The Wikipedia page titled Jewish views on evolution states the following about the Netziv.
When scientists first developed the theory of evolution, this idea was seized upon by rabbis such as Naftali Zvi Yehuda Berlin, known as the Netziv, who saw Kabbalah as a way to resolve the differences between traditional readings of the Bible and modern day scientific findings. He proposed that the ancient fossils of dinosaurs were the remains of beings that perished in the previous "worlds" described in midrash and in some Kabbalistic texts. This was the view held by Rabbi Aryeh Kaplan (1934–1983).
Does anyone know where the Netziv wrote this?