Middle ear to sounds of higher frequency, because these are better taken up by the inner ear (which also responds to higher frequencies than those of non-mammals). The malleus, or "hammer", evolved from the articular bone of the lower jaw, and the incus, or "anvil", from the quadrate. In other vertebrates, these bones form the primary jaw joint, but the expansion of the dentary bone in mammals led to the evolution of an entirely new jaw joint, freeing up the old joint to become part of the ear. For a period of time, both jaw joints existed together, one medially and one
Anvil firing trail. The top anvil is placed upside down, face to face with the bottom anvil. Anvil firing was once commonly performed in the Southern United States as a substitute for fireworks during celebrations. One such noteworthy celebration was held on the day the state of Texas voted to secede from the Union. On February 23, 1861, Texas Ranger and prominent Union supporter, Thomas Lopton Campbell Jr., was held captive and forced to "fire the anvils" in the streets of Austin. Anvils were also traditionally fired on St. Clement's Day, honoring Pope Clement I, the patron saint of blacksmiths and metalworkers.