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The article presents an author's reply to the discussion regarding the burrow dug by large vertebrates in Utah which was declared by George P. Oldier as rain-moistened middle Jurassic sand dunes. He stated that Odier's article in 2007 is concerned with his mistakes in interpreting the structures maintained in the Entrada Sandstone as burrows and the uncited work of Odier in its 2006 article on the burrows in the Navajo Sandstone. He said that Odier's article in 2007 interpreted the burrows as wells formed by heavy rain falling on dune sand. He reasoned out that rain-wetted blocks of cohesive sand occasionally move down steep lee faces of dunes.

A dinosaur trackway in the Middle Jurassic eolian Entrada Sandstone of southern Utah, U.S.A., exposes three undertracks that we have modeled as isolated tectonic regimes showing the development of fold-thrust ramp systems induced by the dinosaur's feet. The faulted and folded sequence is comparable to crustal-scale tectonics associated with plate tectonics and foreland fold-thrust belts. A structural analysis of the dinosaur tracks shows the timing and direction of the forces exercised on the substrate by the animal's foot during the stride. Based on the structural analysis, we establish a scenario for foot movements and weight distribution in the feet. During the end of the weightbearing phase of the stride, the weight of the animal was transferred to the front of the digits, creating a rotated disk below the foot that was bounded by an extensional fault at the front and a thrust ramp toward the back. As the body accelerated, the foot was forced backward. The rotated disk was forced backward along a detachment fault that was bounded by lateral ramps. The interramp segment matches the width of the dinosaur's foot, which created an imbricate fan thrust system that extended to the far end of the undertrack. The total length of the tectonic disturbance created by the dinosaur is up to three times that of the original footprint. Early, near-surface cementation gave the substrate the rheological properties necessary for development of the observed structures. [ABSTRACT FROM AUTHOR]