Which type of rock underlies the region surrounding Niagara Cave?

The correct answer is sedimentary rock, as this type of rock is formed from the accumulation and lithification of mineral and organic particles, often in water environments. In the case of Niagara Cave, the surrounding region is characterized by sedimentary deposits primarily made up of limestone, which is a key feature of many cave systems. The limestone was formed from ancient marine environments where sediments, made up of calcium carbonate from shells and corals, accumulated over time. This geological background contributes to the unique formations and features found within the cave itself, including stalactites and stalagmites, which are indicators of a sedimentary rock formation due to the dissolution and precipitation processes involved.