The spot on top of brown and white puppy highly desirable.It is the thumb print of lady Blenheim. In the 18 century Lord Blenheim was in battle with the french. hIs wife was very nervous about him in battle, she had a pregnant cavalier on her lap for comfort, she would nervously press her thumb on top of dogs head while waiting for news of her husband. When news came her husband was alive and won the battle, the Cavalier gave birth all puppies having the mark from lady blenheims thumb