As I was looking in an old Saint Gregory Hymnal, I just found the song with an additional verse. The melody in the hymnal is different, though, taken from Grieg, and different from the one I linked to performed by the Revellers.

THE SNOW LAY ON THE GROUND
Saint Gregory Hymnal credits lyrics to Rev. Dr. Lingard, as an Old English Carol

The snow lay on the ground
The stars shown bright
When Christ our Lord was born
On Christmas night.

Twas Mary, daughter pure
Of holy Anne
That brought into this world
The God made man.

She laid him in a stall
At Bethlehem,
The ass and oxen shared
The roof with them.

Saint Joseph, too, was by,
To tend the child,
To guard him, and protect
his mother mild.

The angels hovered 'round
And sang this song,
"Venite, adoremus Dominum."

And then that manger poor
Became a throne;
For He whom Mary bore
Was God the Son.

O come then, let us join,
The heav'nly host, To praise the Father,
Son and Holy Ghost.