What conditions must exist together, in the force by which continents are produced?
What cause fulfils these conditions?
What is the proof that the temperature under given localities is variable?
What will be the result of these variations?
What is the law of expansion of rocks, as obtained by experiment?
What amount of change of level may be thus accounted for?
What circumstances would probably increase this amount?
What amount of vertical movement must be accounted for?
Why must these changes of level be very slow?