Answer:
The area must have been on land
Step-by-step explanation:
Ferns are vascular plants that produces no seeds but reproduce by their spores. They are usually land dwelling plants. Ferns are numerous flowerless and seedless vascular plants having true roots.
Sedimentary rocks usually form as a result of the accumulation of sediments within basins of their deposition. If one encounters fossils of ferns in sedimentary layer, it implies that the sediments must have been brought from land or the area where the sediments were deposited was on land.