Question

1. fossils in the burgess shale are not arranged in an orderly way because

a. they were buried over different time periods
b. the mud avalanche that buried them caused the fossils to lie in a disorderly
fashion
c. the shale was composed of large chunks of rock that knocked the fossils into
different positions
d. movements in earths crust moved the fossils after they were formed

1. a shell has dissolved and left a cavity in sandstone. what type of fossil is it?

a. actual remains
b. cast
c. imprint
d. mould

1. the calcified shape of a soft-fleshed crinoid is found inside a layer of sandstone

what type of fossil is it?
a. actual remains
b. cast
c. imprint
d. mould

1. in which type of rock are most fossils found?

a. igneous
b. deciduous
c. metamorphic
d. sedimentary

1. a major life form of the cambrian period was

a. clams
b. sharks
c. trilobites
d. deciduous trees

Explanation:

• Question 4: The Burgess Shale fossils were buried by a mud avalanche, which disrupted their orderly arrangement.
• Question 5: When a shell dissolves and leaves a cavity (mould) in sandstone, it is a mould fossil.
• Question 6: A calcified shape (cast) of a soft - fleshed crinoid is a cast fossil.
• Question 7: Most fossils are found in sedimentary rock as it forms in layers and can preserve organic material.
• Question 8: Trilobites were a major life form in the Cambrian Period.

Answer:

1. B. the mud avalanche that buried them caused the fossils to lie in a disorderly fashion
2. D. mould
3. B. cast
4. D. sedimentary
5. C. trilobites