You find fossil horseshoe crabs in a 100-million-year-old rock. ...

[sjones]

You find fossil horseshoe crabs in a 100-million-year-old rock. You go to the coast and see horseshoe crabs living close to the shoreline. What can the principle of uniformitarianism tell you about the environment of deposition of the ancient rock?
 
  What will be an ideal response?

Question 2

Given what you know about convection, consider how global ocean circulation must work if the deep waters in the equatorial regions are known to be cold and surface waters are warm, but the latter cool when transported to cold polar regions.
 
  What will be an ideal response?

[CourtneyCNorton]

Answer to Question 1

You can use observations of how horseshoe crabs live today (shallow-water lifestyle; move to beaches to lay eggs; etc.) to infer the ancient lifestyle and the environment of sediment deposition to form the rock that encloses the fossil.

Answer to Question 2

Surface waters are warmed by the sun. As they near the poles they cool and begin to sink, helping to displace deep water toward the surface where it warms.