Review of Recent Geological Literature. 53 
tiary species from all localities in North America are described, being 
as follows : Myriapoda, 1 ; Arachnida, 34 ; Neiiroptera, 66 ; Orthoptera, 
30 ; and Hemiptera, 266. The collections of the higher orders from the 
wonderfully rich insect-bearing beds of Florissant yet remain to be 
elaborated ; and for these orders the present volume contains only the 
species known from other localities, these being of Coleoptera, 112 (in- 
cluding 37 Pleistocene species); Diptera, 79; Lepidoptera, 1; and Hy- 
menoptera, 23. The total number of species thus described is 612, of 
which 57.5 are from Tertiary formations, mostly called Oligocene, in 
Colorado, Wyoming, Utah, and British Columbia. Of the Pleistocene 
species, 26 were collected by Mr. George J. Hinds in the interglacial 
beds of Scarboro Heights on the north shore of Lake Ontario near 
Toronto, none of them identifiable with existing species ; and 11 others, 
likewise now extinct, were found in bone caves at Port Kennedy, Penn- 
sylvania. 
When the study of the Florissant collections shall be completed, they 
will add according to Mr. Scudder's estimates, about 425 species of 
Coleoptera, besides many Diptera and Hymenoptera. Seven butterflies 
from the Florissant beds have been previously described by Mr. Scud- 
der in the Eighth Annual Report of the U. S. Geological Survey ; and 
since then another species of exceptional importance has been found. 
There are also probably eight species of Florissant moths. 
The Florissant lake basin lies at an altitude of about 8,000 feet in a 
narrow valley of the Front Range of Colorado, near Pike's Peak. Its 
length is 7 or 8 miles, with a maximum width of V/^ miles. Its sedi- 
ments attain a thickness of 50 feet or more, and consist of volcanic sand 
and ash, with which, in the upper half, myriads of plants and insects 
are entombed. The layer in which the insects are most abundant and 
best preserved has a thickness of about two feet. Lesquereux concluded 
from his investigation of the fossil flora that the climate at the time of 
deposition of these beds Was much warmer than now, being nearly as at 
present on the northern shores of the Gulf of Mexico. The few fishes 
found in the same lacustrine deposits also Indicate, according to Cope, 
a warm temperate climate ; and the insects, as Mr. Scudder believes, fully 
sustain this opinion. No very definite determination of the age of the 
strata has been reached, but they are referred provisionally to the lower 
Miocene or Oligocene. Only slight disturbances have taken place since 
their deposition, for they are still horizontal in their northern part, 
while their southern part has been uplifted so as to give a northward dip 
of about two degrees. The inclination caused the lake to be emptied, 
and since then subaiirial erosion has channeled the basin mostly to a 
depth of 30 or 40 feet, removing the greater portion of Its fossiliferous 
beds, but leaving plentiful remnants of them along its shores and about 
its islands. 
In this branch of paleontology, Mr. Scudder has been almost the sole 
worker on this continent, and the present volumes well attest his in- 
dustry and the wealth of his materials. 
