FOSSIL INSECTS FROM THE ROCKY MOUNTAINS. 665 
The tallest tree in proportion to its girth. The largest shafts 
are probably over one hundred feet, and the greatest circumfer- 
ence about seventeen or eighteen feet; while many trees no doubt 
exceed one hundred and sixty feet in height. 
SASSAFRAS (Sassafras officinale). 
Height 713 feet. Mean of 3 trees. 
Trunk 524} «“ Pet Ax Ghee 
Cire. 72 te 6 «g 6c 
Though usually considered one of the “ underwoods,” this tree 
is not unfrequently of these dimensions in very rich woods. 
FOSSIL INSECTS FROM THE ROCKY MOUNTAINS. 
BY SAMUEL H. SCUDDER. 
SEVERAL years ago, Professor William Denton discovered in 
shales lying near the junction of the Green and White Rivers in 
Colorado (?), the first traces of tertiary insects on this continent. 
They were found in two distinct localities, sixty miles apart, the 
Specimens from one place differing from those of the other, not only 
Specifically, but also to a very great extent in the general character 
of the whole assemblage.* Reports of these discoveries attracted 
the attention of those who afterward explored parts of the Rocky 
Mountain region, and repeated inquiries were made concerning the 
exact location of the insectiferous beds. These explorations have 
resulted in the discovery of more fossil insects in the same gener: 
region by Mr. F. C. A. Richardson, who accompanied Major 
Powell’s exploring party, and by Dr. Hayden in some of his 
humerous and fruitful researches. The latter brought home only 
three Specimens, two flies and an ant, but the collections of the 
former are more numerous and afford material for the present 
notice, 
Some doubt exists as to whether the insects discovered by Prof. 
tma See Proc. Bost. Soc, Nat. Hist., xi, 117-118. A detailed and illustrated Report upon 
ese fossils, which Mr, Denton kindly lent for a long period of examination, 
