By the Cretaceous, the true cycads were apparently quite large. One fossil from Japan, a large stem over four feet in diameter named Sanchucycas gigantea, shows structural characteristics similar to both Cycas and Encephalartos.

Another fossil from Japan is a unique form of cycad unknown today. It's compound leaves had regular rows of pinnae that grew from a series of short shoots extending radially from a slender stem. Nilssoniocladus nipponense had leaves similar to the Nilssonia pattern. No reproductive material was associated with the fossil.

The Williamsonia were still present in Mexico, England and India during the Cretaceous period. This slender cycadophyte apparently depended heavily on large herbivores consuming the ripening cones and distributing the undigested seeds in its dung. This would be an obvious disadvantage should the large herbivore disappear suddenly. The cycadeoids also remained numerous, and many fossils have been discovered in the Black Hills of South Dakota, and in Wyoming. Their low- growing, stocky trunks with a prominent armor of leaf bases were often mistakenly taken for cycads. The female reproductive structures resembled flowers, but were really loose cones. Beetles apparently served as both pollinators and seed predators.

Williamsonia sp., compound leaf pattern

Williamsonia sp., a bennettitalian cycadphyte with a compound leaf pattern (see insert above) and an arborescent trunk.
Jurassic through Cretaceous

Fossil leaves from the Lower Cretaceous of Argentina described as Mesodoscolea have been assigned to the Stangeriaceae (Archangelski & Petriella, 1971). The only surviving member of this genus, Stangeria, is endemic to the coastal region of South Africa. Mesodoscolea suggests that the Stangeriaceae were a much more important family 200 million years ago, with an extensive range in Gondwana. 

With so many gaps in the fossil record it is possible that major families of the Cycadales that were once quite common remain completely unknown. The curious genus Pterosoma known only from Lower Eocene fossils near Victoria, Australia, is another example. It possessed forked veins in it's leaves, like the Stangericeae, and must have been widespread in southern Australia during the Cretaceous.

The Upper or Late Cretaceous was a time of increasing environmental stress. Gondwana and Laurasia were now in the process of breaking apart. India had become a wild "runaway" (geologically speaking) shooting across the Indian Ocean toward Asia, and a vast outpouring of magma was forming the Deccan Traps (steps). Sea levels were dropping, the deep ocean was turning cold, and the world climate was now more seasonal as mountain ranges thrust up in the Americas, Europe, and Asia. The three cycad-like families, Williamsonia, Cycadeoidea, and Cycadales, were in a contest for survival and the future would go to the most adaptable. But what no one figured on was a wild-card player arriving out of the asteroid belt.