| Rock Unit | Depth, Feet |
|---|---|
| Surficial Deposits and/or Gubik Formation | 43 |
| Sandstone of the Colville Group and Sagavanirktok Formation | 100 |
| Shale of the Colville Group | 1380 |
| Nanushuk Group | 2250 |
| Torok Formation | 3935 |
| Pebble shale unit | 9040 |
| Kingak Shale | 9260 |
| Sag River Sandstone | 12160 |
| Shublik Formation | 12190 |
| Fire Creek Siltstone Member of the Ivishak Formation, Sadlerochit Group | 12430 |
| Ledge Sandstone Member of the Ivishak Formation. Sadlerochit Group | 12840 |
| Kavik Member of the Ivishak Formation, Sadlerochit Group | 13285 |
| Echooka Formation, Sadlerochit Group | 13660 |
| Lisburne Group | 13985 |
| Endicott Group | 17870 |
Data Source:
Table 15.3. - Total depth and depths to selected stratigraphic horizons
for Government-drilled wells on the North Slope of Alaska., in:
Gryc, George, Ed., 1988, Geology and exploration of the National Petroleum
Reserve in Alaska, 1974 to 1982, U.S. Geological Survey Professional
Paper 1399, Pgs.322 - 324.