This text comes from The Canadian Soldiers' Song Book, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
I have heard the mavis singing,
His love song to the morn;
I have seen the dewdrops clinging
To the rose just newly born;
But a sweeter song has cheered me,
At the ev'ning gentle close,
And I've seen an eye still brighter
Than the dewdrop on the rose;
'Twas they voice, my gentle Mary,
And thine artless winning smile,
That made this world an Eden,
Bonnie Mary of Argyle.
Tho' thy voice may lose its sweetness,
And thine eye its brightness too
Tho' thy step may lose its fleetness,
And thy hair its sunny hue,
Still to me thou wilt be dearer
Than all the world shall own
I have loved thee for thy beauty
But not for that alone
I have watch'd thy heart, dear Mary,
And its goodness was the wile
That has made thee mine for ever
Bonnie Mary of Argyle.