Only part of "Long Time Ago" by George Pope Morris is given in the lyrics posted by Vissjoy, from Copland's arrangement. Here is the original from Morris's collected poems (this one pub. 1840).

LONG TIME AGO

Near the lake where drooped the willow
Long time ago!
Where the rock threw back the billow
brighter than snow.
Dwelt a maid, beloved and cherished
By high and low;
But with autumn leaf she perished
Long time ago!

Rock and tree and flowing water,
Long time ago!
Bee and bird and blossom taught her
Love's spell to know!
While to my fond words she listened
Murmuring low,
Tenderly her dove-eyes glistened
Long time ago!

Mingled were our hearts forever,
Long time ago!
Can I now forget her? - Never!
No - lost one - No!
To her grave these tears are given, given
Ever to flow:
She's the star I missed from Heaven
Long time ago!

From the small fragment of the music given at the American Memory site, to me it seems unlikely that the "Daddy" Rice minstrel tune for his "Long Time Ago" (Shinbone Alley) is the tune used for the Morris poem. Rice When you reach this site scroll down to the paragraph headed "Pursuing Artistic Freedom--Early Published Music...; then click on the portrait to the right and the page with a fragment of the music will come up. (The 2nd paragraph with remarks about "Near the Lake..." as a republication with new lyrics is incorrect)
For words similar to Rice's Long Time Ago (Shinbone Alley) see thread 43912: Here