Thunder Bay Limestone

Due to negligence by multiple later workers, the area was later referred to as the Partridge Point Formation by Warthin & Cooper in 1935.

It wasn't until 1943 that Warthin & Cooper would rename the formation back to its original name.

The environment that the formation represents is a shallow carbonate platform with large amounts of coral and shelly fauna.

Later formations show an increase in depth as water levels raised in the Eastern Interior seaway.

Eventually, younger formations, like the Squaw Bay limestone, would show a deep basin environment.

Stratigraphy of the Devonian deposits of the northern part of the Lower Peninsula of Michigan