Yesterday, some of the seafloor cores had manganese nodules in them. Nodules are round looking rocks found on the seafloor in many parts of the Pacific Ocean. They have a lot of the chemical manganese in them along with other metals. Scientists believe that they form when something on the seafloor, like a fish tooth for example, becomes coated with chemicals that come out of the ocean water. The chemical layers keep coating the outside until the nodule can become quite large. In the photo below, you can easily seen the ring shape. The diameter of the one in the photo, with me, is about 7 cm. Now you can see about how large good old JR is. Look below for more photos.