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Brief statement of problem and remarks (from collector):
The age of the Totatlanika schist has been regarded as pre-Devonian, probably Ordovician, on basis of long-ranging correlation with the Tatina and Tonzona groups of the Rainy Pass region, and with rocks of the Rampart district. This is the first fossil collection to have come from the Totatlanika schist itself. Preliminary examination by C.W. Merriam, suggested that the collection includes Crinoid (?) stems, Syringopora, and possibly a piece of a Spiriferoid brachiopod. Merriam suggests that the age may lie between Silurian and Mississippian.
Interpretation of the stratigraphy and tectonic history of the Alaska Range rest on the determination of the age of these fossils.
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[additional data on location from Request for Examination of Fossils sheet of Wahraftig, 5/2/1955]
54Awg526
Field note book station No. R-1178, at 4,100' altitude on mountain west of junction of Rogers and Sheep Creeks, Healy D-2 quad. (9.45, 13.95)
Fossil crinoid stems, syringopora, and brachiopods?
Ca. 4,000-5,000 feet above the base of the volcanic pile which is the Totatlanika schist in this area, a few hundred feet below the base of a prominent black schist unit which represents the top of the volcanic Totatlanika schist. The black schist unit is overlain by ca. 2,500 feet of a sequence consisting of green and purple slate at base, grading upward into slightly arkosic sericite schist which exhibits graded bedding.
Collection is of loose angular fragments of limestone which could be traced for several hundred feet along the contour on the hillside, parallel to the bedding measured in outcrops of schistose rhyolite in nearby outcrops. Topographic position, absence of any boulders of any other rock, definitely rule out the possibility that these could be derived from terrace gravels, or any other rock than a limestone lens in the schist. Hillside covered largely with talus, so outcrop of limestone bed was not to be expected. Similar limestone was observed in Totatlanika schist, and preservation of fossils is to be expected in favorable circumstance, because igneous structures (porphyritic texture, phenocrysts, pyroclastic structure, etc.), are well preserved in the rhyolite members of the Totatlanika schist.