Discussion report using gravity readings on Onshore Northland Basin Architecture within Kea Oil and Gas Ltd Permit PEP51339. The data was a mixture of offshore and onshore data collected by Kea Oil and Gas Ltd and GNS Science during 2010 and 2011. These gravity observations combined with gas sampling data indicates that an onshore sub-basin exists which is currently producing thermogenic hydrocarbons. The main play within this area is still considered to be the Glen Massey Sandstone which is located beneath the Tikorangi Limestone.