The SDF or Stratigraphic Data Files are a collection of paper drill records from thoughout Pennyslvania organized by 7.5 minute quadrangle. It is a prime source of subsurface lithology. Portions have been entered into the USGS NCRDS database.
This is a Topo/geo resource which does not belong to any one staff member.
The last estimate of the collection was 31,500 done is 1987. A better estimate is currently underway. The main use for the collection is in-house reference and research by PaGS staff.