Verse above should appear:

These blues are so blue, they are the coal black blues,
These blues are so blue, they are the coal black blues.
For my place will cave in and my life I will lose.

The Stripling Brothers did a song titled Coal Mine Blues in 1929. It's apparently a different song.

Cowboy Jack Laws B24: was first published in the 1928 Songs of the Open Range. It was recorded three times in 1929 first by Marc Williams for Brunswick. Clearly the Carter's version is a slight rewrite of an existing song.

COWBOY JACK
Carter Family- Original

He was just a lonely cowboy
With a heart so brave and true
He learned to love a maiden
With eyes of heaven's own blue

They learned to love each other
And named their wedding day
When a quarrel came between them
And Jack, he rode away

         [INSTRUMENTAL BREAK]

He joined a band of cowboys
And tried to forget her name
But out on the lonely pa-rairie
She waits for him the same

One night when work was finished
Just at the close of day
Someone said, sing a song, Jack
We'll drive those cares away

When Jack began his singing
His mind did wander back
For he sang of a maiden
Who waited for her Jack

         [INSTRUMENTAL BREAK]

When he reached the prairie
He found a new-made mound
His friends they sadly told him
They laid his loved one down

They said as she was dying
She breathed her sweetheart's name
And asked them with her last breath
To tell him when he came

Your sweetheart waits for you, Jack
Your sweetheart waits for you
Out on the lonely prairie
Where the skies are always blue