of years, forming submerged deposits several ...
of years, forming submerged deposits several feet thick. during the last ice age, sea levels dropped, exposing these shell layers to air and rain. eventually, the shell became covered with soil, then trees and other vegetation. rainwater percolating through the dead vegetation and soil picked up carbon dioxide and became carbonic acid, the same ingredient that makes soda fizz. (3) as this weak acid soaked downward, it dissolved some of the calcium in the shells, producing calcium carbonate, which solidified in lower layers, much like how flowstone and stalactites are formed in caves. this material “glued” the shell fragments together into a porous type of limestone we now call coquina, which is spanish for “tiny shell.” a stronger fort is needed (4) although found in very few places in the world, conditions were just right for coquina formation along the east coast of florida. the spanish knew about this rock, and while they might have picked up loose chunks, the people of st. augustine were primarily soldiers, not stonemasons, and so this rock sat mostly unused and unappreciated for 4 select the correct answer. based on paragraph 3, what is true about calcium carbonate? a. it solidifies when placed in caves. b. it helps bond materials together. c. it dissolves calcium in shells. d. it is made from limestone. reset next