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ecords have helped to pinpoint these locationsand allowed the reconciliation of the Böse (1917)Palo Pinto limestone localities to those of Scottand Armstrong (1932). Examination of exposuresof these strata, and their associated fusulinidand conodont faunas has demonstrated thatthefollowing correlations to the Canyon Groupin the type area in the Brazos River Valley inPalo Pinto County can be made (in descendingorder): (i) a conodont-rich black mudstone (indicatingmaximum transgression and a deep basinenvironment) at the base of the Wolf MountainShale and just above the Wiles Limestone correlatesto a similar interval just abovethe WillowPoint Limestone, well exposed in the areaaround the southwest shore of Lake Bridgeport;(ii) the Willow Point Limestone (= BridgeportLimestone of Böse) correlates to the WilesLimestone (top of the Posideon Formation); (iii)strata in the Martin Lake area just south ofBridgeport correlate to equivalent age conodontrichblack mudstones present in the middle partof the Posideon Formation; (iv) the Martin LakeLimestone is a fusulinid/algal grainstone containinga distinctive nankinellid fusulinacean atall outcrops and indicates very shallow marinedeposition. It correlates with the top part(=Wynn Limestone) of the Palo Pinto Formation;(v) the Hudson Bridge Limestone correlates withthe lower part of the Palo Pinto Formation. Ablack shale interval a few centimeters thickfound in a core taken in an abandoned quarry inthe Palo Pinto Formation in southwestern WiseCounty is correlated to a crinoid - conodont-rich10-25cm unit that marks the base of the PaloPinto Formation on top of the Keechi CreekShale in much of Palo Pinto County.The newcorrelation of the Willow Point Limestone, theuppermost member that Scott and Armstrong(1932) reported asbeing in the Palo Pinto Formation,and its placement into the overlyingPosideon Formation, leaves six limestone membersin the Palo Pinto Formation identifi ed inWise County. Its top and bottom members, theMartin Lake Limestone and theHudson Bridge Limestone, respectively, now arefirmly correlated to the top and bottom, respectively,of the Palo PintoFormation in the typearea.2008040531美 国 得 克 萨 斯 Wise 县 Canyon 群 下 部 ( 上 宾夕 法 尼 亚 亚 系 密 苏 里 阶 ) 的 多 因 素 地 层 和 新的 对 比 标 准 = Multi-factored stratigraphy andnew correlation standards in the lower part of theCanyon Group (Missourian, Upper PennsylvanianWise County, Texas: A can of worms untangled.( 英 文 ). Kimball R A; Nestell M K.Stratigraphy, 2007, 4(4): 329-352,Several Late Pennsylvanian (Early Missourian)age limestone beds exposed in isolated outcropsin the Trinity River Valley in southwestern WiseCounty and named by Böse (1917), and Scottand Armstrong (1932) are assigned tothe Palo Pinto Formation (lower part of the CanyonGroup). Clearly designated type localities ortype sections were not given for some limestonebeds named in these two previous studies. Theselimestone units in southwest Wise County occurin coherent stratigraphic sequences in three keyareas: along Dry Creek, around Martin Lake, andalong Boons Creek. Original type localities havebeen located and suitable reference sections havebeen established for these limestone beds. TheCanyon Group was established for outcrops ofstrata in the Brazos River Valley. Correlation ofstrata between the type area and strata in theTrinity River Valley is based on stratigraphicposition, textural characteristics of the limestone,and similarities in fl ora and fauna, including thepresence of distinctive algae and fusulinaceanspecies of Triticites and Nankinella. Equivalenceof several of the units named by Scott and Armstrong(1932) is established: the Boone CreekLimestone and Hudson Bridge Limestone; theSanders Bridge Limestone and unnamed (Yl4)limestone; and the Martin Lake Limestone andBalsora Limestone. The names fi rst used in theliterature and retained here are the Boone CreekLimestone, Sanders Bridge Limestone, and theMartin Lake Limestone. Two additional limestoneunits present between the Martin LakeLimestone and the Willow Point Limestone areformally designated here as the Bridgeport RoadLimestone and the Kirkman Limestone. The findings of this investigation follow the CanyonGroup nomenclature established by Laury(1962). The two new limestone units, along withthe Bridgeport Coal and the Willow Point Limestone,are placed in the Posideon Formation,with the Willow Point Limestone forming thetop member. In the Posideon Formation, theBridgeport Road Limestone may correlate to oneof the lower limestone units within the Pp1 shaleof Laury (1962) in the type area. The timesynchronousoverlying conodont rich core shalehas been correlated previously to the Pp1 shalein the type area. The Kirkman Limestone is correlatedto the Pp2 limestone, and the WillowPoint Limestone to the Wiles Limestone, bothcorrelations based on the presence of overlyingtime-synchronous core shale in both river valleys.The Sanders Bridge Limestone is correlatedto the middle of the Palo Pinto Formation in thetype area in the Brazos River Valley.中 生 界2008040532161