How does Philip Jose Farmer use imagery in To Your Scattered Bodies Go; a Science Fiction Novel?

Imagery:

"He tried to sit up and felt, numbly, a panic. There was nothing to sit up upon because he was hanging in nothingness."

"They started down the hills, pushing through the grass and carrying their grails, chert weapons, bamboo spears, and buckets."

"On the way back to the hills, he looked behind him. The dim white figure of Goring was slowly sinking into the black-and-silver waters of The River."