Chamberlain's Brook Formation

The Chamberlain's Brook Formation is a thin but distinctive geologic formation of dark red calcareous mudstones^[3] that crops out from Rhode Island to Massachusetts and, Nova Scotia, New Brunswick and Newfoundland.^[2] It preserves fossils, including trilobites, dating back to the lower mid-Cambrian period.^[2] Its lowermost member is the Braintree Member (lowest Middle Cambrian) and the uppermost member is the Fossil Brook Member.^[2]

Chamberlain's Brook Formation
Stratigraphic range: Middle Cambrian ~509–506 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓
Type	Formation
Unit of	Adeyton Group[1]
Sub-units	Fossil Brook Member (and others)
Underlies	Manuels River Formation (unconformably?)[2]
Thickness	up to 14 m (46 ft)[2]
Lithology
Primary	Green, purple and red siliciclastic marine mudstones[2]
Location
Region	Atlantic coast
Country	United States Canada
Occurrence of the Chamberlain's Brook Formation in southeastern Newfoundland

See also

• List of fossiliferous stratigraphic units in Massachusetts
• Paleontology in Massachusetts
• Inlet Group