Answers to Second Laboratory Pre-test

Rock-units are generally identified by color and letter symbol.  The first letter of the letter symbol gives the age, according to the Geologic timescale, the second (or third) letter describes the rock unit. Colors can be roughly used to infer the age of the rocks as well. Triassic-age rocks, for example, should be colored in shades of bluish green (peacock green - as the code states), but exceptions are possible.

(2 points)
In the Connecticut valley, the geological map of Connecticut does not strictly follow this coloring scheme (rocks are tan, to pinkish brown) because the greens and blues have already been used up for other rock units (of Triassic age) elsewhere in the state.

(1 point)

we identified two rocks last week:

a brownish-red, layered rock, very brittle in parts, some shiny minerals on the surface

a dark gray, massive rock, with no layering.

(2 points)