Origin of a widespread marine bonebed deposited during the middle Miocene Climatic Optimum Pyenson, N. D. ; Irmis, R. B. ; Lipps, J. H. ; Barnes, L. G. ; Mitchell, E. D. ; McLeod, S. A. Abstract Publication: Geology Pub Date: June 2009 DOI: 10.1130/G25509A.1 Bibcode: 2009Geo....37..519P