All structures were made of limestone blocks with no visible mortar binding them together. (magnumbelize.com)
Once built with large limestone blocks the castle's appeal is mostly down, but still worth visiting to check out lovely views from the observation deck at the top. (mindthetravel.com)
His supervisor, Philip Gingerich, had collected some large fossil - rich limestone blocks from the Bighorn basin in Wyoming and brought them back to the museum at the University of Michigan. (newscientist.com)