Interesting folding postcard with the cover picturing the members of the Chicago White Sox on the Denver/Rio Grande Railroad, posed at Glenwood Springs, CO.  The fold-out explains that the team was on the way to spring training in Paso Robles, CA, but stopping in San Francisco en route at the invitation of the president of the Panama-Pacific International Exposition.  The postcard contains two images of the team, the back side of which has its stamp cut away and significant glue stains and paper remnants clearly visible on the reverse, from scrapbook mounting.  The postcard originates from the estate of Shoeless Joe Jackson, to whom the card is addressed (though only part of his name and address is visible due to the paper remnants).  Postmarked Denver, Colorado in 1915.  What is interesting is that Jackson did not become a member of the White Sox until August of 1915, well after Spring Training.  Though Jackson had, that Spring, threatened to quit baseball in favor of a vaudeville career, he wound up returning to Cleveland to start the season and played in 83 games for the Indians.  An interesting postcard originating from Jackson's estate, depicting his future team.