Editing Front Range (section)

===Benton Group / Niobrara Formation===
Over the next 35 million years, the Cretaceous seaway repeatedly widened as far as Utah and Wisconsin and narrowed to near closure.<ref>{{cite journal |author= R.J. Weimer |year= 1984 |journal= AAPG Memoir |title= Relation of unconformities, tectonics, and sea-level changes, Cretaceous of Western Interior, United States |editor= J.S. Schlee |publisher= [[American Association of Petroleum Geologists]] |issue= Memoir 36, Interregional unconformities and hydrocarbon accumulation |page= 407 |url=https://terra.rice.edu/department/faculty/morganj/ESCI536/Readings/Weimer_CretaceousSeaway.pdf |access-date= March 21, 2021 }}</ref> With no mountains present at the time, the Colorado area was in the line of the deepest channel of the seaway; but being on the [[Transcontinental Arch]], the Front Range areas was relatively shallow and was near the last land to submerge as the seaway opened. Shale and chalk were deposited over the area as [[Greenhorn Limestone|Greenhorn]] of the [[Benton Shale|Benton Group]] and the [[Niobrara Formation]]. Within these beds are found abundant marine fossils ([[ammonite]]s and skeletons of fish and such marine reptiles as [[mosasaur]]s, [[plesiosaur]]s, and extinct species of [[sea turtle]]s) along with rare dinosaur and bird remains. Today, the [[Fort Hays Limestone Member|Fort Hays Limestone]] member forms [[Flatiron (geomorphology)|flatirons]] or secondary hogbacks on the east slope of the Dakota Hogback.<ref name=Noblett2011a>{{Cite book|last= Noblett |first=J.B. |title=A Guide to the Geological History of the Pikes Peak Region, Colorado Springs (2nd ed.) |publisher=Colorado College |year=2011|location=Colorado Springs, Colorado |pages=43}} ('''Benton Group''' is in current use in this location.)</ref>