One of the few early commandants not to die in office, Jacob Zeilin resigned and Charles McCawley took over the post.
He was born in Philadephia, thats right another Philadelphian. He joined the Marine Corps just in time to serve in the Mexican War. He was at the storming of Chapultepec and also when Mexico City was taken. During the Civil War, he took part in several attacks including an attack on Fort Sumter, which failed quite terribly. However, McCawley received a promotion to major.
Do to the change in rank, McCawley became a colonel on acheiving the post of commandant. During his time, McCawley tried to achieve better training and better officers. Also he created a clothing factory in Philadelphia that would only serve Marines, providing them with cheap clothing. Following the new tradition established by Zeilin, he retired instead of dying in office.
Information for this node was taken from http://hqinet001.hqmc.usmc.mil/HD/Historical/Frequently_Requested/Commandants.htm and The United States Marines : A History which sits on my bookshelf.