Eastport quadrangle notebook # 1, 1907
Page 16
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Transcription
Friday July 5, 1907 Birch Point. (Section see p. 18) 22 (A) On the point between tide marks and continuing just above high tide are exposed sand 35 or 40 feet of which is coarse, sandy flag of a light gray color with a few slimy outcappings of purple shale. These chalk flags are as much as 6 to 10 inches thick but split into 1/2" to 2" slabs. Marine hummocks are abundant on these flags. Strike 5.75° W. Dip N 15° W, 26°. No fossils found in 20 minutes. No calcareous seams nor nodules. Near the top occurs one or two thin "cotton" seams; also a half inch seam composed of angular chert fragments. (B) The preceding are overlain by about 20 ft. of light gray, even textured chalk flaggy free-stone like rock which weathers nearly white and turns thin brown under acid but with no difference whatever. Strike S (approximately) 75° W. These rocks are exposed for a couple of hundred feet along the beach above high tide. The dip is 26°, N 15° W. During the fact that the eastern side of the point trends north a few degrees west giving an apparent inclination of the rocks to the east whereas the westerly side drops toward the west, there is this appearance of an anticline but this does not exist as the same strikes (S 75-80° W.) and dips (26° N. 15° W.) are maintained on both sides, and the apparent fold is therefore due to the bend of the cliff. The rocks include a few calcareous seams 1/2 inch thick and a couple of Oolitic bands (calc spidotic) 1/2 inches thick which weather cream white & contain Sporodites. The Sporodites were collected just below end of the top of Birch Pt. (= 6.13a, and a foot higher, 6.13a-2). Many of the layers contain large & distinct sun shrinkage cracks and a few contain fissures to rain prints; no more marks. The outcrop on the west side of the Point for a couple of hundred ft is at a small angle from the strike so that the rocks appear to nearly level. (C) For 75 ft. along the beach, the beds are abruptly disordered and bordered by lobing and the strike abruptly changed. Strike N 270° E x S 21° W or a change of about 56° giving toward the south. The dip is 27° W x 30° N. The rocks are flaggy flaky beds baked hard and a few thin calcareous seams and near the southeast end the rock is extremely brecciated and winded. There is here a fault trending N 15° W by S 15° E but the rocks on both sides of the fault are apparently the same except for the lobing, containing similar fissures & large shrinkage cracks and in one or two cases pebbles full which less are traceable. There is no strike in the vicinity. The top of the faulted area is formed by a chalk massive 5 feet thick which may be followed on both sides the fault but is not displayed either vertically or horizontally except to the south and this apparently at the angle of deflection of the strike where the fault is situated. The structure is evidently due to lateral torsion and deflection of the line of strike by a laterally thrusting force but without any vertical deflection. 6/3 A granite sill 26° Timber Cove Bell's Ice Bells' Cove 23 8