Eastport quadrangle notebook # 1, 1907
Page 23
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Transcription
In front of the Silurian shale originally described below extends along the level, serpentine rock continuous in the shale. This porphyry band with the shale here N. 70° west. If into across the shale but apparently does not cut across the granite gneissolite. The rhyolite (c) of the preceding section appears to cross the porphyry or at least deflection line. The porphyry there N.70° W. along the west portion of the slide (a). Following this direction with the rhyolite (C), the are run against the rhyolite; the band of porphyry is not however cut across by the rhyolite but is deflected, for it is found a few yards in front of the rhyolite band (c) and arrives around in an arched line in front of the shale (d) and terminates in the interval between the shales (d) and the rhyolite (B). It does not cut across also latter bit apparently ends against it. 1007. piece of porphyry in E. 1008. a rhyolite zone F. 1009. a porphyry from in front of rhyolite C. [illegible] Tuesday June 11 1897 Starting At the railroad bridge crossing from Moose Island to Fox Island and following the indentant shore of the portion of Moose Island southerly we come in contact first with the rhyolite F of page 330-34, and the successively lower beds in the geologic section, all of which are exposed on the first point extending S.W. and just west of the house shown on the map. In the little core there are no outcrops but on the rock ledge extending easterly on the north boundary of the face is completely rhyolite. This rhyolite is quite coarse grained like same as beds "B" and "F" (section on page 33), but in one place on the north side of the point, the rock is greener finer grained and indicates a contact probably with underlying shales. In the little core on the shore line between the two rock ledges near the center of Eastport 3.44.7c there are no outcrops, but the southward of these two ledges as composed of Silurian shales and interstratified volcanic dusts. These dusts are red in color are very fine grained & resemble red shales but are not definitely stratified. They present a fine net work structure in contrast with the coarser stratified sandy shale seams interstratified with them. These dust seams are not continuous, but pass into stratalings shales on either side, the red dust appearing as patches in the shales. The strike of these shales & dusts is N. 80° W., dip 27°, E.N. 5° E. There may be perhaps twenty feet of strata so kind point of which the lower half are wave and ripple marked. In the middle occurs a gray shale showing finely preserved anna-shrinkage-cracks filled in solid finer gray shale & also showing rain drop prints on the same surface. Slim together with the now marks & presence of fingalines indicates very shallow-water beaches or tidal flats. Fossils occur in both the gray shales & in the red dust beds. Lamellibranchs are common in the latter, [illegible] (morderpsis), bivalvata, lingulace rare. The lingulae are uncommon in the gray shales. Fossils 3.44.7c. These rocks are much preserved and pyrite crystals with some calcayte are abundant & not near the fissure a specimen with pyrite was collected No. 1011. At the south tip of this point, there occurs just covered at high water) a three feet layer of embedded red volcanic dust & which also appears in the tiny core 75 percent southerly. Have some red dust bed shews no lamination, but as usual is finely laminated with exhibiting fine reticulate structure. It is capped by a third with [illegible] plane ash. Some specimens of the volcanic ash are labelled "3.44.7e" and of the underlying dust beds 3.44.7c." (The dust is usually a deep purple red but no ground green in spots. Six specimens collected are greenish.) In the [illegible] (at high tide) just S.E. of the ash & dust beds some more fossils were collected. The rocks here are red fossiliferous shales' red dusts & gray shales with a few thin sandstone bands in calcareous lodes and nodules. Dip 70° W.5°. Strike E.W. Fossils Lingulae? morderpsis?, Serpocida (Bothrophus?) are abundant here. These rocks, Eastport 3.44.7d are 30 or 40 feet stratigraphically below 7c. The shales containing with a dip of 27° strike nearly E.N.W. to the south as far as the beds cross shown on the map, at the east marked in blue pencil occurs a solid continuous layer of red dust (spot check) with the usual net work structure just like the dust occurs a layer full of angular shambes of [illegible], ash fragments and also containing fossils.