El Paso country in Texas was ravaged by which struggle between 1866 to 1877?

The Salt War
The El Paso Salt War began in the late 1860's as a struggle between El Paso businessmen W.W. Mills, Albert J. Fountain, and Louis Cardis in an attempt to acquire title to the salt deposits near the base of the Guadalupe Mountains. Mexican Americans of the valley communities, who had for years collected salt there for free, were now faced with the threat of being charged salt collection fees.

Mills filed his own claims to the salt beds and formed a group that became known as the Salt Ring. Fountain, who had a falling out with Mills, later became the leader of the opposing Anti Salt Ring. He was elected to the Texas Senate with the expectation of securing title to the salt deposits for the people of the El Paso area. Cardis and Mills soon joined forces with Charles Howard, a Missouri lawyer. Cardis helped secure Howard's election to district attorney, but later became bitter enemies with him after Howard filed on the salt lakes for himself. These actions outraged Mexican citizens who considered the lakes public property under the terms of the Treaty of Guadalupe Hidalgo. Cardis later joined forces with Father Antonio Borrajos, an Italian priest who served the Mexican communities, to oppose Howard.

In September 1877, Howard started a riot when he arrested two San Elizario residents who attempted to go for salt. An angry mob captured and held Howard for three days at San Elizario. He finally gained his freedom by vowing to give up claim to the salt beds and leave the country. He retreated to Mesilla, New Mexico, but quickly returned to murder Cardis in an El Paso store. Angry Mexicans demanded Howard's arrest. Howard was arraigned for Cardis' murder and placed under bond to appear in court in March.

In early December, a wagon train of Mexicans from both sides of the border left the valley, headed for the salt lakes. Howard brought suit and left for San Elizario to press charges. In San Elizario, he and a handful of Texas Rangers were besieged by an angry mob and held up for four days in the rangers' fort. On the fifth day Howard gave himself up. The rangers also surrendered, believing that Howard was to be freed. On December 17th, Howard, his agent John E. McBride, and John G. Atkinson were shot by a firing squad composed of Mexicans. The rangers from the fort were allowed to leave after forfeiting their arms.