Tiers of Time and Trials of Extrapolationism 1331
the famous conclusion from Hatcher, Marsh and Lull's 1907 monograph on the
anatomy, taxonomy, evolution and extinction of ceratopsian dinosaurs. In ending
their text with a section on "probable causes of extinction," these three great
paleontologists only allowed themselves to consider the two standard hypotheses of
the conventional uniformitarian school of pure extrapolation, complete with its
Darwinian assumption that vectors of general progress must pervade such systems (in
this instance by the replacement of dinosaurs with mammals, for reasons of warm-
blooded superiority in anatomical design and mentality). In either case, they argue,
the extinction must spread through an extended time in several episodes, step by step.
The two reasons themselves—biotic competition from a superior group, and adaptive
failure in the face of changes in the physical environment imposed by ordinary
terrestrial forces (acting at greater than their usual intensity, but still in their
characteristic mode)—cause inferior groups to peter out as life gets better and better
through each geological day:
Several theories have been advanced as to the probable causes of extinction of
the Ceratopsia ... It seems that animals of another race, or hordes of creatures
which emigrated from another region, would be more likely to exterminate
their predecessors. The mammals fulfill the requirements of a new foe, and the
development of the frill in the Ceratopsia has been considered as meeting the
necessity for a better protection of the neck blood vessels from the weasel-like
attack of small but bloodthirsty quadrupeds. Another notion... was that the
Cretaceous mammals sought out the eggs of dinosaurs and destroyed them—
Cope even going so far as to suggest the Multituberculata, with their long,
sharp anterior teeth, as the probable offenders...
By far the most reasonable cause... seems to be changing climatic
conditions and a contracting and draining of the swamp and delta regions
caused by the orographic upheavals which occurred toward the close of the
Cretaceous. The Ceratopsidae and their nearest allies, the Trachodontidae,
both highly specialized plant feeders, were unable to adapt themselves to a
profoundly changed environment because of this very specialization, and, as a
consequence, perished.
That the Ceratopsia made a gallant struggle for survival seems evident, for
they lived through the first series of upheavals at the close of the Laramie and
also the second series at the close of the Arapahoe, which were accompanied
by great volcanic outbursts in the Colorado region; but the changes
accompanying the final upheaval which formed most of the great western
mountain chains and closed the Mesozoic era gave the death blow to this
remarkable race (Hatcher, Marsh and Lull, 1907, p. 195).But new perspectives from two higher tiers have reversed this conventionality,
particularly for a vigorous group like the ceratopsians. At the second tier, these
particular dinosaurs, among all other subclades, remained in maximal flourish of
expansion and speciation right to the close of Cretaceous