FORT WORTH — A mail carrier accused of fatally injuring a Yorkshire terrier with a rock in May surrendered to authorities Thursday, police reported.Ricky Eugene Jackson, 48, turned himself in at the Tarrant County Jail. Bail was set at $3,500. He posted it and was released, said Sgt. Raymond Bush, a police spokesman.An arrest warrant had been issued for Jackson on Wednesday on a felony animal cruelty charge.Police have said that Jackson was delivering mail on May 17 in the 3600 block of Hazeline Road in the Meadowbrook area when he encountered 5-year-old Maxwell, who was not on a leash and was in a yard across the street from his owners’ house. Owner Lawrence Brown told police that he heard a dog yelp and went to the front of his house. There, he confronted the mail carrier, who told him he felt threatened by the 10-pound dog and did what he had to do to protect himself.Jackson has been on paid leave from the postal service since the incident.