. Bulletin of the Geological Society of America. Geology; Geology -- United States. ;i6 PROCEEDINGS OF COLUMBUS MEETING. Structure and Age. Sections.—The five sections herewith (figure 5) show the structural relations. In section .1, which crosses the lowest part of the saddle, the Cambrian quartzite forms on the eastern side an anticlinal and a synclinal, the latter infolding some 65 feet of the lower part of the Stockbridge limestone. West of this, owing to a fault, a block of this limestone about 650 feet wide has slidden down between two masses of quartzite. Beyond the quartzite dips norma
. Bulletin of the Geological Society of America. Geology; Geology -- United States. ;i6 PROCEEDINGS OF COLUMBUS MEETING. Structure and Age. Sections.—The five sections herewith (figure 5) show the structural relations. In section .1, which crosses the lowest part of the saddle, the Cambrian quartzite forms on the eastern side an anticlinal and a synclinal, the latter infolding some 65 feet of the lower part of the Stockbridge limestone. West of this, owing to a fault, a block of this limestone about 650 feet wide has slidden down between two masses of quartzite. Beyond the quartzite dips normally under the limestone, and this includes a bed 25 feet thick and about a quarter of a mile long filled with fossils, determined by Mr, ('. I>. Walcott as Hyolitlies americamis, Billings,* with the fol- lowing species doubtful: //. imper, IT. communis and //. similis (very doubtful) ; the whole indicating, as he writes, t '"The upper horizon of the lower Cambrian or Olenellns ; As there are about 470 feet of limestone between this bed and the underlying quartzite, that much of the limestone must be regarded as Cam- c FAULT CLEAVA&E ; s;i. CftmK Quartitte FAULT t^. cuavaie ; A D fj" Lonqil". CTTf* Qv&yCh t e L'*n»sronp Figure 5.—Sections through Ruttand-Dariby Ridge. brian. These pteropods appear more frequently in transverse sections, but also in every sort of section. Each individual or fragment generally forms the center of a concretion-like body from ] to 1 inch in diameter (figure 6). These bodies, how- ever, require further study. The rock is bluish-gray. The oolitic structure appears best on weathered surfaces. In section />', about a quarter of a mile north of .1, the eastern fault-plane alone appears, the western having died out or merged into it. Mere the quartzite shows a synclinal and an anticlinal, and is broughl by the fault to the level of the schists overlying the limestone. *E. Billings—"On some
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