While they were eating, Nancy and her friends discussed how they were going to get across the water. They did not want to risk being trapped in midstream if the truck stalled.

"Let's follow the water upstream," Ned suggested. "We may come to a shallow place. We could cross there and then drive back to follow the direction of the arrow."

They started off but found the going a bit difficult. What had been a wagon road was now overgrown with gra.s.s and bushes. The truck was st.u.r.dy, however, and finally they came to a shallow part of the stream.

Nancy laughed. "I wonder if Clem knew about this road, but was in too much of a hurry to take this longer way."

She described the spill which she, Julie Anne, and Clem had taken when the farmer's old car had tipped over in the water.

When they reached the second hollow oak with the plate, Ned looked skeptically at the terrain due south. "We'd better not try taking this truck through those woods. I'm sure there's not enough s.p.a.ce between the trees."

The whole group climbed out and waited for Nancy to lead the way. Everyone kept looking for hollow oaks, but found none. Finally they climbed to the top of a wooded ridge.

"Isn't that an old oak tree ahead of us?" George asked.

"It looks like one," Nancy replied. The six searchers hurried forward.

As they neared the tree, Ned remarked, "Somebody has mutilated this."

"But why?" Burt queried. "There's no lead plate on it and the tree looks pretty st.u.r.dy to me, not like one with a hollow center."

There was no doubt but that someone with a hatchet had hacked at the oak over and over again to get to the middle of it.

"The man who did this," said Burt, "must have thought it was the prize one."

"What a shame to damage it!" Bess said. "This was a gorgeous tree. Nancy, do you think the person who hacked the trunk has anything to do with the mystery?"

The young detective shrugged. "I'm not sure. He could have."

George spoke up. "If it was Kadle or his buddies they're probably getting so desperate to find the treasure that they'll hack any big oak."

Nancy wondered if the State Police had picked up Kadle or had any leads on him. She decided that before they returned to the dig she would go to Walmsley and find out whether there were any new developments.

The group trudged on down the side of the hill. According to the sun they were still going due south. Ahead was open farmland with a stretch of woods beyond. As they stumbled along over the uneven ground, Bess suddenly gave a cry and went down in a heap.

"Oh!" she exclaimed.

"What happened?" Dave asked, running to help her up.

"I stepped on a stone that moved," she said. "For a few seconds I thought I'd sprained my ankle, but it's okay." She stood up.

The others had come to see what had happened. Nancy, relieved to know her friend was all right, glanced down at the stone which had rocked under Bess's foot. Noting the odd shape, she picked it up and brushed off the dirt.

"It's a spearhead!" she exclaimed.

The others gathered closer to examine it.

"That looks like an old Indian relic," Dave remarked.

"I wonder," Nancy thought, "if someone put this on the ground to indicate a direction."

She decided it would be pure coincidence for the discovery to be a.s.sociated with her mystery. But Nancy's detective instincts led her to hunt for more spearheads. A little farther on were a row of them. She pointed out her find to the others.

"They certainly mean something," Ned remarked. "And they all lead the same way."

"But," Burt objected," they couldn't possibly be directions to the hollow oak with the message in it. I think someone has put them here fairly recently."

"Why do you say that?" Bess asked.

"Because they're in such a neat line. If they'd been here for any length of time they'd have been disturbed by animals or people. Some would be missing, probably, or kicked out of order."

Nancy nodded. "Yes, I think so too."

All the young people wondered where the weaponheads had come from and who had placed them here. Suddenly into Nancy's mind sprang an image of Bob Snell. Could he possibly have done this, hoping that someone would find them and go the way they pointed? She was skeptical of this, however, telling herself Bob's abductors surely would not have given him time to place them.

She and her friends followed the spearheads for a few minutes. There were no clues to the missing student's whereabouts, nor to a hollow oak.

Nancy noticed that Bess was limping a bit and said they should go back. On the way she picked up three of the spearheads, while asking Bess, "Can you walk as far as the truck?"

"Oh yes," Bess replied. "But I'll be glad to get on level ground again!"

The boys helped her hop on the good foot and finally they all reached the truck. Nancy said she wanted to stop in Walmsley and telephone the State Police. She was not sure of the right direction, but she made a good guess and after a while they rode into town.

She called the police and told them about the spearheads. They were interested in her story and said they too would search the area.

"Incidentally n.o.body has come to that house where you found Mr. Armstrong. We think Kadle abandoned him or one of the gang was watching the place from the woods when Mr. Armstrong was taken away. If so, those kidnappers will not show up again in Elizabethtown."

"Maybe you'll have better news the next time I call," Nancy said.

She rejoined her friends and told them the discouraging news. Bess said, "Then this means, Nancy, that you're still in great danger."

The young sleuth smiled. "How could I be harmed with all of you around?"

When they arrived at the dig, the searchers found the young archaeologists jubilant. Art and Julie Anne together had unearthed the skeleton of a very important person.

"We think," said Theresa, "that he was probably the chief of the tribe. Others near him were no doubt his family and possibly they all were killed in a war. The chief's brain had been pierced by an arrow."

"How do you know he was the chief?" asked Dave.

"Because there was a fine antler headdress near his skull. Such a decoration was worn by an important man."

"This is exciting," Nancy said. "What a lot you did here today! I also have something for your exhibit." She took the spearheads from her pocket, and explained where they had been found.

"These are fine specimens," Theresa said. "I believe they're Hopewell work."

Nancy noticed that Bess had not waited to take part in the celebration. She had gone into the house immediately. Nancy and George headed for the cousins' room. Bess was not there.

"Let's find her," George proposed. She and Nancy went into the large old-fashioned kitchen. Bess, wearing a big ap.r.o.n, was preparing supper.