Baculites compressus. Say, from the Cretaceous of the South Dakota. 1. A young shell preserving the early coils. The living chamber occupied about one half the length of the shell. 2. A specimen of the same size as the last but with the outer shell broken away revealing the sutures - the outer edges of the septa. Note the variations in the sutures from the apex of the shell 2 to its wide end and on through the progressively layer shells as shown in 3, 4, 5, and 6, which represents the condition of the suture in the adult shell.