I think it best to regard the Cement-Rockstar the test contacts. The upper line is as much little other lines that nothing positive can be made of it. The lower one certainly brings in a tremendous clearness, a sharp contact, and always a line easily recognized in good exposures. The [illegible] upper one will be more easily found in ordinary exposures. From the formation standpoint it is more practicable to begin the Lockport above the cement beds, but in structural grounds the evidence is in favor of placing the line at the base of the cement series. If a break in deposition occurred, then the gravel began with the cement series and these can be added to the Lockport for- imation.