. Bulletin . erts, and concretions from the lower part of this formation andfrom some of the older rocks. There are also four distinct beds of hgnitic shale, 1 to 5 feet are the fossihzed remains of former swamps. The formation is cut by some large and some small basaltic dikes(Pis. VII and XV), but these have caused scarcely any meta-morphism. Faultmg has considerably broken the beds and, owingto their soft and brittle character, relatively small faults, where themovement seems to have been less than 75 feet, have resulted in shearzones up to several feet wide. These rocks weather
. Bulletin . erts, and concretions from the lower part of this formation andfrom some of the older rocks. There are also four distinct beds of hgnitic shale, 1 to 5 feet are the fossihzed remains of former swamps. The formation is cut by some large and some small basaltic dikes(Pis. VII and XV), but these have caused scarcely any meta-morphism. Faultmg has considerably broken the beds and, owingto their soft and brittle character, relatively small faults, where themovement seems to have been less than 75 feet, have resulted in shearzones up to several feet wide. These rocks weather readily, and are a Hill, R. T., Geological history of the Isthmus of Panama and portions of Costa Bica: Bull. MuseumComparative Zoology of Harv-ard College, vol. 28, 1S9S. 6 Howe, Ernest, Canal Commission Ann. Report 1907, Appendix E, pp. 10&-13S; Isthmian geology ofthe Panama Canal: Econ. Geol., vol. 2,1907, pp. 639-658; Geology of the Isthmus of Panama: Am. , vol. 26, ser. 4, 1908, pp. BUREAU OF MINES BULLETIN 86 PLATE VII
Size: 1207px × 2070px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectminesandmineralresou
