Crinoid Fragments Research Articles

Les echinodermes permiens du Djebel Tebaga (extreme sud tunisien)

Abstract Describes echinoderms from Permian deposits of the Tebaga massif in southernmost Tunisia. These include stem and calyx fragments of crinoids and isolated plates and radioles of the echinid genus Archaeocidaris.

Uintacrinus Localities in the Niobrara Formation of Kansas

The free-swimming crinoid Uintacrinus Grinnell (1876) has been found in the upper Cretaceous rocks of England, Germany, and the Western Interior region of North America. Grinnell's (1876, p. 81) description was based on specimens from the Uinta Mountains of Utah and the Cretaceous of Kansas. The European example, Uintacrinus westphalicus Schluter (1878), (Zittel, 1913, p. 236) occurs with Marsupites and Bourgeticrinus. Neither Marsupites nor Bourgeticrinus has been found with Uintacrinus in Kansas. In Kansas, Uintacrinus socialis Grinnell normally occurs in great abundance in small areas. Some slabs of approximately 35 square feet have as many as 250 complete individuals represented. Logan (1898, p. 483) described two Uintacrinus slabs, one of which exhibits specimens of adult size; the other has specimens of one-fourth that size and a few near-adult size specimens. The juvenile specimens on the slab mentioned by Logan measure 14 to 35 mm. in diameter. In the fall of 1956 the senior author discovered a small crinoid slab on which the smallest individual measured 35 mm. and the largest measured 65 mm. in diameter. The diameters of the other calices formed a gradation between the two extremes, but most of them measured 55 mm. or larger. The limestone beds containing the crinoid calices are a coquina of crinoid fragments, and usually the slab is one-quarter to one inch thick. The complete calices are on the underside of the slabs when they are in place in the Niobrara formation, and fragments form the remainder of the slabs.

XIX. On Carboniferous Crinoids from Fyfe, with notes on some localities and provisional lists of species

Introduction. Viewing a section of one of the Lower Carboniferous Limestones, and noting the prodigious numbers of crinoid fragments of which it is usually composed, one cannot but regret that so very few complete specimens of the organisms have been preserved to us. This has always been a subject of lament to Scottish palæontologists. In the Carboniferous Limestones of Scotland, as a whole, cups even appear to be of rare occurrence, and judging from the lists of species hitherto published, and the specimens exhibited in our museums, they occur at widely-separated localities. Now, in Fife this is not the case, where, I am glad to say, it has been my good fortune to find several localities within a short distance of one another, where large numbers of cups and more or less entire specimens may be found. This is an interesting fact, for among the many classes of organisms which abound in our rocks there is, I think, no more beautiful object than a well-preserved crinoid—a specimen which always brings a thrill of joy and delight to the heart of its discoverer. If we examine the collections of Scottish Carboniferous fossils which are exhibited in our museums, the crinoids occupy but a small space compared with other classes. Further, if we note the lists of crinoid species from Scotland recorded in various publications, the total is by no means large. Scottish Carboniferous crinoid nomenclature is in a very unsatisfactory state at present, and when we remember that many of the This 250-word extract was created in the absence of an abstract

Hydrous Silicates Injecting the Pores of Fossils

DR. T. STERRY HUNT directed attention some time ago* to a remarkable limestone of Silurian age from Pole Hill, New Brunswick, in which I had found the cavities of fossil crinoids to be filled with a siliceous substance perfectly injecting their most delicate cellular structure, and which Dr. Hunt, on chemical analysis, found to be a hydrous silicate allied to jollyte. I have since, in examining with the microscope various specimens of limestone in the collection of McGill College, met with a British example of this kind of injection, to which I would wish to direct the attention of your microscopists. It is a specimen of olivaceous, imperfectly crystalline limestone, labelled Llangedoc, Wales. The only distinct fossil which it contains is a small body having the characters of the genus Verticillopora. It is filled, however, with crinoidal fragments and fragments of shells, and, when sliced, displays a few very minute univalves, probably of the genus Murchisonia, and also portions of a sponge-like organism with square meshes. The pores and cavities of many of these fossils are filled with a greenish or brownish finely crystalline silicate, which must have been introduced when the organic bodies were still recent, and which Dr. Hunt has ascertained to have the following composition:—