In connection with the transfer of the Royalty Properties to the Trust upon its formation, Sabine Corporation had reserved to itself all executive rights, including rights to execute leases and to receive bonuses and delay rentals. In January 1993, Pacific (USA)completed the sale of substantially all of Pacific (USA)s producing oil and gas assets to Hunt Oil Company. The sale did not include the executive rights relating to the Royalty Properties, and Pacific (USA)s ownership of such rights was not affected by the sale.
For the three months ended March31, 2017 and 2016, exploration expenses for continuing operations incurred were approximately $0.2 million and $0.9 million, respectively. Approximately $0.1 million of the expense incurred in 2017 was due to geological and geophysical type expenditures and the remaining $0.1 million was due to delay rentals. Approximately $0.8 million of the expense incurred in 2016 was due to two exploratory wells that were abandoned at various stages, resulting in dry hole expense and the remaining 2016 expense of $0.1 million was due to geological and geophysical type expenditures.
For the three months ended March31, 2018 and 2017, exploration expenses for continuing operations incurred were approximately $0.2 million, respectively. Approximately $0.1 million of the expense incurred in 2018 was due to geological and geophysical type expenditures and the remaining $0.1 million was due to delay rentals. Approximately $0.1 million of the expense incurred in 2017 was due to geological and geophysical type expenditures and the remaining $0.1 million was due to delay rentals.
Surface revenues increased for the three months ended June 30, 2019, as compared to the three months ended June 30, 2018, by $17,029. This is due to the receipt of lease bonuses and delay rentals. These amounts are non-recurring revenue recognized when received.