Grant's long and vulnerable railroad supply line to Holly Springs originated in Columbus, Kentucky, and ran south along the Mobile and Ohio and Mississippi Central railroads. On December 19, 1862, Brigadier General Nathan B. Forrest's Confederate cavalry struck the Mobile and Ohio Railroad at Jackson, Tennessee, then rode northward destroying it at numerous points. Meanwhile, General Pemberton sought to disrupt Grant's supply line by striking the supply depot at Holly Springs. On December 15, Pemberton secretly placed Major General Earl Van Dorn in command of a newly organized cavalry division of three brigades: Lieutenant Colonel John S. Griffith's 1,500 Texans, Colonel William H. Jackson's 1,200 Tennesseans, and Colonel Robert McCulloch's 800 Missourians and Mississippians. On December 16, Van Dorn's troopers rode eastward from Grenada, turned north toward Pontotoc after passing Cherry Hill, and near Ripley turned west toward Holly Springs. At dawn on December 20, they charged into Holly Springs and surprised, captured, and paroled 1,500 Federals and their commander, Colonel Robert C. Murphy. They emptied a huge quantity of rations, clothing, arms, and munitions from the buildings around the town square and burned them in the streets, and because time was critical, Van Dorn ordered many supply-filled buildings burned as well. Within a few hours, Grant's forward supply depot and much of the town were reduced to ashes. With his supply lines in shambles, Grant abandoned his march south, Sherman's amphibious attack down the Mississippi went unsupported, and Pemberton thwarted Grant's first attempt at Vicksburg after Sherman lost 1,776 men in defeat at Chickasaw Bayou on December 27-29.