But I do not pretend that I should ever have suspected how poor was the record in the best preserved geological sections, had not the absence of innumerable transitional links between the species which lived at the commencement and close of each formation, pressed so hardly on my theory.

The abrupt manner in which whole groups of species suddenly appear in certain formations, has been urged by several palaeontologists--for instance, by Agassiz, Pictet, and Sedgwick, as a fatal objection to the belief in the transmutation of species.

If numerous species, belonging to the same genera or families, have really started into life at once, the fact would be fatal to the theory of evolution through natural selection.