SECTION IV.. What Is the Lowest Metamorphic Rock?

What is the lowest metamorphic rock?

Describe it.

How does mica slate differ from gneiss?

Is it well distinguished from argillaceous slate?

What is the third rock in the metamorphic series?

Why is it difficult to determine the upper limit of this series?

Why do the principal rocks of this series occur in the order here given?

What other rocks may take the place of these principal rocks?

Where do the metamorphic rocks occur?

What is their thickness and amount?