“…Degraded or amorphous pollen are, in the absence of experimental data, often assumed to be a product of sustained biochemical or physical deterioration (Cushing, 1964;Lowe, 1982;Tipping et al, 1994;Tipping, 1995). Samples with more crumpled determinate grains have higher proportions of degraded determinate grains, but there is no such relation between severe corrosion and degradation, suggesting that degradation has an origin in mechanical damage rather than biochemical decay.…”