Cloud Shadow

We traveled to California today, for Christmas with our girls!  I, of course, took pictures out the window of the aircraft whenever I could, which wasn't very often.  The country was covered in clouds almost completely along our route.  We were somewhere in the western part of the United States when I looked down through a clearing and saw this black shadow on the red earth.  I figured that it was a cloud shadow, but which cloud?  A little more flying and it became obvious.  I just though that this was so unusual, to see a long cloud, and its shadow on the ground