Crowleys Ridge (Cretaceous of the United States)

Where: Stoddard County County, Missouri (36.9° N, 89.8° W: paleocoordinates 40.6° N, 66.3° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Discoscaphites iris ammonoid zone, Owl Creek Formation, Late/Upper Maastrichtian (70.6 - 66.0 Ma)

• "This excavation exposes the latest Cretaceous Owl Creek Formation and earliest Paleocene sediments of the Clayton Formation, bracketing the Cretaceous-Tertiary (K/T) Boundary (Fig. 2). The K/T section is overlain by 50 meters of Porters Creek Formation of later Paleocene age, with 35 meters of Eocene sediments above this."

•"A similar association is seen in New Jersey .... an age estimate for the D. iris zone in New Jersey of 65.4 ± 0.2 Ma to 65 Ma, essentially coincident with current age estimates for the K/T boundary."

Environment/lithology: lithified, shelly/skeletal limestone and poorly lithified, bioturbated, glauconitic, nodular claystone

• "The detailed stratigraphy of the K/T section at this site is divisible into three units (Campbell and Lee, 2001):

•1. At base, a bioturbated glauconitic clay containing a diverse Cretaceous invertebrate fauna, burrows, planktonic foraminifera, and phosphatic nodules (Owl Creek Formation);

•2. In the middle, an unsorted limestone coquina with Cretaceous invertebrates, planktonic foraminifers and microtektite spherules in rip-up clasts (K/T);

•3. On top, a well-indurated unfossiliferous limestone speckled with glauconite grains (Clayton Formation)."

Size class: macrofossils

Collection methods: quarrying, mechanical,

Primary reference: W. B. Gallagher, C. E. Campbell, J. W. Jagt and E. W. A. Mulder. 2005. Mosasaur (Reptilia, Squamata) material from the Cretaceous-Tertiary boundary interval in Missouri. Journal of Vertebrate Paleontology 25(2):473-475 [M. Carrano/H. Street]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 97842: authorized by Matthew Carrano, entered by Hallie Street on 31.08.2010

Creative Commons license: CC BY (attribution)

Taxonomic list

Reptilia
 Squamata - Mosasauridae
Mosasaurus hoffmanni Mantell 1829 mosasaur