ACKNOWLEDGMENTS

This contribution must acknowledge Rep, himself, because it began as a coauthored manuscript. We abandoned that effort because it became apparent that the assemblage was a composite, and further, that it was not possible, given data then at hand, to reconstruct the origin of the fossils. The present product differs from our original attempt to advance microtine biochronology. Still, the conclusions drawn here were stimulated by Rep's thinking and publications. Richard Tedford also provided crucial supporting information, and he found the important locality YS5. Zheng Shaohua also kindly supplied information and came to the similar conclusion of multiple origins for the Nan Zhuang Gou assemblage. I acknowledge the collegial collaboration of IVPP and the Yushe field team, including Qiu Zhanxiang, Wu Wenyu, Will Downs, and Neil Opdyke, and thank the editors for the opportunity to present this tribute.