[3] It is a thick sequence of massive, cliff-forming limestones and dolomites that was named for Eldon Switch on the Canadian Pacific Railway near Castle Mountain in Banff National Park by Charles Doolittle Walcott,[1][2] who discovered the Burgess Shale fossils.

[4] The Eldon Formation is a thick sequence of cliff-forming carbonate rocks that was deposited during the Middle Cambrian time.

It originally formed as limestone and calcareous mudstone in the intertidal to supratidal zone along the western margin of the North American Craton.

[1] The Eldon Formation is present in the southern Rocky Mountains of southwestern Alberta and southeastern British Columbia.

It reaches a maximum thickness of about 500 metres (1,640 feet) at Mount Bosworth on the Alberta-British Columbia border.