McCaslin formation. Formation unconformably overlies Waupee series (new). Composed of a basal conglomerate which grades upward into clean quartzite. Maximum thickness about 5,000 feet. Unconformably underlies Hager rhyolite porphyry (new). In contact with younger High Falls granite (new) in several areas. McCaslin formation furnishes structural framework for regional [McCaslin] syncline. Middle Precambrian or Huronian but exact position in Huronian not clear.
Source: US geologic names lexicon (USGS Bull. 1350, p. 448-449).
Pg. 2, 3 (geol. map), 5, 8. McCaslin quartzite. Presumably same as Thunder Mountain quartzite (new). Study area in vicinity of McCaslin syncline in southeastern Forest, western Marinette, and northern Oconto Counties, Wisconsin. Age not stated.
Source: US geologic names lexicon (USGS Bull. 1350, p. 448-449); GNU records (USGS DDS-6; Denver GNULEX).
Pg. 7-14. McCaslin Quartzite. A review of some problems of Precambrian geology of northeastern Wisconsin. Mancuso (1957, 1960, unpub. theses) established following succession: Waupee Volcanics, Macauley Granite, Baldwin Conglomerate and McCaslin Quartzite, Hager Rhyolite Porphyry, Belongia Granite and High Falls Granite. Significant contribution of this study was demonstration of two distinct ages of granitic intrusion: McCaslin Quartzite lies nonconformably on Macauley Granite and is intruded by High Falls Granite.
Source: US geologic names lexicon (USGS Bull. 1350, p. 448-449).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
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