Quote 82
"The great wall of vegetation, an exuberant and entangled mass of trunks, branches, leaves, boughs, festoons, motionless in the moonlight, was like a rioting invasion of soundless life, a rolling wave of plants, piled up, crested, ready to topple over the creek, to sweep every little man of us out of his little existence. And it moved not." (1.70)
Nature is a living, silent, immobile, and malevolent mass: we're thinking that Marlow knew about kudzu.
Quote 83
"Trees, trees, millions of trees, massive, immense, running up high; and at their foot, hugging the bank against the stream, crept the little begrimed steamboat, like a sluggish beetle crawling on the floor of a lofty portico. It made you feel very small, very lost, and yet it was not altogether depressing, that feeling. After all, if you were small, the grimy beetle crawled on—which was just what you wanted it to do." (2.7)
Though it would be understandable for Marlow to feel overwhelmed by his smallness, he twists his situation rather optimistically, saying that while a beetle is small, it still crawls towards its destination. Um, okay. And we're still going to smash it with our shoe.
Quote 84
"The earth seemed unearthly. We are accustomed to look upon the shackled form of a conquered monster, but there - there you could look at a thing monstrous and free." (2.8)
The earth is compared to an unchained monster, giving it the feel of an alien evil. Like a Predator.