. Bulletin of the Geological Society of America. Geology. NON-MARINE PROGRESSIVE OVERLAP 629 the marine, though in reality it is more a replacement of the one by the other. The following diagram will make this clear:. Figure 12.âOverlap Relation of marine and non-marine Beds. EXAMPLES OF NON-MARINE PROGRESSIVE OVERLAP Chemung-Catshill.âA typical example of the last described type of overlap is seen in the case of the Catskill and Chemung formations of New York and the northern Applachians generally. Here the non-marine Catskill begins in Portage time as the Oneonta, and is gradually but progre
. Bulletin of the Geological Society of America. Geology. NON-MARINE PROGRESSIVE OVERLAP 629 the marine, though in reality it is more a replacement of the one by the other. The following diagram will make this clear:. Figure 12.âOverlap Relation of marine and non-marine Beds. EXAMPLES OF NON-MARINE PROGRESSIVE OVERLAP Chemung-Catshill.âA typical example of the last described type of overlap is seen in the case of the Catskill and Chemung formations of New York and the northern Applachians generally. Here the non-marine Catskill begins in Portage time as the Oneonta, and is gradually but progressively pushed westward and northwestward until it has reached the very summit of the Chemung. Thus in the Ithaca region the red sedimentation of the Catskill type does not begin until upper Chemung time. In the Olean region farther west it begins in the Cattaraugus beds above the Chemung (Devono-Carbonic transition). Thus, while the Chemung is fully developed in western New York, it is absent in eastern New York and Pennsylvania, where the Catskill type of sedimentation alone occurs. Between these two points both are seen, the non-marine always overlying the marine. This relationship is shown in the following diagram: -V â V - V"; t --- ~^- =^~k~irJ% â V 4^s - â â - ---tL-^o/7- rnart'n e~~SS. N.â â>v â\ V â \ e m u /7 q â â \ â\- : /7?q r/?ie vâ \ - \ - V - V X N- -x - N \ â -> - - -V-â "Nr~â- *\ â \- \ â > â\ \- â S ~ "x -^L.^, "C â¢=â - "- VI-I- V^""->~ âV â\ â\ â \ - â \ > â \ â X N â â \ â ^ â\ â s-^^^«â~-^----~- Figure 13.âOverlap Relation of marine Chemung and non-marine Catskill Beds. The Pocono.âThis is the .lowest of the Appalachian Lower Carbonic formations and represents the continued non-marine sedimentation from the Appalachians northwestward to the western Pennsylvania region. The original easternmost extension of this formation, as of the preceding and succeeding non-m
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