tjw quoted At the Mountains of Madness by H.P. Lovecraft
Introduction by China MievilleLong acknowledged as a master of nightmarish visions, H. P. Lovecraft established …
Though the limestone formation was, on the evidence of such typical imbedded fossils as ventriculites, positively and unmistakably Comanchian and not a particle earlier, the free fragments in the hollow space included a surprising proportion from organisms hitherto considered as peculiar to far older periods…
— At the Mountains of Madness by H.P. Lovecraft, H. P. Lovecraft
Apparently “Comanchian” refers to early Cretaceous but isn’t used anymore. A shame that this terminology is defunct when the main thing named after Comanche people today is military equipment. The Comanchean/Comanchian would have been named indirectly via the mountains (a la my state’s Ichthiosaur species being named after the Shoshone via the mountains named after them - Shoshone also being closely related to Comanche)