In Creation Research Society Quarterly 2015 51: 286-298

According to secularists, the top of the Hell Creek Formation records the last of five great extinctions. It has gained further fame as a unit that documents the disappearance of dinosaurs in the Western United States. The so-called Cretaceous-Paleogene (K-Pg) extinction is more complicated than many are led to believe, and is probably just the last appearance of many organisms in Flooddeposited strata. The Hell Creek Formation extends across eastern Montana and parts of North and South Dakota, varying from 170 m to 41 m thick. The base of the formation is picked where the composition of the underlying sandstone layer (Fox Hills Formation) changes to carbonaceous sandstone, marking the lowermost bed of the Hell Creek Formation. The top of the unit is more complicated. In the past, changes in the stratigraphy and/or fossils were used to pick the upper boundary, but now secularists choose the Iridium-rich layer as the top, regardless of other geological data. Limited occurrences of an Iridium anomaly make picking this top problematic in many locations. The type section shows ample evidence of water deposition. Marine fossils, including sharks, bivalves, and gastropods, are prevalent throughout the Hell Creek, not just in isolated lenses as many have claimed. Patterns of dinosaur occurrences in the uppermost Hell Creek show less dinosaur fossils toward the top of the formation and a 2–3 m gap at the very top that is devoid of dinosaur fossils. Dinosaur fossils found in the overlying lowermost Paleocene Fort Union Formation, may indicate some dinosaurs survived until the end of the Zuni Megasequence, slightly above the K-Pg. All geological data observed in the Hell Creek Formation are interpreted as occurring during a worldwide Flood event. Stratigraphic data, such as ripples and cross-bedded sandstones, demonstrate water transport. Marine fossils found throughout the formation imply a strong marine influence during deposition of the entire unit. The observed mixing of land and sea organisms is best explained by tsunami-like waves transporting ocean waters onto the continent, engulfing the terrestrial animals and depositing the Hell Creek Formation.

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