9 43 Strphodonta leavenworthiana, Hall (interior) Shaly limestone Lower Helderberg group. Indian Ladder N.Y. 44 Strphodonta leavenworthiana, Hall. Shaly limestone Lower Helderberg group. Clarksville, N.Y. 45 Strphodonta variestriata, Conrad, Lower Helderberg group. Jerusalem, Hill, N.Y. 46 Streptorhynchus woolworthanus, Hull. Lower Helderberg group. Clarksville, N.Y. 47 Leptocaelia imbricata, Hall. (12) Lower Helderberg group. Clarksville, N.Y. 48 Microdum bellistriatus, Conrad, Hamilton group. 18 Mile Creek, Erie Co, N.Y. 49 Sivalites discoidens, Hall. (shaving outline of aperture) uniangularis Hamilton group. Hamburg, N.Y. 50 Spirifera fimbriata, Conrad. Hamilton group. Hamburg, N.Y. 51 Orthoceras aesea, Hull. Hamilton group. Hamburg N.Y. 52 Grammysis arcuata, Conrad, Hamilton group. Hamburg, N.Y. 53 Modiomorpha subulata, Conrad, Hamilton group. 18 Mile creek, N.Y. 54 Etonia medialis, Vanuxem. Shaly limestone Lower Helderberg group. Clarksville, N.Y. 55 Platyceras platystomason. alveata, Hall. Shaly limestone (2 Lower Helderberg group. Clarksville, N.Y. 56 Platyceras platystoma, Hall. Shaly limestone Lower Helderberg group. Clarksville, N.Y.