Alerted by an outside TV surveillance system, deputies at the Fairfax County jail thwarted an attempt to smuggle drugs through a vent leading to a storage room, jail officials said yesterday.

Chief Deputy Sheriff M. Wayne Huggins said two young women were arrested last Saturday and charged with smuggling contraband into the jail - a felony.

Huggins said one gram of PCP, a powerful hallucinogen, half an ounce of marijuana and four tablets of the tranquilizer Valium were found in a brown paper bag that had been put in a vent on the west side of the building.

Arrested were Cathy Eskew, 21, of 2831 Fairhaven Ave., Fairfax, between Telegraph Road and N. Kings Highway south of Alexandria, and Debbie L. Elliot, 22, of 6601 Glassel Ct., also south of Alexandria. Each was released on $2,500 bond.

Huggins said that shortly before the arrests, which occurred about 9:15 p.m., Eskew had visited inmate Bruce Neely and that Elliot had attempted to visit inmate John McGee but was denied admission because she wasn't on McGee's visitation card.

Huggins said McGee, as a jail trusty, had access to the food storage room where the vent led.

Sheriff James D. Swinson said that when the recently opened jail was being planned, he asked for steel mesh to cover all vents leading to the interior of the building, but that the work was not done, apparently for budgetary reasons.

In a separate development, Patricia Ann Clark, the mother of James Clark, who was convicted yesterday in a murder-for-hire case, was arrested Monday for allegedly attempting to smuggle contraband to her son in a T-shirt among clothes she had brought to the jail for him. Huggins said.

Clark, 38, of RFD 1, Mount Holly, N.J., was also charged with a felony and released on $1,000 bond.

Huggins said the contraband included a rolled cigarette believed to contain marijuana and three unidentified pills that are being analyzed for content.

Clark received two letters last week that contained marijuana cigarettes, Huggins said. While jail authorities are not permitted to read correspondence intended for prisoners, Huggins said they can examine mail for possible contraband.

Huggins said "our information network is so thorough that we have reduced smuggling of contraband into the jail to nil."

Both Huggins and Swinson said sometimes ingenious attempts are made to smuggle drugs and other contraband to prisoners. One visitor, Swinson said, tried to give an inmate an orange that had been injected with vodka. Recently, Higgins said, the nightly check of the telephone receiver which visitors use to talk with inmates through a glass partition turned up a knife blade and file inside the handle.