The name MacAskill is of Norse origin. The ancient Norse name "Askell" is the source. Up until a couple of generations ago my family spelled the name "MacAskell". It is a small step to "Haskell". The MacAskills were known collectively as "Clan Tasgaill". I saw someone in a census called "Taskell MacAskill", so it is quite easy to see how "Haskell" could have come about.