Helderberg Formation. In North America a division of the Silurian strata is called (after the Helderberg Range, in the east of New York state) the Lower Helderberg formation. It appears to be on the horizon of the English Ludlow beds. The Upper Helderberg formation of North America is a member of the Lower Devonian strata.
Helderberg Formation.
Chambers's Encyclopaedia, Volume 5: Friday to Humanitarians, p. 626
Source scan(s): p. 0641