Bulletin of the United States Geological SurveyThe Survey., 1909 |
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Algonkian Animikie anorthosite Archean argillite associated Azoic bands basal beds belt Cambrian chloritic clastic conglomerate consists copper-bearing correlation County crystalline limestone crystalline rocks deposits describes diabase dikes diorite district dolomite eastern eruptive feet felsite folded fossils fragments gabbro Geol geologists geology gneiss gneissic granite granites and gneisses graywacke green schists greenstone Hise horizontal hornblende Huronian Huronian rocks Huronian series Idem igneous rocks interstratified intrusive iron formation iron-bearing jasper Keewatin Keweenawan Lake Superior Lake Superior region later Laurentian lavas limestone lithological Lower Huronian Marquette masses Menominee Mesabi metamorphic metamorphosed mica schists mica slate micaceous miles Minnesota Mountain occur origin overlying Paleozoic pebbles Penokee places porphyry Potsdam pre-Cambrian pre-Cambrian rocks quartz quartzite range Rept River sandstone schistose schists sedimentary rocks sediments shales shore siliceous Silurian strata stratified structure syenite Taconic thickness tion trap unconformably Upper Huronian Vermilion volcanic WINCHELL Wisconsin
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Seite 647 - A geological and agricultural survey of the district adjoining the Erie canal in the state of New York.
Seite 293 - It is notable as containing the intrusive sills called by Lawson the Logan sills. At one place near Loon Lake a test pit has been sunk to the bottom of the Animikie, and here at the base of the formation is a conglomerate bearing fragments of the next underlying series — a graywacke slate.
Seite 399 - Report on the geology of the area covered by the Seine River and Lake Shebandowan map sheets, comprising portions of Rainy River and Thunder Bay districts, Ontario.
Seite 452 - ... is patiently and continuously to follow the outcrop of each important mass in all its windings, as far as it can be traced, until it becomes covered up by superior unconformable formations, is cut off by some great dislocation, or disappears by thinning away to nothing.
Seite 682 - ... however, resemble each other much more than they do any of the members of the other formations. The Cranberry granite is a series of light colored acid gneisses and the Roan gneiss a series of dark colored basic gneisses. ROAN GNEISS The Roan gneiss, according to Keith, "consists of a great series of beds of hornblende gneiss, hornblende schist, and diorite with some interbedded mica schist and mica gneiss. The hornblendic beds are dark greenish or black in color, and the micaceous beds are dark...
Seite 106 - The origin of the oldest fossils and the discovery of the bottom of the ocean, by WK Brooks.
Seite 294 - ... Shoal Lake conglomerate. This conglomerate lies upon an area of green schists and granites known as the Bad Vermilion granites. It holds numerous large well-rolled fragments of the underlying rocks, and forms the base of a sedimentary series. It is certain that in this line of section the Couchiching is stratigraphically higher than the chloritic schists and conglomerates mapped as Keewatin. On the south side of Rat Root Bay there is also a great conglomerate belt, the dominant fragments of which...
Seite 123 - At several points dioritic schists, semi-amygdaloidal in character, were observed, and in one instance the rock had a strong resemblance to conglomerate. The bedding of the rocks is generally obscure, and sometimes entirely wanting. It is only by a full study of the rock in mass and its relations to the adjacent beds that one becomes convinced, whatever its origin, that it presents in mass precisely the same phenomenon as regards stratification as do the accompanying schists and quartzites.
Seite 405 - Huronian; the rocks of the latter are more recent and have been observed to pass nnconformably below the lowest of the fossiliferous strata of the Silurian system. The contorted gneiss of the Laurentian series, with its associated micaceous and hornblendic schists, spreads over the country to the south and east, while the slates, conglomerates, limestones, quartzites, and greenstones of the Huronian occupy the northern and western parts. The difference in lithological character between the two formations...
Seite 594 - Remarks on the Geology and Mineralogy of a section of Massachusetts on Connecticut River, with a part of New Hampshire and Vermont.