You are given two volcanic rock samples; one is said to have been ...

[olgavictoria]

You are given two volcanic rock samples; one is said to have been ripped from the walls of the volcano, and the other is a cooled sample from a molten river. How can you tell which is which?
 
  What will be an ideal response?

Question 2

How would a Neptunist explain the layers of rock made during the formation of the Earth?
 
  What will be an ideal response?

[makaylafy]

Answer to Question 1

Answer: Both samples are composed of the same minerals. However, the fragment from the wall of the volcano is the sample with minerals readily visible to the naked eye. It is very difficult to see what composes cooled volcanic rock, so the sample with a few visible crystals surrounded by a black, nondescript background would be the cooled rock from the molten river.

Answer to Question 2

Answer: Neptunists envisioned concentric shells of different types of rocks and minerals that precipitated in sequence from a primordial ocean solution that was extremely rich in dissolved materials. In his vision, the interior of the planet was cold, and volcanoes were rare, relatively recent phenomena related to the natural burning of subterranean coal beds. So, the bottom layer was believed to be thick, massive, mostly unlayered rocks, whose bottoms were never exposed to view, Primitive Rocks. These rocks formed, according to Neptunists, by precipitation and settling of the least-soluble silicate minerals before dry land appeared. The Primitive Rocks are overlain by the so-called Stratified Formations, distinctively layered rocks composed of precipitates of more-soluble minerals mixed in places with fragments worn from highlands of Primitive Rocks, which were gradually exposed as the enclosing ocean diminished in depth.