A few minor amendments to represent how I remember the song as sung by Jack himself:

O yince I thocht the morning sun was brighter than the e'en
As it roused the glen and warmed the earth and nestled every gean
But it faded in the warmth o' the brightes sight I've seen
Ma bonnie bonnie lassie o the morning
And the sparkle o her laughter ever after I'll reca'
Like the trinklin linkin jinklin as the mountain burns fa'
But the hills are empty noo, the bonnie lassie she's awa
The bonnie bonnie lassie o the morning

The morning breathed oot cool as mile for mile we gaed on
Reaching for yon high high lands wi secret nooks and loans
Where the rocks were worn and weathered by the freens we'd never known
Together wi the lassie o the morning
Owre the clouds intae the sun we scrambled tae the cairn above
While the ravens soared belowus and the silent words we'd have
Then the hills threw oot their airms and gaithered us intae their love
And ma ain love for the lassie o the morning"

Then doon the scree we skipped trundling happy on the heel,
We'd fa' an laugh and see oorsels, as weans once mair we'd feel,
And we baith knew we had grasped a joy that nane could share or steal,
As I held ma bonny lassie o' the mornin.
And a dyke across the burn we built tae try tae haud its race,
But we micht has well hae tried tae haud oor wild love in one place,
Then I saw the look o' the parting, soon tae come, cloud ower the face,
O ma bonny bonny lassie o' the morning.

Bane-wearie wi' one last daft run we jostled tae the inn,
Trippin' , grippin, slippin' seeing wha'd be left ahint,
Then a gratefu' gasp o' ale, thankfu' for the day just din,
And ma ane thanks tae the lassie o' the morning.
A' thro' the dusk we lingered wi' nae words for us tae say.
Nae lang fareweel, 'twould break the spell we'd baith mind a' oor days,
Just a look, a kiss, a touch, we turned and walked away,
And noo there'll never be another morning.