Response to Anonymous Referee #2

Abstract

We thank reviewer #2 for her/his time and for the constructive and helpful comments. We will incorporate many of the suggested changes and modify the manuscript to address the concerns raised. Generally, there were three major comments made, some of which were similarly made by the first reviewer (Taylor Schildgen) and we include our responses to these concerns below. The first comment is regarding the small number of modern samples analyzed. As the first reviewer made a similar point, I include here the answer given there. Unfortunately, the source area for chert nodules is very difficult to currently access and therefore C1 ESurfD Interactive comment