. Geology of the Narragansett basin. Geology. RHODE ISLAND OOAL MEASURES. 167 45° E. In the railway cut the same series of strata show a north-south vertical fault plane, the slickensides of which are horizontal. There is. Fig 21 —Geological section through rocky islets at Halsey Farm, Silver bprmg a, the rocky head shown in PI VI; R R , the railroad present a coarse slaty- cleavage, but it is not a constant feature. The joint planes display great feathery surfaces of fracture, the divergent lines of which indicate the direction of splitting; this sometimes is upward or downward, but very freq
. Geology of the Narragansett basin. Geology. RHODE ISLAND OOAL MEASURES. 167 45° E. In the railway cut the same series of strata show a north-south vertical fault plane, the slickensides of which are horizontal. There is. Fig 21 —Geological section through rocky islets at Halsey Farm, Silver bprmg a, the rocky head shown in PI VI; R R , the railroad present a coarse slaty- cleavage, but it is not a constant feature. The joint planes display great feathery surfaces of fracture, the divergent lines of which indicate the direction of splitting; this sometimes is upward or downward, but very frequently in a horizontal direction, the plane being vertical With certain precautions, the dip of massive beds can be obtained by observing the inclination of the axes of these feather fractures. The joint planes frequently die out with a convex front, the periphery being cast into concentric flexures of conchoidal fracture, often measuring an inch from trough to crest. These planes of fracture exhibit splitting figures having a length of at least 6 feet from the rather indistinct point of origin to the sharply incised marginal nigosities.^ A few rods farther south, but north of Pomham Rock, is a small rocky headland, composed of two distinct ridges, in which the following section was shown, dipping 45° E., the same rocks reappearing in the islets north- ward by the Silver Spring shore. 6 <y. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Shaler, Nathaniel Southgate, 1841-1906; Woodworth, Jay Backus, 1865-1925; Foerste, Aug. F. (Aug. Frederic), 1862-1936. Washington, Govt. Print. Off.
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Keywords: ., bookcentury1800, bookdecade1890, bookpublishe, booksubjectgeology
