If I can prepare anything upon that subject prior to the appearance of the work, I shall be happy to do it." _Geological Survey of Dutchess County_ .-- Dr.Benjamin Allen, of Hyde Park, writes to me (June 4th) on this subject, urging me to undertake the survey; but the necessity of closing my engagements in the West rendered it impossible.
_Expedition of_ 1820 .-- Dr.Mitchell furnishes me opinions upon some of the scientific objects collected by me and my associates in the north-west in 1820:-- "The Squirrel sent by General Cass is a species not heretofore described, and has been named by Dr.Mitchell the _federation squirrel_, or _sciurus tredecem striatus_.
"The Pouched Rat, or _mus bursarius_, has been seen but once in Europe.
This was a specimen sent to the British Museum from Canada, and described by Dr.Shaw.But its existence is rather questioned by Charles Cuvier.
"Both animals have been described and the descriptions published in the 21st Vol.

of the _Medical Repository_ of New York, p.

248 _et seq_.

The specimens are both preserved in my museum.

Drawings have been executed by the distinguished artist Milbert, and forwarded by him at my request to the administrators of the King's Museum, at Paris, of which he is a corresponding member.