The publisher apologises for the omission of a Reference from the Reference list on page 349. That Reference is given below:

Schomberg A., Wemmer K., Warr L.N. & Grathoff G. (2019) K–Ar age determinations on the fine fractions of ‘Crystallinity Index Standards’ from the Palaeozoic mudrocks of southwest England. Clay Minerals, doi:10.1180/clm.2019.3.

You do not currently have access to this article.