wm IMAGE EVALUATION TEST TARGET (MT-S) J/. m^ A ^ ^d ^ 1.0 ■JO ""^^ UIH^^ :^ ]^ 11112.0 — ^^— I.I ...LiL. III =-8 1.4 1.6 1.25 1 1 /I p^ // '>> ^^ signifie "A SUIVRE", le symbols V signifie "FIN". Maps, plates, charts, etc., may be filmed at different reduction ratios. Those too large to be entirely included in one exposure are filmed beginning in the upper left hand corner, left to right and top to bottom, as many frames es required. The following diagrams illustrate the method: Les cartes, planches, tableaux, etc., peuvent ^tre filmis d des taux de reduction diff6rents. Lorsque le document est trop grand pour dtre reprodjit en un seul clich6, ii est filmd A partir de I'angle sup6rieur gauche, de gauche d droite, et de haut en bas, en prenant le nombre d'images ndcessaire. Les diagrammes suivants illustrent la m^thode. 1 2 3 5 6 [Reprinted from the Canadian Record op Soibnob, January, 1889J •■,■-:, ' On Modern Concretions from the St. Lawrence. (/| | > By Rev/Pkop. Kavanagh, S. J. V^iTH Eemarks on Cylinders found in the Potsdam Sand?.tone. The modern concretions referred to were collected on the the rush-covered shores of the St. Lawrence near Boucher- ville, and may be thus described : — They resemble small radishes, like these, varying much in shape, are symmetrical, perforated axially, the more or less perfect bore or perforation often containing vegetable fibres. Their production seems to be due to the action of the rush roots upon the soft, plastic clcy, so indurating it that it can resist the wash of the waves ; the receding of the water during the summer leaves these concretions standing out in relief, like fossils on a weathered surface. \ t ■■h ii ■•■■ ♦ '■■ m^mwrnmrnmimmm »• a • • • • • > • ••• ' *. ■. » * ,» .— , .1 ■/ Modern CQmretipnsfrom th^ St Lawrence. 293 The phenomenon seems to be analogous to that formation of nodules around organic nuclei within masses of soft mate- rial, which occurs in many geological formations. These little bodies ai'e evidently clay concretions formed around vegetable fibres, and hardened by a small percentage of calcium carbonate . since when treated with hydrochloric acid they effervesce feebly and become disintegrated. They probably orig\nate in the molecular aggregation of the cal- careous matter in the clay around any foreign body in- cluded in it. They are about half an inch in diameter, and the largest may have been two inches in length, with rounded ends. When broken, they show a s^mall central canal con- taining a little sand and strips of epidermal tissue, the re- mains _!' a root or stem. One shows three branches appa- rently proceeding in a verticillate manner from a central stem. In the centre, the light, reddish-brown colour of the clay has assumed a greenish hue, owing to deoxidation of the Peroxide of Iron by decay of the vegetable nucleus. Ekmarks by the President on Certain Ancient Concre- tions, IN Connection with the Above. On a small scale these modern concretions are similar to those so often found to enclose vegetable remains in Ihe carboniferous system ; and in the Pleistocene at Green's Creek, on the Ottawa, vegetable stems are sometimes found enclosed in similar, but larger and harder concretions. Concretions of this kind appear to throw light on those remarkable trunk-like cylinders which have been found in the Potsdam sandstone. These attracted the attention of Sir Wm. Logan many years ago ; but as they showed no struc- ture, external markings, or carbonaceous matter, they were not regarded by him as true fossils. Moi j recently they have been studied by Dr. Selwyn in exposures on the bank of the Eideau canal, near Kingston. Dr. Selwyn has kindly sent photographs of these specimens, to be exhibited to the Society. Mr. A. Young, a student in applied science in McGill University, has also presented fine specimens to the Sr'JIggi^LWLWJLjualfciMI ^mi^ ■i«IKH 294 Canadian Record of Sdff^ce. Peter Eedpath Museum, one of which is on the table. In their entirely arenaceous character, their concentric lines of growth, as well as in traces of a central ax,s orcana^^of Lai. dimensions, and, in one instance, '» * -f "^ rounded end, they resemble concretions, Dut I have been ™1 to And any central organic matter. ™s may^^ow^ ever have perished, leaving a mere cavity as in *« ""dern crcretions'above describ«i, which would "e-me .M w «>_ sand like that of the enclosing cyl.ndor. This at least ap warstome at present the most probable explanation o CL r«^ing forms. It would be conttrmed if any distinct trtSe or zophytic axis could be found in any of the ZcCns or any carbonaceous matter representing such ir^Ts V the meantime, it may be regarfed as a more or less probable conjecture as to their origin. ; — ■