On the Permian Chitonidæ

Abstract

XlRKBY-P~RMIAZ~ C~IX0Z~IDZ:. 607 those veins is 10 inches,-the tin being 1 or 1~ inch, occupying one side of the vein. The gangue here is felspar, quartz, sparry iron (carbonate of iron ?), and fluor-spar. This vein runs E. and W., into the white cryolite. Another vein, about 200 feet west from the cryelite, is visible for about thirty paces ; at the surface it is not more than ~ of an inch thick, but at a depth of 6 feet it is 3 inches thick. Other veins are, at the surface, mere strings, varying from to ~ of an inch thick. Nearly all these veins occur in a large vein or bed of felspar and quartz, some of the crystals of the latter having a diameter of 18 inches. This mass contains, in a limited space, various other minerals, such as galena, blende, copper-, iron-, and arsenical-pyrites, fluor-spar, black cryolite, tantalite, molybdena, sparry iron, zLrcon, &c. There are some peculiarities connected with these tin-veins, which deserve consideration, and would lead one to expect that at a greater depth they might afford a large produce. The only surfacevein which can be seen sectionally (no sinkings having yet been made) widens rapidly as it descends; and in other spots sectional views of two small veins are to be seen, which do not reach the surface. The most remarkable of these is a vein which I found in the floor of a smaU cavern : it consisted at first of sparry iron, arsenical pyrites, fluor, &c. ; a few feet deeper it changed its character, and contained good traces of copper ; but water prevented us following it deeper; it is here about 15 inches wide. The minerals accompanying the copper are those usually met with in good and productive veins, besides the black cryolite, which is here peculiar to it. These veins, in my opinion, evidently belong to the underlying granite, which appears at the surface in veins, and which is probably at no great depth below, since the tin-veLr~s penetrdte into the overlying gneiss, which dips to the south, and under the outcrop of it the granite loses itself. It is highly probable that the cryolite forms a bed between the gneiss and granite, but partly enclosed in the gneiss. We have not yet, however, seen the bottom of the cryolite in any of our workings. This tin-district differs from all others known, being associated with the cryolite, whilst tantalite seems to have taken the place of wolfram, which generally accompanies tin-ores.

A new genus and two new species of multiplacophorans (Mollusca, Polyplacophora, Neoloricata), Mississippian (Chesterian), Indiana

“…The laminae ordinarily would not be observable in a fully articulated specimen or preserved in disarticulated valves due to rapid fracturing of the thin structures. Nonetheless, the illustration of an isolated tail valve of S. spinigera shows remnants of suturai laminae (Hoare and Mapes, 1995, fig. 3), and possible remains of similarly broken off suturai laminae are also discernible in figured Diadeloplax tails (Kirkby, 1859;Hoare and Mapes, 2000).…”

Marine Permian of England

“…The shelly rocks of Tunstall Hills have been known since the writings of Winch (1817) and Sedgwick (1829) and, together with those at Humbledon Hill, were the main collecting ground for Howse (1848Howse ( , 1858, King (1848King ( , 1850 and Kirkby (1857Kirkby ( , 1858Kirkby ( , 1859; few additional species have been found here since 1860, though long lists were given by Trechmann (1945), Logan (1967), Pattison (internal Geological Survey report, 1966) and Hollingworth (1987). Hollingworth also gave a faunal list from the 'Rock Cottage' exposure, where some of the gastropods have retained part or all of their original colour (Hollingworth, 1987;Hollingworth and Tucker, 1987;Hollingworth and Pettigrew, 1988).…”

“…Early references to the reef-rocks at Tunstall Hills are too imprecise for locations mentioned to be identified now, though it is possible that all the various exposures were grouped together for reporting purposes; if this were so, fossils from the south-eastern end of the hills could have been included in the fossil lists published by, for example, King (1848King ( , 1850, Howse (1850Howse ( , 1858 and Kirkby (1857Kirkby ( , 1858Kirkby ( , 1859. Analyses of reefrock by Trechmann (1914, p. 241) seem likely to be from the large quarry at this end of the hills, however, and brief comments on the reef-rock in this same quarry were made by Trechmann (1945, p. 344).…”

Permian Polyplacophora, Rostroconchia, and Problematica from Oregon

“…The problematic species Diadeloplax apiculatus n. sp. is most like that described from the Permian of England, D. antiquus (Howse), by Kirkby (1859). Study of additional Permian faunas from the Western Hemisphere may provide more insight into the paleobiogeographic usefulness of polyplacophorans, rostroconchs, and problematic taxa.…”