There are five letters in this week’s PNAS, responding to an article by Isabel Israde-Alcántara et al., that came out earlier this year on purported impact markers in Lake Cuitzeo, Mexico. In one letter (Gill et al. 2012), my coauthors (Jessica Blois, Simon Goring, Jenn Marlon, Pat Bartlein, Andrew Scott, and Cathy […]

Estimated reading time: 1 minute