A surface of erosion on metamorphic or igneous rocks below sedimentary rocks is a(n):

A surface of erosion on metamorphic or igneous rocks below sedimentary rocks is a(n):
  a. nonconformity.
  b. disconformity.
  c. angular unconformity.
  d. anticonformity.
  e. none of the above

Whose work was the basis for the principle of uniformitarianism and the unavoidable necessity of a
  great age for Earth?
  a. Charles Lyell
  b. William Smith
  c. James Hutton
  d. Lord Kelvin
  e. John Joly

Which of the following was not among the early scientific attempts to determine Earth's age?
  a. the cooling rate of a molten iron sphere of Earth's diameter
  b. the rate of sediment deposition
  c. the rate at which water precipitation accumulated in the ocean
  d. the geologic principles and the inferred rates of change necessary to explain the fossil
  record
  e. the rate of salt accumulation in the ocean

The length of time preserved in Grand Canyon rocks is about:a.
   10,000 years.
  b. 100,000 years.
  c. 1 million years.
  d. 1 billion years.
  e. 10 billion years