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Prince Edward Island possesses excellent sandstone for building, abundance of brick clay, and large deposits of valuable peat. The Coal Formation rocks underlie the whole of the Island, but are probably at a depth too great to permit their profitable exploration at present. Iron, copper, and manganese ores in small quantities occur, but are insufficient for mining purposes. There are beds of useful though impure limestone. Fossil plants, as trunks of coniferous trees and leaves of ferns, occur in great abundance in the beds of the Upper Coal formation, and a few fossil plants occur in the Trias, among them a stem of a cycad, the first discovered in these Provinces. The most remarkable fossil of the latter formation is the large and formidable reptile Bathygnathus borealis, an ancient inhabitant of Prince Edward Island, comparable with the great Saurians, which have left their remains in rocks of similar age in the old world. The boulder formation occurs in Prince Edward Island, and in its upper portion includes boulders which must have been drifted from Labrador on the one hand and New Brunswick on the other. Another very remarkable feature of the modern geology is the great extent of sand dunes or hills of blown sand, along the northern coast. For further details the author referred to a report recently prepared by himself and Dr. Harrington, on the geology of this ineres ting and important Province.
After the reading of this paper, Dr. T. Sterry Hunt made some commendatory remarks on its general scope and scientific. aspect, and pointed out that in this Island we have an example of two rock formations resting conformably the one on the other, between which a "lost epoch" (the Permian formation) should have intervened, if the succession of rocks had been unbroken. Dr. B. J. Harrington also gave an account of the peat formations of the Island.
Mr. E. Billings read a paper "On some supposed fossils from the Huronian Rocks of Newfoundland."
These supposed organisms, as they are provisionally regarded, belong to two species, or at any rate present two kinds of appearances, but their affinities are at present exceedingly doubtful. A discussion ensued as to the age of the rocks in which these supposed fossils were found, Mr. Billings maintaining (with Mr. A. Murray, the Director of the Geological Survey of Newfoundland), that they are of Huronian age, and Dr. T. Sterry Hunt, that they are of a newer horizon, and belong to the base of the Primordial zone.
4th Monthly Meeting, Feb. 26th, 1872.
Prof. H. A. Nicholson, of Toronto, was elected a corresponding member of the Society.
A paper by Prof. H. A. Nicholson, entitled Sexual Selection in Man, was presented, and Mr. Darwin's views on that subject, with Prof. Nicholson's comments thereon, were explained and illustrated by Principal Dawson. Prof. Nicholson's paper will appear in the next No. of this journal.
A paper entitled "On the Cultivation of Chenopodium Quinoa," was read by Principal Dawson. This we hope to print also in our next number.
Dr. P. P. Carpenter made a communication "On the present condition and causes of the Montreal Death Rate."
The six Annual Lectures of the Somerville Course were duly delivered as follows:
1. Feb. 8th, 1872.-On Mont Blanc, by Dr. T. Sterry Hunt, F.R.S.
2. Feb. 15th, 1872.-A New England Clam-Bake, by Dr. P. P. Carpenter.
3. Feb. 22nd, 1872.-Applied science as illustrated in the processes of Chromo and Photo-Lithography, by Prof. J. B. Edwards, Ph. D., D.C.L., &c.
4. March 7th, 1872.-The elementary principles of Spectrum Analysis, by Prof. G. F. Armstrong, M.A., F.G.S.
5. March 14th, 1872.-On Thermometers and other measures of Heat, by Dr. G. P. Girdwood.
6. March 21st, 1872.-On Fossil Foot-prints, by Principal Dawson, LL.D., F.R.S., &c.
GEOLOGY AND MINERALOGY.
ON THE STRUCTURE OF THE PALEOZOIC CRINOIDS.-The best known living representatives of the Echinoderm class Crinoidea are the genera Antedon and Pentacrinus—the former the feather stars, tolerably common in all seas; the latter the stalked sea-lilies, whose only ascertained habitat, until lately, was the deeper portion of the sea of the Antilles, whence they were rarely recovered by being accidentally entangled on fishing-lines. With . in the last few years Mr. Robert Damon, the well-known dealer in natural history objects in Weymouth, has procured a considerable number of specimens of the two West Indian Pentacrini, and Dr. Carpenter and the author had an opportunity of making very detailed observations both on the hard and the soft parts. These observations will shortly be published.
The genera Antedon and Pentacrinus resemble one another in all essential particulars of internal structure. The great distinction between them is, that while Antedon swims freely in the water, and anchors itself at will by means of a set of "dorsal cirri," Pentacrinus is attached to a jointed stem, which is either permanently fixed to some foreign body, or, as in the case of a fine species procured off the coast of Portugal during the cruise of the Porcupine in the summer of 1870, loosely rooted by a whorl of terminal cirri in soft mud. Setting aside the stalk, in Antedon and Pentacrinus the body consists of a rounded central disc and ten or more pinnated arms. A ciliated groove runs along the "oral" or "ventral" surface of the pinnules and arms, and these tributary brachial grooves gradually coalescing, terminate in five radial grooves, which end in an oral opening, usually subcentral, sometimes very excentric. The oesophagus, stomach, and intestine coil round a central axis, formed of dense connective tissue, apparently continuous with the stroma of the ovary, and of involutions of the perivisceral membrane; and the intestine ends in an anal tube, which opens excentrically in one of the inter-radial spaces, and usually projects considerably above the surface of the disc. The contents of the stomach are found uniformly to consist of a pulp composed of particles of organic matter, the shields of diatoms, and the shells of minute foraminifera. The mode of
nutrition may be readily observed in Antedon, which will live for months in a tank. The animal rests attached by its dorsal cirri, with its arms expanded like the petals of a full-blown flower. A current of sea water, bearing organic particles, is carried by the cilia along the brachial grooves into the mouth, the water is exhausted of its assimilable matter in the alimentary canal, and is finally ejected at the anal orifice. The length and direction of the anal tube prevent the exhausted water and the focal matter from returning at once into the ciliated passages.
In the probably extinct family Cyathocrinidae, and notably in the genus Cyathocrinus, which the author took as the type of the Palæozoic group, the so-called Crinoidea Tessellata, the arrangement, up to a certain point, is much the same. There is a widelyexpanded crown of branching arms, deeply grooved, which doubtless performed the same functions as the grooved arms of Pentacrinus; but the grooves stop short at the edge of the disc, and there is no central opening, the only visible apertures being a tube, sometimes of extreme length, rising from the surface of the disc in one of the inter-radial spaces, which is usually greatly enlarged for its accommodation by the intercalation of additional perisomatic plates, and a small tunnel-like opening through the perisom of the edge of the disc opposite the base of each of the arms, in continuation of the groove of the arm. The functions of these openings, and the mode of nutrition of the crinoid having this structure, have been the subject of much controversy.
The author had lately had an opportunity of examining some very remarkable specimens of Cyathocrinus arthriticus, procured by Mr. Charles Ketley from the Upper Silurians of Wenlock, and a number of wonderfully perfect examples of species of the genera Actinocrinus, Platycrinus, and others, for which he was indebted to the liberality of Mr. Charles Wachsmuth, of Burlington, Ohio, and Mr. Sydney Lyon, of Jeffersonville, Indiana; and he had also had the advantage of studying photographs of plates, showing the internal structure of fossil crinoids, about to be published by Messrs. Meek and Worthen, State Geologists for Illinois. A careful examination of all these, taken in connection with the description by Prof. Lovén, of Hyponome Sarcii, a recent crinoid lately procured from Torres Strait, had led him to the following general conclusions.
In accordance with the views of Dr. Schultze, Dr. Lütken, and Messrs. Meek and Worthen, he regarded the proboscis of the
tesselated crinoids as the anal tube, corresponding in every respect with the anal tube in Antedon and Pentacrinus, and he maintained the opinion which he formerly published (Edin. New Phil. Jour. Jan. 1861), that the valvular "pyramid" of the Cystideans is also the anus. The true mouth in the tesselated crinoids is an internal opening vaulted over by the plates of perisom, and situated in the axis of the radial system more or less in advance of the anal tube, in the position assigned by Mr. Billings to his "ambulacral opening." Five, ten, or more openings round the edge of the disc lead into channels continuous with the grooves in the ventral surface of the arms, either covered over like the mouth by perisomatic plates, the inner surface of which they more or less impress, and supported beneath by chains of ossicles; or, in rare cases (Amphoracrinus), tunnelled in the substance of the greatly thickened walls of the vault. These internal passages, usually reduced in number to five by uniting with one another, pass into the internal mouth, into which they doubtless lead the current from the ciliated brachial grooves.
In connection with different species of Platyceras with various crinoids, over whose anal openings they fix themselves, moulding the edges of their shells to the form of shell of the crinoid, is a case of commensualism," in which the mollusc takes advantage for nutrition and respiration of the current passing through the alimentary canal of the echinoderm. Hyponome Sarsii appears, from Prof. Lovén's description, to be a true crinoid, closely allied to Antedon, and does not seem in any way to resemble the Cystideans. It has, however, precisely the same arrangement as to its internal radial vessels and mouth which we find in the older crinoids. It bears the same structural relation to Antedon which Extracrinus bears to Penta crinus.
Some examples of different tesselated crinoids from the Burlington limestone, most of them procured by Mr. Wachsmuth, and described by Messrs. Meek and Worthen, show a very remarkable convoluted plate, somewhat in form like the shell of a Scaphander, placed vertically in the centre of the cup, in the position occupied by the fibrous axis or columella in Pentacrinus and Antedon. Mr. Billings, the distinguished palæontologist to the Survey of Canada, in a very valuable paper on the structure of the Crinoidea, Cystidea, and Blastoidea (Silliman's Journal, January, 1870), advocates the view that the plate is connected with the apparatus of respiration, and that it is homologous with