"What do you make of these, Lassen?" he asked, pointing to a row of horizontal striations in the rock. The volcanologist studied them.
"They might be water marks but if so they are different from any that I have seen before," he said doubtfully. "It looks as though some force had cut the rock away in one sharp stroke."
"Exactly. Notice this yellow powder on the ridges. Water would have washed it away."
Dr. Bird stepped forward to the wall and idly attempted to pick up a pinch of the yellow powder he had referred to in his fingers. He gave an exclamation of surprise as he did so. The powder was evidently fast to the wall. He drew his knife from his pocket and pried at the stuff. It fell readily. He scraped again and caught a speck of the falling powder in his hand. He gave a cry of surprise, for his hand sank as though borne down by a heavy weight. With an effort he lifted his hand and examined the substance.
"Come here, Carnes," he said. "Hold your hand up to catch some of this powder as I scrape it off."
he detective held up his hand. Dr. Bird pried with his knife and a shower of dull yellow particles fell. Carnes' hand sank as though the bits of dust had been a lead bar. He placed his other hand under it and with an effort lifted both hands up a few inches.
"What on earth is this stuff, Doctor?" he cried. "It's as heavy as lead."
"It's a great deal heavier than lead, Carnesy, old dear. I don't know what it is. I am inclined to think you did a wise thing when you sent for me. Lassen, take a look at this stuff. Did you ever run into anything like it?"