BUREAU OF ECONOMIC GEOLOGY The University of Texas Austin 12, Texas JOHN T. LONSDALE, Director Report of Investigations —No. 14 Recognition of Hipparions and Other Horses in the Middle Miocene Mammalian Faunas of the Texas Gulf Region By James Harrison Quinn and New Paleocene and Lower Eocene Vertebrate Localities, Big Bend National Park, Texas By John A. Wilson, Ross A.Maxwell,John T. Lonsdale, and James H. Quinn May 1952 BUREAU OF ECONOMIC GEOLOGY The University of Texas Austin 12, Texas JOHN T. LONSDALE, Director Report of Investigations —No. 14 Recognition of Hipparions and Other Horses in the Middle Miocene Mammalian Faunas of the Texas Gulf Region By James Harrison Quinn and New Paleocene and Lower Eocene Vertebrate Localities, Big Bend National Park, Texas By John A.Wilson, Ross A.Maxwell, John T. Lonsdale, and James H. Quinn May 1952 Contents Pagb Recognition of Hipparions and Other Horses in the Middle Miocene Mammalian Faunas of the Texas Gulf Region, by James Harrison Quinn.... New Paleocene and Lower Eocene Vertebrate Localities, Big Bend National Park, Texas, by John A. Wilson, Ross A. Maxwell, John T. Lonsdale, and James H. Quinn 9 Recognition of Hipparions and Other Horses in the Middle Miocene Mammalian Faunas of the Texas Gulf Region James Harrison Quinn New information concerning the ances- poses the fauna may be called the Oakville try of the later Tertiary horses, Calippus, fauna. Protohippus (in the original sense), Hip- The age of the Oakville fauna is appar- parion, Neohipparion, and Nannippus, has ently Arikareean, just earlier than the been obtained from a restudy of the vari- Thomas Farm local fauna, in Florida, of ous mammalian faunas of the Coastal the Tampa(?) formation. The presence of Plain in Texas, based in the main on the Tomarctus canavus, Floridatragulus, Oxy- extensive collections of the Bureau of Eco- dactylus, Parahippus leonensis (velli- nomic Geology, The University of Texas. cans), and other forms specifically com- The age, stratigraphic correlation, and mon to the two faunas attests to the close- composition of these faunas have been re- ness of time relationship between them. evaluated, and the results provide new evi- However, the Thomas Farm fauna contains dence that has important bearing on Mio- a somewhat more advanced form, Mery- cene and Pliocene intercontinental corre- chippus gunteri, not found in the Oakville. lations of mammalian faunas. It is the It would thus appear that the Florida opinion of the writer that these five genera horses are a little more advanced, and the of horses, among which the three genera Thomas Farm fauna is correspondingly Hipparion, Neohipparion, and Nannippus slightly younger than the Oakville fauna are commonly called the Hipparion group, of Texas. originated from the lower Miocene genus A series of fossiliferous strata overlying Parahippus and hence made their first ap- the Oakville and known as the Fleming pearance in the middle Miocene. (or Lagarto) formation contains a diverse The late Tertiary mammalian faunas of fauna, which may be designated the Flem- the Texas Gulf Coastal Plain occur in ing fauna. It embraces the Cold Springs, three discrete horizons which, according to Noble Farm, and Burkeville local faunas. previous workers (Wood et al., 1941), are In the vicinity of Burkeville commingled distributed as follows: middle Miocene, vertebrate and terrestrial and aquatic in- represented by the Cedar Creek and Garvin vertebrate fossils occur. The Burkeville Gulley local faunas; upper Miocene to horizon has been correlated by its inverte- lower Pliocene, represented by the Noble brates with the middle Miocene, Florida Farm local fauna and Cold Springs and Hawthorne (Stenzel, Turner, and Hesse, Burkeville faunas; lower to middle Plio- 1944, pp. 997-1000) . cene, represented by fossils of the Goliad Remains of Floridatragulus, Tomarctus formation. canavus, and horses very closely related The Cedar Creek and Garvin Gulley to P. leonensis, but with the crotchet local faunas are segments of a fauna con- attached, are found in the base of the tained in the lower Oakville sandstone. Fleming. Hence a very close time rela- The sandstone is known to extend from tionship is indicated between the basal Duval County, near the Mexican border, Fleming, the Thomas Farm local fauna in to a few miles northeast of Navasota, Florida, and the Oakville fauna, with the Grimes County, but may actually be first-listed the youngest and the last-listed traceable farther east, although it may no the oldest. longer be a prominent scarp-forming sand- Although mastodonts, Alticamelus, and stone in eastern Texas. The Oakville sand- Teleoceras appear in the middle of the stone overlies the Catahoula formation, of Fleming and not earlier, the Fleming fauna supposed Oligocene age. The fauna con- seems to represent a single unit, since some tained in the Oakville sandstone has been species persist without noticeable change traced from the locality of Cedar Creek to from the base to the top of the formation, that of Garvin Gulley. For present pur- as known at present. — 6 Report of Investigations No. 14 Among the horses all the Pliocene thetoceras, Merycodus, and Gnathybelodon. groups except Pliohippus are present in Of these Gnathybelodon is the only animal the Fleming fauna. Of these Calippus is which might indicate a later, Pliocene, age. represented by a large and a small species However, presence of horses in the Goliad, and is more easily recognized than any of not known in the Texas High Plains depos- the other genera. A Protohippus much like its, indicates a slightly earlier age for the P. perditus but with considerably shorter- Goliad. Because the two areas are so crowned teeth is sparsely represented. Of closely situated geographically, it would the Hipparion group, Nannippus and Neo- seem that the faunas should be almost hipparion can be distinguished, but separa- identical if they were of the same age. tion is difficult. A number of isolated teeth Certainly the Goliad fauna resembles the have round-oval protocones and very com- Clarendon much more closely than the plexly folded enamel. These appear to Fleming. represent ancestral Hipparions. The Gulf Coast faunas of the Miocene All these horses are obviously more appear to be distinct from those of the primitive than their Pliocene descendants, Great Basin and the West Coast as well but they are generically separable and can- as those of the High Plains. Separate not be assigned to the genus Merychippus. faunal provinces, with restricted commu- Furthermore, these horses cannot be con- nication but not complete isolation, are sidered as belonging in the Pliocene or indicated. The nature of the barriers is upper Miocene. The fauna contains forms not known. These restrictions to inter- that may be considered relict, such as mingling seem to have been relaxed at Desmathyus and Diceratkerium. However, the end of Miocene time, permitting the the species of genera more properly as- Gulf Coast faunas to invade the North. sociated with a later stage, such as Teleo- In conclusion, the Texas Gulf Coast ceras and Aelurodon, are much more formations contain faunas of lower, mid- primitive than are the late Miocene or dle, and upper Miocene age, distinct from Pliocene species of these genera. Likewise those of the North and West. These Texas the marine correlation indicates middle faunas include the hitherto not recognized Miocene. All available evidence leads to ancestors of various genera of Pliocene the conclusion that the Fleming is middle mammals. Of these, certain of the horses Miocene in age, its base lower middle are not referable to the genus Merychippus, Miocene, and its top not later than upper and Merychippus, in the generally ac- middle Miocene. cepted sense, can no longer be considered The Goliad formation overlies the Flem- as ancestral to the Pliocene genera. The ing and is best exposed in the Beeville- horses from the Fleming are primitive Goliad area. The fauna, which may be members of Calippus, Protohippus, Nan- called the Goliad fauna, seems to be nippus, Neohipparion, and Hipparion. closely related to the Clarendon fauna Finally, the Gulf Coast beds can be re- insofar as the teleocerine rhinoceroses and lated to the continental Florida lower certain of the horses are concerned. Plio- Miocene, the marine middle Miocene Haw- hippus is sparsely represented; Calippus thorne section, and the High Plains forma- placidus and regulus are not uncommon. tions. Neohipparion and Nannippus are quite REFERENCES numerous. are There other horses in the Stenzel, H. 8., Turner, F. E., and Hess, C. J. fauna including a large calippine and a (1944) Brackish and non-marine Miocene in hipparionid, which has round-oval proto- southeastern Texas: Bull. Amer. Assoc. Petr. cones and complexly folded enamel pat- Geol., vol. 28, pp. 977-1011, figs. 1-7. (1941) terns is probably to Hippa- Wood, H. E., et al. Nomenclature and and referable correlation of the North American continental rion. The fauna also includes Amphicyon, Tertiary: Bull. Geol. Soc. Amer., vol. 52, pp. Aelurodon, Alticamelus, Procamelus, Syn- 1-48, 1 pi. New Paleocene and Lower Eocene Vertebrate Localities, Big Bend National Park, Texas John A. Wilson, Ross A.Maxwell,John T. Lonsdale, and James H. Quinn During the course of a comprehensive This reconnaissance produced the fol- geological survey of Big Bend National lowing results: Park, Brewster County, Texas, Maxwell 1. Discovery of a distal end of a femur and Lonsdale noted strata of questionable of eohippus and a tooth fragment of Cory- age in the valley of Tornillo Creek north phodon in the basal conglomerate at the of the Chisos Mountains. This is the gen- bottom of the sandstone. eral type locality of Udden's (1907) late 2. Discovery of eohippus teeth and Cretaceous Tornillo formation, and the Coryphodon bones, turtles and crocodilian area along the creek for several miles is fragments in the clays below the con- known locally as Tornillo Flat.