Elsewhere's Exclusive Quiz for the day: What do areas outside of Bloomington, Indiana have in common with the areas outside of San Juan, Puerto Rico?
The third important physiographic feature is the karst region in the north. This area consists of formations of rugged volcanic rock dissolved by water throughout the geological ages. This limestone region is an extremely attractive zone of extensive mogotes or haystack hills, sinkholes, caves, limestone cliffs, and other karst features. The karst belt extends from Aguadilla, in the west, to a minor haystack hills formation in Loíza, just east of San Juan.