
          Rec. Nov. 18

Washington D.C. Nov. 16th 1842

Sir

I transmit to you by today's Cars a Collection
of Plants which I have made during the
present year in the course of a Geographical
Exploration to the Rocky Mountains. The region
over which the collection was made, extends
from the 39th to the 43rd degree of North
Latitude & from about the 95th to the 112th
degree West Longitude. The labels which are
affixed to the plants will enable us to assign
them their exact localities on a Topographical
Map of the Country which I am now engaged
in constructing, based upon numerous
Astronomical positions, & the Barometrical
observations which I succeeded in to the top
of the Mountains, will give us their limits.
In their present state I am afraid you will
find it almost impossible to fix localities
from the labels & I regret that I have
no means at present to render them
more clear.

I think that you will already
        