then , driven ahead by curiosity in their captured yacht under johansen 's command , the men sight a great stone pillar sticking out of the sea , and in s. latitude 47 9 ' , w. longitude 126 43 ' , come upon a coastline of mingled mud , ooze , and weedy cyclopean masonry which can be nothing less than the tangible substance of earth 's supreme terrorthe nightmare corpse-city of r'lyeh , that was built in measureless aeons behind history by the vast , loathsome shapes that seeped down from the dark stars .