La Brea Tar Pits

During The Hesperus Prophecy, spring thaw causes the roadways near the US Naval Research Labs to behave less like gravel and more like chocolate pudding, the car tires sinking into the mud like a saber-tooth cat trapped in a La Brea tar pit.

This is a reference to the La Brea tar pits located in Los Angeles, California. Tar pits formed where natural asphalt seeped up from the ground for tens of thousands of years. When animals got stuck in the tar they attracted attention from predators, who were also trapped. This is how the La Brea tar pits became a treasure trove of well-preserved animal specimens, including several extinct species such as mastodons and saber-toothed cats.

Saber-toothed cat

Mastadon