Punta Mar Chuiquita, Puerto Rico. Punta Mar Chuiquita, is a beach region located in the north coast of Puerto Rico protected by rocks and vegetation. A combination of marine ecosystems, sand and gravel beaches, dunes, Pleistocene eolianites, limestone rocks, and beachrocks make up this unique coastal landscape of the Puerto Rican archipelago. These barriers act as the first line of defense on this Caribbean coast against the effects of wave impact and erosion processes. The eolianites were originally deposited as sand dunes and are composed of clasts of calcareous origin and terrigenous material (e.g., quartz). They became fossilized by early cementation processes, in which calcium carbonate is the main cementing agent. As a result of this process, sedimentary structures such as cross-stratification, marine fossils, and ichnofossils have been preserved in these rocks. Beachrocks occur parallel to the shoreline and perpendicular to the beach profile. Their exposure is becoming a frequent phenomenon due to increased coastal erosion. (Photograph taken in September 2021 by Kevián Augusto Pérez Valentín, University of Puerto Rico, Río Piedras Campus, Punta Mar Chuiquita, Manatí, Puerto Rico.)