Hell Creek Formation
The Turtle Ridge was found by Tyler Lyson in 1997. Over 20 partial turtle shells were exposed along a quarter mile stretch of badlands and were recovered that year. The first serious excavation of this area began in 2007 where over 25 shells, multiple skulls, and many completely articulated specimens were collected.
The Turtle Ridge is stratigraphically equivalent to the Turtle Graveyard locality, which lies less than a third of a mile away. The Turtle Ridge consists of rich pockets of fossil turtles, namely from the baenid Stygiochelys. Unlike the Turtle Graveyard, many of the specimens are completely articulated, with one such specimen preserving a tail that is just under 80 centimeters long!!
The sedimentology and fossil material suggest that the area is a channel deposit. Given that the locality is stratigraphically equivalent to the TG and that the skeletons are found closely associated to one another in pockets throughout the ridge, the taphonomic history of the Turtle Ridge may be similar to that of the Turtle Graveyard in that a river channel dried up during a drought, forcing the turtles into shrinking pools of water where they died. Like the Turtle Graveyard locality, the turtles were later buried during a flood event.