23 141 Acidaspis hamata, Conrad Shaly limestone Lower Helderberg group. Clarksville, N.Y. 142 Acidaspis hamata, Conrad Shaly limestone Lower Helderberg group. Clarksville, N.Y. 143 Acidaspis hamata, Conrad Shaly limestone Lower Helderberg group. Clarksville N.Y. 144 Orthoceras marcellense, Vanuxem. lower beds, Hamilton group. Hamburg, N.Y.- 145 Pentamerus galeatus, Dalman. Former Pentamerus, Lower Helderberg group. Indian Ladder N.Y. 146 Discina discus Hall attached to Stephodonta becki, Hall. Shaly limestone, Lower Helderberg group. Clarksville. 147 Discina discus, Hull. Shaly limestone Lower Helderberg group. Clarksville, N.Y. 148 Goniophora hamiltonensis, Hull, Hamilton group & Kaneates Lake, N.Y. 149 Palaeonilo tenistriata, Hull, Hamilton group. 1/8 Mile Creek N.Y. 150 Palaeonilo tenistriata, Hull. Hamilton group, Pratt's Falls, N.Y. 151 Aviculopecten Leabridus, Hall. (right valve) Hamilton group. Pratt's Falls, N.Y. 152 Modiomurpha mytiloides Conrad, Hamilton group. Pratt's Falls. N.Y 153 Gyroceras undulatum, Vanuxem. Upper Helderberg group. Schoharie, N.Y. 154 Tentaculites elongatus, Hall. Shaly limestone Lower Helderberg group. Clarksville N.Y.