LETTER OF TRANSMITTAL, 
YALE COLLEGE, New HAVEN, ConN., 
June 1, 1876. 
Srp: We have the honor to hand you herewith a report on the geology of a “ Reconnaissance 
from Carroll, Montana, to the Yellowstone Park, and return,” made under your couimand during 
the months of July, August, and September, 1875. 
In submitting the narrative of our examination of the country passed over, we wish to express 
to you our grateful appreciation of your uniform kindness, and constant willingness to facilitate 
our investigations by every means in your power. To Lieut. C. F. Roe, who commanded our 
escort from Carroll to Camp Baker, we are under obligations for many kindnesses. At Camp 
Baker, Fort Ellis, and Camp Lewis, we were the recipients of most generous hospitalities from the 
officers of those posts; and our brief delays at those points are remembered by us as being among 
the pleasantest days of the trip. 
The vertebrate fossils collected during the summer were submitted to Prof. O. C. Marsh, and 
by him identified. The invertebrates were examined by Mr. R. P. Whitfield, of Albany, and his 
identifications, with occasional comments on the specimens, will be found in the body of the report. 
A paper by Mr. Whitfield, describing such new forms as were discovered during the summer, 
accompanies our report. To both of these gentlemen our thanks are due for the many favors that 
we have received from them. 
We remain, sir, very respectfully, your obedient servants, 
Epwarp 8. DANA. 
Gro. BIRD GRINNELL. 
Col. Wu. LUDLOW, 
Chief Engincer of the Department of Dakota, 
Saint Paul, Minn. 
