Paleontologyandcorrelation ofa LowerGretaceous (Albian) outlierin RooseveltGounty, New Mexico byBarry S. Kues,Department of Geology, University of New Mexico, Albuquerque, NM87131 Introduction to the east in Texas.Brief mention of the centerof the NW1/rsec. 30, T3S,R36E (Figs. The Tucumcari Shale is a fossiliferous for- conelation suggestedhere was made by Kues 2, 3). This localityis 3 mi north of the village mation of Late Albian age that is extensively (1986).Illustrated specimenshave been as- of Rogersand 14 mi south-southeastof Por- exposed in Quay and eastern Guadalupe signed University of New Mexico (UNM) De- tales.Lower Cretaceoussediments in this area Counties.The Tucumcaribiota is reasonably partment of Geology catalog numbers. are mostly covered by a veneer of Quater- well known (Scott,1970a, 7974; Kues et al., narv alluvium and grivels. 1985),although it has not been studied sys- Location and previous studies The first mention-of Cretaceousrocks in (1928, tematically.The formation has generallybeen The thin Lower Cretaceous section dis- this area was by Darton p.39), who considered correlative with the Duck Creek cussedin this paper is best exposedalong stated"W. B. Lang recently found outcrops Formation in Texas (Scott, t974; Scott and the eastside of an unnamed arrovo, near the containingComanche fossils 13 mi southeast Taylor, 1.977),or the Duck Creek plus part of of Portales. ." Theis (1932)reported a 15- the underlying Kiamichi Shale (Brand, 1953; ----l ft-thick Comanchean interval in section 30, Brand and Mattox, 1972).These two forma- and Robbins(1941, p. 7) listed nine "typical tions representthe lower part of the Washita l Kiamichi" mollusc taxa from the area. Lang Group in Texas.The Tucumcari outcrop belt Q9a7,p. 1476)rcfetred to "limestones of the is 350mi west of the well developed Washita Kiamichi Formation [overlying] a thin basal sequencein easternTexas (Fig. 1), but several sandy conglomerate, which in turn rests on and he Io- limited Kiamichi and Duck Creek exposures, rQg,11yCounty Triassicrocks," in RogersDraw, I probableWashita shorelineabout mainly around playa lake depressions,were Roosevell CountY cated the reported by Brand (1953)from west-central 20 mi west of the Rogerslocality. Galloway . Por exposuresand sug- Texasnear the New Mexico border. Two sim- Floyd (1956)summarized these ilar Washita-ageoutcrops have also been re- eestedthat the lower part of the sectionwas ported in New Mexico far south of the Equivalentto the lower TucumcariShale and Tucumcari area: one near Portales in Roose- to the Kiamichi, whereas the upper Part was velt County, and the other northwest of Ta- correlativewith the upper Tucumcari and the tum in Lea County. Neither locality has been Duck CreekFormation of westernTexas. He studied in detail from a biostratigraphic or Rogers also showed that the Lower Cretaceousstrata paleontological perspective, although such exposed near Rogers were Present in the information would be useful in furthering xm subsurfacethrough an area of 100 mi' that our knowledge of the paleogeography, his- o 5 ro 152025 i extendedfrom RooseveltCounty eastward torv. and faunal distribution of the Albian l-J-!--l-l+ 8l into Bailey County, Texas.Young (L965,p. o5lo15 5iI southern Western Interior seaway.In this pa- hl >l 5 49)referred these strata to the TucumcariShale per the stratigraphyof the RooseveltCouirty el* and reported the ammonoids Adkinsitesbra- outlier is described,and its paleontologyis I zi aoensis-(Bdse)and A. imlayiYoungfrom three summarizedto provide the basis for corre- I localitiesin section30. These exposures were lation with the Tucumcari Shale to the north FIGURE2-Location of the Lower Cretaceousout- consideredto be probably correlative with and with the Kiamichi-Duck Creek sequence lier (X) in RooseveltCounty. the Tucumcari Shale by Dane and Bachman (1965)and were mappedas "Cretaceous,un- divided" on the Geologicatlas of Texas,Cloais sheet(Barnes, 1978). StratigraPhy At the Rogerslocality (Fig. 3) about 15 ft of Lower Cretaceousstrata overlie 8 ft of un- FIGURE l-Distribution of fossiliferous marine Washita-age FIGURE 3-Eroded Kiamichi exposure along unnamed arroyo north of Rogers. K outcrops in the southern Western Interior (modified from indicates locality from which the fossils discussed in this PaPer were collected. View Scott, 1975),The circled locality is discussedin this paper. is to the north-northeast. November 7986 Nm Mexico Geology fossiliferous,brick-red to green-mottled transgressionof the Washitasea into Roose- consistedof fine, sharply rounded, closely Triassicmudstones, which are similar litho- velt County from Texas. spaced,concentric lirae, about 8 to 10 per 10 logicallyto intervalsin the Chinle Formation mm near the ventral margin of the shell. Sev- to the northwest and the Dockum Group in Paleontology eral steinkernsare encrustedby small oyster Texas.The Cretaceous sequenceconsists of A moderatelydiverse, predominantly mol- shells. a basalconglomerate, alternatingthin ledge- luscanfauna occurs at the Rogerslocality (Ta- Ceratostreontexanum (Fig. 55, T), the most forming limestonebeds and covered slopes ble 1). Some of the most conspicuous or abundant fossil in the lower part of the sec- of light brown to gray shale, and an upper, unusualelements of this fauna are discussed tion, occursprimarily as complete,disartic- massive,well-indurated sandstone.The basal briefly here, with the Texigryphaeaspecimens ulated valves. Specimensranging from conglomerate(Fig. a) is about 3 ft thick and consideredseparately below. The steinkerns juveniles to mature valves reaching a length is composedof gray to brown limestonewith of Cyprimeria (Fig. 5V) are nearly circular of 90 mm were collected.Variation in valve a large amount of quartz sand grains and (height : 90% of length) and range from shape,from narrow to nearly circular, is pro- subroundedto angularpebbles of quartz and about 65 to 90 mm in length. Most Lower nounced.A single,columnar, slightly curved quartzite up to 1.5 inches in diameter. Dis- Cretaceousspecies of Cyprimeriafrom Texas shell fragment about 65 mm long and having articulated valves of Ceratostreontexanum and Kansaswere establishedon the basisof an oval cross section documents the pres- (Roemer)are common, as are large stein- steinkerns and are differentiated by slight ence of rudist bivalves (Fig. 5X, Y) af this kerns of Cyprimeriasp, and Cucullaea? cf. C.? differencesin sizeand proportions.The Rog- locality. The fragment is calcareousand com- herculeaTwenhofel and Tester. One C. tex- ers specimensare considerablylarger than posed of numerous long, vertical pallial ca- anumspecimen (Fig. 5T) was cemented near C. texana(Roemer), the most commonly re- nals that are oval to polygonal in crosssection. its beak to an isolatedpebble. This conglom- ported species,and they are within thq size Thin tabulaecross the canalsat intervals along erate reflects a nearshore marine environ- range of C. crassaMeek, C. kiowanaCragin, their length. The thick, vesicularshell struc- ment that periodically received influxes of andC. washitaensisAdkins. The largestTexas ture suggeststentative assignment to the Ca- coarseclastic grains from adjacent land areas Washitaspecies, C. giganteaCragin, reaches prinidae. One specimen of a solitary coral to the west. The generallyunfragmented C. a length of 118 mm (Adkins, 1928)and is was recoveredfrom the basalconglomerate. texanumvalves and the articulated state of apparently inequivalve, whereas the speci- Gastropodsare common as steinkernsin the the bivalve steinkerns in the conglomerate mens at hand indicate symmetrical valves. lower ledge-formingsandy limestone;the few bed indicate relatively quiet normil marine The vaguecriteria used in separatingLower specimensretaining part of the shellhave an conditions, with the bivalves occupying a CretaceousCyprimeria species and the poor ornamental pattern suggestive of Turritella substratethat included numerous large peb- preservationof the Rogers specimenspre- beloidereiCragin. bles. clude definite assignment of these speci- Severalfragmentary, but identifiable,am- The middle part of the Cretaceoussection mens. monoids (Fig. 5P-R) were collected from the is 8-10 ft thick and consistsof coveredshale Largesteinkerns assigned to Cucullaea?cf. Texigryphaeahorizon. TheseKiamichi species slopeswith two thin limestonebeds in the C.? herculea(Fig. 5U) reach a length of 112 were described and illustrated by Young lower 4 ft. The lower of two conspicuous mm, havea high, anteriorbeak, and aresim- (7966. ledgesin this interval is a light brown, in- ilar in shape to C. herculeafrom the Kiowa Texigryphaea distinctly bedded limestone filled with fine Formation of Kansas. Some smaller sneci- Approximately quartz grains. Locally this unit has more the mens (lengthabout 80 mm) are posteriorly 150 specimensof Texigry- appearanceof fine-grainedquartz sandstone elongateand have a relatively low phaea,mainly isolated left valves, were col- longitu- [? with a calcareousmatrix. Steinkernsof hieh- dinal profile. Molds of taxodontdentition are spired ga-stropods(probably Turritella),ey- present along the hingelines of a few spec- TABLE 1-Lower Cretaceousfossils identified from primerh, Protocardia,and Cucullaeaare com- imens. Fragmentsof shell adhering to sev- the Kiamichi exposures near Rogers, Roosevelt mon, together with sparseshark teeth, eral steinkernsindicate that ornamentation County, New Mexico. Seetext foidetails on taxa ammonoid impressions,and oyster shell grouped here as Texigryphaeaspp.