A column of Marines under Colonel Joseph H. Pendleton marched toward Santiago de los Caballeros, where rebel forces had established a government. Along the way, Dominicans tore up the railroad tracks, forcing Marines to walk. They also burned bridges, delaying the march. Twenty-four miles into the march, the Marines encountered Las Trencheras, two fortified ridges the Dominicans had long thought invulnerable: the Spanish had been defeated there in 1864. At 08:00 hours on June 27, Pendleton ordered his artillery to pound the ridgeline. Machine guns offered covering fire. A bayonet attack cleared the first ridge. Rifle fire removed the rebels who were threatening from atop the second. The significance of this battle lies in the fact that this was the first experience of Marines advancing with the support of modern artillery and machine guns.