Brasier, A. T.Rogerson, M. R.Mercedes-Martin, R.Vonhof, H. B.Reijmer, J.J.G.2016-09-302016-09-302015-10Brasier, A T, Rogerson, M R, Mercedes-Martin, R, Vonhof, H B & Reijmer, J J G 2015, 'A Test of the Biogenicity Criteria Established for Microfossils and Stromatolites on Quaternary Tufa and Speleothem Materials Formed in the “Twilight Zone” at Caerwys, UK', Astrobiology, vol. 15, no. 10, pp. 883-900. https://doi.org/10.1089/ast.2015.12931531-1074ORCID: /0000-0001-6103-2848/work/41343977http://hdl.handle.net/2164/7558Natural Resources Wales and Steven Griffiths are thanked for access to Caerwys quarry and permission to work on the site. Sebastiaan Edelman and Thomas Logeman assisted with fieldwork and provided some of the field photographs. Bouke Lacet (Sedimentology laboratory, VU University Amsterdam) prepared the thin-sections. Three anonymous reviewers helped to sharpen the manuscript, and Sherry Cady provided valuable editorial advice and assistance. A.T.B. was inspired by Martin Brasier. He dedicates this manuscript to his father’s memory.191356663engmicrofossilstromalitebiogenicitycarbonatetufaspeleothemQE GeologyQEJournal article10.1089/ast.2015.12931510