Holly's corduroys inexplicably turn a much darker color from one moment to the next after they enter Mr. Collie's cavern. They stay that way until she encounters him fetching her requested water.
The metal crossbow bolts float in the water.
A Civil War veteran would not be named "Jefferson Davis" Anything "III". Jefferson Davis became a widespread source of names only during the war, so it would take at least 40 years from the start of the war to generate a "Third."
It was never explained how Jefferson Davis Collie III got to the Land of the Lost.
Mr. Collie, a veteran of the Civil War (1861-1865), says "California is not even a state!" In fact, California achieved statehood in 1850, so Mr. Collie is quite uninformed on the geopolitics of his own time.
Mr. Collie says his cannon "Sarah" protected him at the Battles of Bull Run and Antietam. Confederate personnel referred to these battles as Manassas and Sharpsburg.