Actinoceras

It is an ancient marine organism belonging to the subclass Nautilus in the order Cephalopoda, and its fossils are mainly found in the Ordovician strata. One of its prominent features is that the outer shell is straight and the body tube is prominent, with flat and wide body tube sections resembling beads. The structure of the neighboring wall is complex, with the neck of the neighboring wall bending outward at an angle of approximately 45 degrees. There is calcium filling inside the body tube, which is an important basis for paleontologists to study its classification and evolution. Widely distributed, it has been found in Asia and North America, especially in the Ordovician strata of northern China. Understanding ancient marine ecosystems and geographical environments holds significant scientific value.