Chert-bearing clastic strata are a common component of Jurassic and younger terrestrial sequences in the Yukon. The discovery of dinosaur trackways in a small inlier of chert-bearing clastic strata within the Tintina Trench, 3 km west of Ross River, led to reevaluation of its sedimentary framework and previously assumed Eocene age. A mid-Cretaceous (middle Albian to early Cenomanian) age is inferred from a miospore assemblage that includes the angiosperms Cupuliferoidaepollenites minimus, Retitricolpites prosimilis, Retitricolpites virgeus and Senectotetradites amiantopollis. The trackways are preserved on at least three levels within the >427 m of section exposed along and north of the Robert Campbell Highway. They occur in splay deposits associated with small, sandy meandering rivers that flowed parallel to the direction of the Tintina Trench. Most trackways appear to be heading towards the southeast, suggesting systematic migration patterns during the wet season. Conglomeratic strata were deposited by wandering gravel-bed rivers that also flowed parallel to the trench. Individual channels were up to 12 m deep and more than 50 m wide.
