@katyabandow Yeah, there are a couple; the bottom one is Johnson, 2002 (https://t.co/PbrHPeetxH), the left one is Taylor et al., 2009 (https://t.co/3LDa9Nlg0O), and the top two are Pott et al., 2016 (https://t.co/SKAjR6DCec).
The Hell Creek Formation and the Cretaceous-Tertiary Boundary in the Northern Great Plains
Geological Society of America