Bulletin of the Geological Society of America

Vols. for 1938-61 include as pt. 2 of the December issue the Society's Abstracts, later published separately.

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Seite 192 - ... the tunnel, or of between 200 and 300 feet beyond the edge of the solid lava, Mr Neale saw several spear-heads, of some dark rock and nearly one foot in length. On exploring further, he himself found a small mortar three or four inches in diameter and of irregular shape. This was discovered within a foot or two of the spear-heads. He then found a large, well-formed pestle...
Seite 285 - The stratigraphical importance of the coal seams is not so great as has been generally supposed, since the bituminous beds are, with very few exceptions, quite limited. Only a single case is at present known in which the geographic extent of a coal stratum is more than four or five miles, and for the greater part of this distance the coal is but a few inches in thickness. It follows that the coal seams of the region are not nearly so extensive as commonly supposed, and that they possess little value...
Seite 593 - ... 37. White coarse conglomerate, the matrix material being calcareous. The quartzose pebbles decrease in size toward the top, and the stratum becomes more argillaceous. There are many casts, but all too obscure for identification _ 18 38.
Seite 601 - Alabama 30 17 — Gray, highly fossiliferous marl. The fossils are nearly, if not quite, all bivalves, and are mostly comminuted as if they formed an ancient shoreline. There are numerous shark teeth and a hard black substance resembling in sections the under shell of a turtle, black coprolitic (?) pebbles, and fragments of lignite 3...
Seite 114 - The rocks on the Lake of the Woods, which are in the following pages referred to as agglomerate schists, are not basal conglomerates. They are not at the base of the series included in the schistose belt, nor are they apparently composed of water-worn fragments, derived from the rocks upon which they rest. "No fragments that can be referred to the underlying granitoid gneisses are found included in the agglomerate schists of the Lake of the Woods.
Seite 97 - ... were accidentally inclosed. From this it is evident that the slate conglomerate was not deposited until the subjacent formation had been converted into gneiss, and very probably greatly disturbed ; for while the dip of the gneiss, up to the immediate vicinity of the slate conglomerate, was usually at high angles, that of the latter did not exceed nine degrees, and the sandstone above it was nearly horizontal.
Seite 91 - The pebbles and bowlders of metamorphic rocks which abound in the gravel and clay deposits, and are numerously scattered over the surface, are clearly derived from the Laurentian and Huronian formations on the north shore of Lake Huron
Seite 95 - ... certain; and the conclusive evidence given of the age of the Huron, would thus appear to settle that of the Lake Superior rocks, in the position given to them by Dr. Houghton, the late State Geologist of Michigan, as beneath the lowest known fossiliferous deposits...
Seite 107 - ... it appears to me, must be taken as belonging to one formation ; on the west it seems to repose on the granite which was represented in my report on Lake Superior as running to the east of Gros Cap, north of Sault Ste. Marie ; on the east the same supporting granite was observed by Mr. Murray, north of La Cloche, between three and four miles in a straight line up the Riviere...
Seite 292 - ... as is shown in the deep gorges and ravines which are still preserved in the hard sandstone. So widespread and intense was the action of the erosive agencies that the great sandstone, more than one hundred and fifty feet in thickness, was largely removed; and at the present day only a few isolated outliers tell of its former great extent. When regional submergence again set in, the old gorges and shore depressions were occupied by coal swamps.

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