The waters draining the lake carved out the Zongo Gut, which cuts through a chain of hills that extends from east to west.

[3] The banks of the river in this section when Van Gele visited in 1887 were bordered by gentle slopes with alternating woods, plains, maize fields and banana plantations.

[2] An expedition under Van Gèle left Equateur Station on 26 October 1887 in the steamer En Avant towing a large canoe that could hold 100 people.

[2] In 1889 Van Gèle and Georges Le Marinel studied the north shore of the Ubangi between Banzyville and Mokoangai and discovered the mouths of the Kuanga and Benghi rivers.

[5] Louis Royaux (born 1866) joined the Congo Free State in 1892 and became the deputy of Florent-François-Marie Heymans in Zongo.