Marines were still in their traditional role of ship security and "sailor control
during the Civil War period and were very small in number. I think Teddy Roosevelt's time is when they started being used as an expeditionary force, heck even in World War I they were part of the Army's Second Division.
Cougar pointed out the highlight of the USMC on land in that a battalion was at First Bull Run and got routed off the field with the rest of the army. They also did some good work at Ft. Fisher in North Carolina.
I suppose the Confederate highlight for their marine corps on land actually came on Lee's retreat to Appomattox. When Richmond and Petersburg fell the sailors and marines of the James River Fleet were formed into a battalion under Commodore John Tucker (300 sailors, 200 marines). The retreat was obviously a dismal time for the Army of Northern Virginia but Tucker's Marine Battalion was a source of some comic relief for Lee's veterans, who scoffed at the navy and marine uniforms of the battalion with their seaman's caps, blue jean collars, marine shakos and bell bottomed white pants. Lee's men called them the "Aye, Ayes" because they answered every order with an "Aye, aye" or repeated every order and added an "Aye, aye" at the end. Ironically enough this good natured ribbing ended at the Battle of Sailor's (Sayler's) Creek. Sailor's Creek was a disaster for Lee in that almost all of Ewell's Corps was cut off and captured by the attacking Federals.
Tucker's men were assigned to that corps in a division commanded by Lee's son Custis. The sailors and marines were one of the few Confederate units that did not break in the initial Federal charge at Sailor's Creek. After the rest of the corps surrendered the marine battalion held out and at one point counterattacked the six Federal divisions surrounding them in the wooded area they were holding. That attack routed two Federal regiments off the battlefield. After refusing several demands to surrender and repulsing attacks, Tucker saw the hopelessness of the situation and was the last Confederate unit to surrender at Sailor's Creek. More than one Federal regimental commander commented on the stubborn and heroic defense of Tucker's men in their official report of the battle. After the war, Tucker exiled himself to Peru where he became an admiral in their navy and helped map the Amazon basin. One cool story is Tucker surrendered his sword to a Union Officer at Sailor's Creek and when he was on his death bed in 1883 at Petersburg, that former Federal officer heard about it and traveled to Tucker to present the sword back to the dying man.