- Raton Formation
The Raton Formation is a geological formation of
Upper Cretaceous andPaleocene age which outcrops in northeastNew Mexico and southeastColorado .The Raton Formation was originally named "Raton Hills Group" by Hayden in 1869 for coal beds in the Raton Hills in
Colfax County, New Mexico . In 1913, Lee changed the name to Raton Formation. Lee described the formation in USGS Professional Paper 101 (pp 55-61) as a coal with carbonaceous shale with brown to buff sandstone and conglomerate (usually at the base). The Raton Formation is about 1140 feet thick at the type locality. The formation unconformably overlies the Vermejo Formation, and unconformably (?) underlies the Poison Canyon Formation.In 1954, Brown (GSA v. 54, pp 65-86) determined that the Raton Formation was of Late Cretaceous and Paleocene age.
Pillmore, 1969 (Mountain Geologist v. 6, p 129) measured the formation thickness as 2000 feet, and divided the Raton Formation into three divisions. The lowest division is a basal
sandstone and conglomerate ofquartzite ,chert andgneiss pebbles and cobbles in a coarse-grained quartzose to arkosi sandstone matrix. The middle division is fine to coarse grained sandstone, with some siltstone, mudstone, and coal. The upper division is coal-bearing and contains sandstone, siltstone, mudstone, shale, and mineable coal. [M.E. Maclachlan, New Mexico Geological Society Guidebook, 27th Field Conference, Vermejo Park, 1976]References
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