1890.] Origin of the Plane-Trees. 809 
Tertiaries, and in the Fort Union group and other deposits in the 
United States that are below the Green River group, and have 
been sometimes regarded as Laramie. If Tertiary at all, they 
belong at the very base of that series. Specimens have even 
been collected in the Bozeman coal mines, which Dr. Peale, who 
has devoted many years to their study, regards as Cretaceous. 
In the form of Acer trilobatum, which Lesquereux did not con- 
sider a Platanus, it also occurs in the Green River group on 
Troublesome Creek, Colorado, generally regarded as Eocene. 
It, therefore, doubtless also had its origin in the Cretaceous of 
America. 
P. aceroides academie Jankó (P. academie Gaudin) is only 
known from the Upper Miocene deposit of Montemasso, Italy, 
and has no importance. 
P. aceroides dissecta Jankó, including P. dissecta Lx., and P. 
appendiculata Lx., is confined, so far as now known, to the Upper 
Tertiary (Pliocene or Quaternary) of California (Chalk Bluff, 
Corral Hollow, Spanish Peak, Toulumne and Nevada Counties). 
The latter form, as I have shown, approaches very closely the 
American sycamore, P. occidentalis, and connects it by its basilar 
appendage with P. basilobata of the Fort Union group. 
P. marginata (Lx.) Heer (Viburnum marginatum Lx.), the last 
species to be considered, is primarily a typical Laramie (Bitter 
Creek) species, but also occurs in the Denver formation at Golden, 
Colorado. Like so many other Laramie species, it is found in 
the Tertiary deposits of Greenland, where Heer first discovered 
its platanoid character. It is, therefore, not a Miocene species at 
all, but a Cretaceous species extending into the Eocene. 
This hasty review enables us to revise the geological distribu- 
tion of the fossil species of Platanus given by Professor Janko, 
which should therefore stand as follows: 
I. Exclusively Cretaceous species.—P. newberryana and 
primeva. 
. II Species originating in the Cretaceous, but extending into 
the Tertiary —P. primeva heeri, marginatum, and raynoldsu integ - 
