Researchers at Tanis, North Dakota, U.S.A., cited faulting associated with soft sediment deformation of the K/Pg boundary clay at Madrid East in the Raton Basin, U.S.A., as additional evidence of “more-instantaneous effects” that preceded the longer-term, climatic effects of the Chicxulub impact. However, Madrid East is among numerous localities where the initial phase of the K/Pg boundary fern spike initiated within rather than above the K/Pg boundary clay crosscut by this fault. Accordingly, this phase of the K/Pg boundary fern spike must have preceded the cessation of seismic aftershocks of the Chicxulub impact—a conclusion also reached by researchers at the deep marine depositional setting of Gorgonilla Island in Colombia, South America. The observation that the Chicxulub impact winter was shorter in duration than post-impact seismicity need not signify a major dilemma for contemporary climate models of the Chicxulub impact, a dilemma originally exacerbated by the common perception that this phase of the fern spike was dominated by tropical tree ferns. Because tree ferns have exceptionally long generation times (ca. 100 y according to contemporary estimates), they could not have had ample time to reach sporing stage if they were killed back to rhizomes or other belowground reserves by a complete shutdown of photosynthesis and subsequent impact winter. Alternatively, the dennstaedtiaceous affinity of spores at Madrid East suggests that these ferns had a generation time of only 2–4 y, which better fits contemporary estimates on how long it took for the effects of Chicxulub to wind down.