Question

A geologist is studying rock layers in an old river bed, and he finds a fossil of a fish and a horsetail rush in the same rock layer. According to the law of faunal and floral succession, the geologist can assume that the rock containing the fossils may date back as far as the _____.

Cambrian period
Ordovician period
Silurian period
Devonian period

Answer 1

A geologist is studying rock layers in an old river bed, and he finds a fossil of a fish and a horsetail rush in the same rock layer. According to the law of faunal and floral succession, the geologist can assume that the rock containing the fossils may date back as far as the Devonian period.

Answer 2

The correct answer is Devonian period.

This is known to be the period of fishes which occurred 416 million years ago. It is known to be the fourth period of the Paleozoic Era. Significant events like evolution of first insects and other animals.

The Fishes evolved in the Ordovician era but the horses were found in the Devonian period only.