These guns were fired directly at the enemy, while mortars and howitzers were lobbed over the enemy and would drop on top of them.
Civil War Cannons: Howitzers
Howitzers used during the Civil War were short barreled cannons usually made of bronze. They looked like standard artillery pieces just with a short barrel. They fired projectiles at a high trajectory lobbing shells over the heads of the enemy. Civil War howitzers were used primarily against fortifications or lobbed into masses of entrenched enemy troops.