If the number of the species included within a genus, or the number of the genera within a family, be represented by a vertical line of varying thickness, ascending through the successive geological formations, in which the species are found, the line will sometimes falsely appear to begin at its lower end, not in a sharp point, but abruptly;
Genero bereko espezie kopurua, edo familia bereko genero kopurua, espezieak aurkitzen diren jarraikako formazio geologikoetan gora doan lodiera aldagarriko lerro bertikal batez irudikatzen badira, lerroak beheko muturrean zorrotz barik bat-batean hasten dela emanen du batzuetan, nahiz eta egia ez izan;