CHAPTER 9. ON THE IMPERFECTION OF THE GEOLOGICAL RECORD.

On the absence of intermediate varieties at the present day. On the nature of extinct intermediate varieties; on their number. On the vast lapse of time, as inferred from the rate of deposition and of denudation. On the poorness of our palæontological collections. On the intermittence of geological formations. On the absence of intermediate varieties in any one formation. On the sudden appearance of groups of species. On their sudden appearance in the lowest known fossiliferous strata.