In what combinations is oxygen found? What proportion of the earth's crust consists of it?

In what combinations does hydrogen occur? Nitrogen? Carbon? Sulphur?

Chlorine? Fluorine? Iron? Manganese?

How does silicium occur? Aluminium? Pota.s.sium? Sodium? Calcium?

Magnesium?

How are these elementary substances cla.s.sified? (Silicium, or silicon, has but a doubtful claim to be regarded as metallic.)

SECTION II.

What is a simple mineral? How many are known?

What are the physical properties of quartz? How are the several varieties distinguished?

What are the physical properties of felspar? Mica? Hornblende? How are its varieties distinguished? Augite? Hypersthene? Talc? How are its varieties distinguished? Serpentine? Carbonate of lime? Gypsum? Its varieties?

What other minerals are mentioned?

SECTION III.

Define the crust of the earth. Rocks.

What are the unstratified rocks?

What is the structure of granite?

How are the varieties distinguished?

What is the porphyritic structure?

Describe hypersthene rock.

What are volcanic rocks? Lava? Scoriae? Pumice-stone?

How is the vesicular structure produced?

What are volcanic breccias? Volcanic grits?

What is the composition of the trappean rocks?

What is the amygdaloidal structure?

What are the three varieties of trappean rocks, and how are they distinguished?

[Ill.u.s.tration: Fig. 1.]

Name the stratified rocks. Describe gneiss. Mica slate. Sandstone.

Conglomerate. Greensand. Describe the varieties of limestone.

What is dolomite? Of what does clay consist? Clay slate? What modifications does clay slate present? What is diluvium?

CHAPTER II.

SECTION I.

What is the primary division of rocks?

Upon what principle are the unstratified rocks divided?

Upon what principle are the stratified rocks divided?

Why are the non-fossiliferous called metamorphic rocks?

Name the four cla.s.ses of rocks.

SECTION II.

What is the most abundant plutonic rock?

How is its thickness ascertained?

What is its amount?

Where is it found?

What is its ordinary structure?

What peculiarity of structure facilitates the cleavage of granite?

[Ill.u.s.tration: Fig. 2.]

The granitic ma.s.ses are generally deep below the surface; in what other position does granite appear?

[Ill.u.s.tration: Fig. 3.]

[Ill.u.s.tration: Fig. 4.]

In what cla.s.ses of rocks are granite veins found?

Were they all produced at the same time?