THE MYLAGAULID£Z— RIGGS. 
DISTRIBUTION 
IN NORTH AMERICA. 

John Day. 
MIOCENE. 
Deep 
River. 
OF SCIUROMORPH RODENTS 


Geomyide: 
Gymnoptychus montanus 
g trilophus . 
Fleliscomys vetus. 
Pleurolicus leptophrys . 
Entoptychus crasstramts 
sy plantfrous . 
Castoridz: 
Steneofiber nebrascensts 
ns peninsulatus 
"<  pansus 
i gradatus 
* montanus 
Eucastor tortus 
Castor fiber 
“  pelicedens 
2 YOSINE 
Sciuride: 
Arctomys vetus 
u MOnNaAX 
. Sosstlis 
Scturus relictis 
ri vortmant 
a calycinus 
“ — panolius 
Tamtus lavideus . 
Meniscomys liolophus 
i cavatus 
ot niteus 
Mylagaulide: 
Protogaulus hippodus 
Mesogaulus ballensis 
Mylagaulus sesquipedalis 
* monodon 

ee Pie S 
a 


x xX X 






Plio- |Pleisto- 
cene. | cene. 
os g oe 
5 = SA 
vo onl o 
Zz Q oO 
x 
x 
x 
x x 
x 
x 
x 
x 
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