Late Pleistocene Marine Terraces on Santa Rosa Island, California

Coastal tectonics on the eastern margin of the Pacific Rim: late Quaternary sea-level history and uplift rates, Channel Islands National Park, California, USA

“…Exposures that were examined along the outer part of Garañon Canyon (SRI-5D,E,G,H,J localities in Fig. 8) in the present study display two late Quaternary marine terraces that are believed to be the equivalent of Orr's (1960Orr's ( , 1968)~7 m and~23 m terraces and their associated sediments, what Orr (1960Orr ( , 1968 called the Garañon Member and Fox (informal) member of the Santa Rosa Island Formation, respectively. In Garañon Canyon, the shoreline angle elevation is 7.4 m for the lower terrace and~24 m for the higher terrace (Fig.…”

“…On Santa Rosa Island, Orr (1960Orr ( , 1968 reported a fauna from the 2nd terrace, collected at or very close to our fossil localities SRI-5-D, E, F, and J, based on records obtained through the courtesy of Dr Paul Valentich-Scott of the Santa Barbara Museum of Natural History. An examination of this fossil list with updated, modern zoogeography reveals that the 2nd terrace on Santa Rosa Island also contains a mix of species with differing thermal aspects.…”

“…1), based on information in Keen (1971). On the other hand, according to Orr (1960Orr ( , 1968, deposits of the 2nd terrace also host C. stelleri, which presently is rare south of Monterey Bay and H. rufescens, which is uncommon south of Point Conception, as discussed above. In addition, Orr (1960Orr ( , 1968 reports that the 2nd terrace hosts an extralimital northern gastropod, Stylidium eschrichtii (Middendorff, 1849), which ranges from the Kenai Peninsula of Alaska or possibly Ketchikan, Alaska [LACM 165048] to only as far south as San Luis Obispo County, California [LACM 16052].…”

“…Much of Orr's (1960Orr's ( , 1968 marine terrace work on the northwestern side of Santa Rosa Island was based on field studies conducted between Sandy Point and Brockway Point (Fig. 8), in Garañon Canyon and Arlington Canyon.…”

“…squamigeris), both of which have present ranges that occur no farther north than Point Conception (McLean, 2007) or San Luis Obispo County (LACM collections) but extend well into central Baja California. Orr (1960Orr ( , 1968) also reports Acmaea conus (¼Lottia conus (Test, 1945)), which ranges from Point Conception to as far south as southern Baja California (McLean, 1978). Also present is a chiton, Stenoplax conspicuous (¼Stenoplax conspicua (Pilsbry, 1892)) that, according to Keen (1971), has Santa Barbara as its modern northern range endpoint and lives as far south as Bahía Sebastian Vizcaino, Baja Californa (Fig.…”