PROCEEDINGS OF GEOLOGICAL SOCIETIES. 



167 



copper, bornite, copper-glance, copper-pyrites, varieties of galena, zinc-blende, 

 magnetite, specular iron-ore, manganese -ore, orpinient, sulphm^, and brown-coal. 

 The series of copper-ores appears to indicate the existence of considerable masses 

 of metallic mineral, probably in lodes or regular veins. The lead-ores have the 

 appearance of hanng been taken either from veuis of small size, or from near the 

 surface of the gTOund. 

 The specimens alluded to were exhibited. 



2. " On the Yeins of Tin-ore at Evigtok, near Arksut, Greenland." By J. W. 

 Tayler, Esq., F.G.S. 



These tin-veins, of wliich there are about twenty, extend over an area of about 

 1,500 feet in length by 80 feet in breadth ; and they ran in various directions, 

 some E. and W., others N.E. and S.W., and others N. and S. They vary from 

 10 inches to I of an inch in width ; in the largest veins the tm-ore occupies about 

 1 inch of one side of the vein. The vems nearly all occur in a great vein of felspar 

 and quartz ; w^hich contains also ores of lead, copper, zinc, iron, and molybdena, 

 associated with ciyolite, fluor-spar, zircon, &c. 



Specimens from Evigiok were exhibited, from the Collections of Prof. Tennant, 

 F.G.S., and the Society. 



3. " On the Permian Chitonidse." By J. W. Kirkby, Esq. Communicated by 

 T. Davidson, Esq., P.R.S., F.G.S. 



After having fidly noticed the progTess of our knowledge respecting the palaeozoic 

 Chitons, and those of the Magnesian Limestone in particular, the author described 

 in detail the characters of Chiton Loftusianus, King, and Chiton Motvseaniis, Kirkby, 

 and a new species, referred with some doubt to Chiton C. (?) cordatus ; also Chiton 

 antiquus, Howse, which Mr. Kirkby refers to the subgenus ChitoneUus, as well as 

 two new species, C. HancocJcianus and C. distortus. The specimens on wliich all 

 these species have been determined have been found in the Magnesian Limestone 

 of the neighbourhood of Sunderland, Durham, and chiefly in that of Tunstall 

 Hill. 



The author particularly alluded to the great similarity that some of the plates 

 of these fossil Chitons have at first sight to Patellce and Calyptvcecs, and recom- 

 mended that especial care should therefore always be taken in the determination 

 of patelhform fossils. 



The paper was illustrated by fine pencil-drawings by the author. 



4. " On the Vegetable Structures in Coal." By J. W. Dawson, LL.D., F.G.S., 

 Principal of M'Gill College, Montreal. 



After referring to the labours of others in the elucidation of the history of coal, 

 the author remarl^s that in ordinary bituminous coal we recognise by the unaided 

 eye laminae of a compact and more or less lustrous appearance, separated by un- 

 even films and layers of fibrous anthracite or mineral charcoal. As these two 

 kinds of material difter to some extent in origin and state of preservation, and in 

 the methods of study applicable to them, he proceeds to treat of his subject under 

 two heads :— 1st. The structures preserved in the state of mineral charcoal. This 

 substance consists of fi-agments of prosenchymatous and vasiform tissues in a car- 

 bonized state, somewhat flattened by pressure, and more or less impregnated with 

 bituminous and mineral matters derived from the surrounding mass. It has 

 resulted from the sub aerial decay of vegetable matter ; whilst the compact coal 

 is the product of subaqueous putrefaction, modified by heat and exposure to air. 

 The author proceeded (after describing the methods used by him in examining 

 mineral charcoal and coal) to describe the tissues of Cryptogamous plants in the 

 state of mineral charcoal. Among these he mentions Lepidodendron and Uloden- 

 dron, also disintegrated vascular bundles from the petioles of Ferns, the veins of 

 Stigmarian leaves, and from some roots or stipes. He then describes tissues of 

 Gymnospermous plants in the state of mineral charcoal ; especially wood with 

 discigerous fibres and also with scalariform tissue, such as that of Stigmaria and 

 Calamodendron ; and the author remarks that probably tiie so-called cycadeous 

 tissue liitherto met with in the coal has belonged to Sigillarice. 



The next chief heading of the paper has reference to structures preserved in the 

 layers of compact coal, wliich constitute a far larger proportion of the mass than 

 the mineral charcoal does. The laminae of pitch- or cherry-coal, says Dr. Dawson, 



