Dear colleagues:

Since the Hirnantian and Katian GSSPs were ratified by IUGS, the Ordovician GSSP study remains only the last one, the base of the Middle Ordovician. I have asked the voting members read carefully the related papers on Episodes where Wang Xiaofeng and his colleagues and Albanesi and his colleagues published their reports respectively. Their reports have also been posted on the Subcommission website. I hope that the Subcommission voting members, corresponding members, as well as the Ordovician friends pay attention to this important GSSP study and post their comments on the Subcommission website.

Sincerely Yours,

Chen Xu