MIDLAND, Texas (AP) _ A frightened toddler trapped for more than a day 22 feet down an abandoned backyard well talked to her mother and cried Thursday as anxious rescuers pounded their way through solid rock with jackhammers.

Eighteen-month-old Jessica McClure fell into the well about 9:30 a.m. Wednesday while playing with other children at a private day-care center run by her aunt and her mother.

Midland Police Chief Richard Czech said Thursday night the rescuers had hit much harder rock than they had anticipated but that ''I'm going to guess that maybe by 6 in the morning, if the good Lord's willing, we'll be done.''

Floodlights were turned on as dusk fell Thursday. Dozens of friends and neighbors gathered to wait and pray with Jessica's parents, Chip, 18, and Reba Gayle McClure, 17. Jessica is their only child.

Earlier Thursday, Midland police Cpl. Jim White said he listened to the child through a microphone that had been lowered to her.

''The only thing I heard her say is, 'Mommy.' The rest is just crying and moaning,'' he said.

Rescue workers using hand-held hydraulic drills inside a shaft sunk 64 inches away from the abandoned well had chiseled about 40 to 50 inches through solid rock but still had about two feet to go, Midland Fire Chief James Roberts said.

''We don't have any best estimate'' on when rescuers might reach Jessica, he said. ''If you would have asked me yesterday morning early, (I would have said) we wouldn't be here today. The rock has been much harder. Nobody visualized that rock being that hard.''

An earlier, smaller pilot shaft was drilled to within six inches of the well, but the later drilling was on a shaft that is 12 to 20 inches wide, one through which a rescuer could fit, he said.

''We are just trying frantically to get to the little girl through the rock,'' Midland police Sgt. Jeff Haile said. ''The workers are starting to feel anxiety and it's combining with their fatigue.''

''At some points, it's harder than granite,'' Haile said, quoting a federal Mine Safety and Health Administration official, Dave Lilly, from Carlsbad, N.M.

Workers had drilled a shaft, with a 3-foot diameter, 28 feet deep next to the well, then began working up toward the child. Progress was slowed by solid rock that kept breaking drill bits.

Doctors at first said the child could last as long as 36 hours, or until 9:30 p.m. Thursday, but Dr. Chip Klunick, emergency room doctor at Midland Memorial Hospital, said Thursday night she could survive longer.

''If the child is not injured severely, she could probably go about four days without water,'' he said. ''She is dehydrating, but not at too extensive a rate.''

The little girl, described by an uncle as ''a fighter,'' slept during the night Wednesday after heaters were installed to blow warm air into the 8-inch- wide entrance of the well in the backyard of her aunt's house.

Jessica had not had anything to eat or drink since she tumbled into the well, and doctors at the scene considered lowering a bottle to the girl because of concerns about dehydration.

''But then we thought, we don't want to fill her stomach if she has internal injuries or is going to require surgery when she comes out,'' said Klunick. ''She could have any kind of injuries down there. We just don't know.''

Jessica remained alert Thursday afternoon. ''She's crying, she's humming, she's singing,'' Haile said.

A special microphone was dropped into the shaft to communicate with the girl, and a camera was lowered so the child's face was briefly visible.

The well, about 8 inches in diameter at the top, widens farther down until it narrows to a 6-inch opening below the spot where Jessica came to rest.

By late morning, workers had reached the casing pipe entering the well near Jessica and had switched to smaller, more precise equipment to burrow their way through. A mining expert flown in from Carlsbad, N.M., by a Midland businessman arrived at the scene with special equipment.

''The closer they get, the more vibrations, the louder the noise. The poor little thing is scared,'' said White. ''The closer we get, the more uncomfortable she is going to be but it's the only way we can go.''

Because of the narrowness of the well, workers were unable to go into the well themselves. They didn't think throwing a line to the girl would work.

''She wouldn't have the strength to hold on to anything,'' said White.

According to police, the dry well had been covered by a large rock or a flower pot, which was apparently knocked away by the children. White said such a temporary cover would be a violation of a city ordinance requiring wells to be permanently covered.

Neighborhood children said they occasionally threw rocks down the abandoned water well casing.

''I guess it 's one of those freak accidents that could probably happen to most anyone. It's something that just touches everybody's heart,'' said Carol Davis, the mother of six.

''I've known her since she was born - she's rambunctious,'' said Jessica's uncle, Tommy Johnson of Midland. ''She's a fighter.''