Throwback Thursday: Sea to Sea, See?

Those little paw prints tracking up the sand
Along the vast Pacific's northern shore
That parallel much larger ones are grand
If none too permanent clues proving lore
That Milo Mudfoot and his hero, Jack
Were first to cross this continent entire.
Arriving on a privateer out back
And east somewhere, then, never did they tire,
They journeyed with a wagon train along
The trail to Oregon. Their masters had
Succumbed to dysentery, but this strong,
Resilient pair of pups, through good and bad,
Had made it. Now they bark at crashing waves
And have all any doggies e'er could crave!