked the species in his ‘Bibliographic Index of American Ordovician & Silurian Fossils’; nor can I find any reference to it in other literature. There are, however, in the British Museum (Natural History) three specimens of the G. H. Morton collection, labelled ‘Ptychophyllum pagoda, Salter, Niagara Group, Melville Island’ (Brit. Mus. R 4805-806, R 25163), and three specimens clearly of the same species (Brit. Mus. R 4983, R 25165-66), labelled ‘? Niagara Group, ? Disaster Bay, Arctic America’. It is nearly certain that the last were handed over by the Geological Survey to the British Museum in 1880, with other fossils from Arctic America, and that they are Salters syntypes. It is desirable, therefore, that Salters Ptychophyllum pagoda should be figured and described in detail. The specimens are silicified, and externally coated with beekite. Internally, the structure is beautifully preserved, and shows relationship both with Chonophyllum and Ptychophyllum. Diagnosis.—Simple Rugose corals with the outer part of the calice reflexed, and differing from Ptychophyllum in

Crataniophyllum, A New Name for a Carboniferous Coral Genus

Barbouria, proposed in 1940 for Creterophyllum Barbour, is now known to be preoccupied, and the name Crataniophyllum is proposed as a replacement.

The Kelestominæ: a Subfamily of Cretaceous Cribrimorph Polyzoa

I. Introduction. In 1906, under the name Cribrilina jukes-brownei, Mr. Brydone1 described a Cretaceous cribrimorph Polyzoan of remarkable structure. There is little beyond its cribrimorph intraterminal frontwall to connect it with Cribrilina;2 indeed, at the time of the establishment of C. jukes-brownei its affinities were unknown for lack of correct interpretation of certain of its more specialized features; and, were it not for the subsequent discovery of an allied species, Morphasmopora brydonei,3 connecting the highly-specialized M. [Cribrilina] jukes-brownei with a less-specialized form from Rügen described by Marsson under the name of Kelestoma elongatum,4 the extraordinary modifications of Morphasmopora jukes-brownei might still be unexplained. Kelestoma and Morphasmopora are quite separate, though allied, genera of Pelmatoporidæ, isolated from the rest of the family and constituting the subfamily Kelestominæ. The Pelmatoporidæ are a very large assemblage of Cretaceous cribrimorph Polyzoa, that is, of Cheilostome Polyzoa whose intraterminal front-wall is built of more or less fused terminal spines. The family consists of those whose fused spines (costæ) are produced as hollow outgrowths upwards beyond their fusions; the broken ends of these form rows of pelmata (when of small diameter, pelmatidia) on the surface of the intraterminal front-wall. The complete family was dealt with in summary detail in 1916,5 and its largest section, the subfamily Pelmatoporinæ, in a more expanded manner in [1919].6 Its various subfamilies may be derived from a hypothetical ancestral Pelmatoporid, and, in order to explain the structure and evolution of the Kelestominæ, it is convenient first to examine this hypothetical Pelmatoporid