How does John Steinbeck use imagery in The Log from the Sea of Cortez?

Imagery:

"For the ocean, deep and black in its depths, is like the low dark levels of our minds in which the dream symbols incubate and sometimes rise up to sight like the Old Man of the Sea. And even if the symbol vision be horrible, it is there and it is ours. An ocean without its unnamed monsters would be like a completely dreamless sleep."

".... the world is furrowed and cut, torn and blasted by man. Its flora has been swept away and changed; its mountains torn down by man; its flat lands littered by the debris of his living."