Echinoid (sea urchin) spines from Cretaceous strata have widely varying morphology. They are common, and most are small enough to be recovered from well cuttings. Many forms have restricted ranges; consequently, echinoid spines have substantial biostratigraphic utility.

There have been established 115 form taxa of echinoid spines and 14 form taxa of ophiuroid-asteroid spines for the Cretaceous of Texas. The specimens used for establishing the form taxa were processed from 533 outcrop samples (78 localities) from 30 Cretaceous formations, each with a well-defined age based on faunal zones of ammonites and Foraminifera. A dichotomous key in 9 parts and a catalog of scanning electron micrographs (87 plates) have been set up to assist identification of the form taxa.

Range charts for the echinoid and ophiuroid-asteroid form taxa have utility throughout the Cretaceous of much of the Gulf Coastal area. The most precise zonation has been possible for the Albian.

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