280 Annals of the Carnegie Museum. 



different in appearance from those of Glendive and Bear Butte. 

 Though I have not visited the typical locality of the Fort Union near 

 the mouth of the Yellowstone River, I have read nearly all the de- 

 scriptions of them by travellers and geologists, and these accounts 

 lead me to infer that the lithological characters of the strata at the 

 typical locality are nearly the same as those of the Little Missouri 

 beds, and that parts of the same series might be traced from one 

 locality to the other. 



Fossil plants have been collected in all the above named localities and 

 all have been pronounced by experts to be of Fort Union age ; but on 

 account of the absence of good collections from the various horizons 

 of the Eocene, which have been sharply distinguished by their succes- 

 sive mammalian faunas, it is uncertain just how many of the Eocene 

 horizons are covered by the Fort Union. The Glendive beds ap- 

 parently lie beneath the Little Missouri beds, and probably beneath 

 the typical Fort Union. If the Bear Butte Beds — which are cer- 

 tainly Lower Eocene, as they contain Torrejon, and perhaps Puerco 

 mammals — are nearly or quite contemporaneous with the Glendive 

 beds, it is quite possible that the Little Missouri strata, and the typi- 

 cal Fort Union may be contemporaneous with the Wasatch, or may 

 possibly be later. I understand that plants have been found in the 

 Wasatch of the Big Horn Basin. If so comparisons of the fossil floras 

 will be interesting. Remains of reptiles have been found in the Bear 

 Butte and Glendive beds, but they have not yet been made available 

 for determining horizons. 



The subject is a large and interesting one, and will probably involve 

 not only the collection and study of the vertebrates as well as the 

 plants of the northern beds, but the obtaining of collections of plants, 

 as well as animal remains, from the Eocene and supposed Eocene beds 

 of Wyoming, Utah, New Mexico, and other regions. 



As thoroughly competent paleontologists and field-parties of the U. 

 S. Geological Survey have taken up the task of settling some of the long 

 standing problems of Upper Cretaceous and Lower Tertiary geology, I 

 will, for the present, refrain from further discussion of the question. 

 There is no doubt, however, that the Fort Union is entirely distinct 

 from the Laramie, and there are apparently several horizons of the 

 so-called Fort Union. 



