Recent Discoveries of Cretaceous Marine Vertebrates on the Eastern Margins of the Western Interior Seaway
Stephen L. Cumbaa I and Tim T. Tokaryk 1
Cumbaa. s. L. and Tokaryk. T.T. ( 1999): Recent discoveries of Cretaceous marine vertebrates o~ the eastern margin_s of the . Wcstemlntcrior Seaway; i~ Summary of Investigations 1999. Volume I. Saskatchewan Geolog1cal Survey, Sask. f: nergy Mmes, Misc. Rep. 99-4. 1.
1. Introduction 1936; Wickenden, 1945; Beck, 1974). A detailed study and synthesis of these Cretaceous rocks and their A joint Royal Saskatchewan Museum- ~anadian . Foraminifera by McNeil and Caldwell (1 981 ) led to Museum of Nature field project began m I 991 with the this research. goal of examining Late Cretaceous marine deposits to learn more about the evolution of the northern part of To date our research has concentrated primarily on the Western Interior Seaway and its vertebrate faunas. deposit; of the Belle Fc_mrche Member (Cenoma_n ian) The project built on earlier collecting along t~e Carrot of the Ashville Formation and the Favel Fonnat1on River by Royal Saskatchewan Museum ~taff m _1959 (Turonian), with some exploration of the Niobrara and again in 1986, but was ~parke1 by d1scov~nes Fonnation (Coniacian-Santonian) (Figure I). . made by Mr. Dickson Hardie on hts farm, which Formation descriptions and ages follow McNeil ( 1984) borders the river near Arborfield. Fossils discovered by and McNeil and Caldwell (1 981 ). Mr. Hardie, and subsequently donated by him to the RSM include bones and teeth of fishes and bones of plesi~saurs, turtles, and birds. The diversity and 2. Previous Vertebrate Paleontological abundance of the fossil material sparked an immediate interest in the Cretaceous deposits in the Carrot River Studies area. In several fi eld seasons since then, our team has The chalk badlands of Kansas and adjacent states in the expanded its geographical scope to include most of the US Midwest have been fertile collecting grounds for Pasquia Hills area. This paper describes some of our marine vertebrate remains for well over a century, but recent discoveries and discusses future research. until comparatively recently, the Western Interior Seaway deposits in Canada, and especially those on its a) Geological Setting eastern margin, received little attention. Whiteaves ( 1889) described two sharks and two bony fishes from During most of the last 35 million years of the Manitoba Cretaceous deposits. Also mosasaur Cretaceous, an epicontinental seaway divided North (Anonymous, 1934) and plesiosaur fossils (Russell America, linking the arctic Boreal Sea to the wann 1935) have been described from Manitoba. Tethyan Sea of southern latitudes. At its maximum, the seaway extended from the newly-fonned Rocky Bardack ( 1968) was the first to systematically collect Mountains eastward to what is today western Ontario. and describe vertebrate fossi ls, primarily fish, from An overview of the Western Interior Seaway within the Manitoba localities along the Manitoba Escarpment. context of Cretaceous North America is provided by Russell ( 1988) compiled published reports of fossil Russell ( 1989). In eastern Saskatchewan, alternating vertebrates from the entire seaway. Case et al. ( 1990) transgressive pulses and regressive cycles are recorded describe selachians from a locality along the Carrot in several hundred metres of sediment that were River in Saskatchewan, and Nicholls et al. ( 1990) deposited from the Late Albian through most of the identify marine turtles from several localities in Maestrichtian. Manitoba and from a locality along the Carrot River. In the most recently published report on fossil vertebrates Cretaceous strata crop out where cut by rivers along from the region, Tokaryk et al. (1997) describe new the Manitoba Escarpment in southwestern Manitoba taxa of marine birds from a Cenomanian deposit along and east-central Saskatchewan. The Escarpment, which the Carrot River. is 675 km in length, forms the eastern erosional edge of the Western Interior Basin. Our study area, the Pasquia Russell ( 1993) discusses the evolution of the vertebrate Hills near the Manitoba border between the faunas of the seaway and characterizes them in a Saskatchewan and Red Deer rivers in Saskatchewan, temporal series of assemblages defined by flexible represents the most northwestern of the fi ve uplands of intervals of taxonomic change (fauna! turnovers), not the Manitoba Escarpment. The Escarpment has been by lithostratigraphic referent. He refers to these the subject of geological study for many years assemblages as North American Marine Vertebrate (Mcinnes, 1908; Ells, 1923; McLearn and Wickenden,
'Canadian Museum of Nature. Palcobiology. P.O. Box 3443, Station D, Ottawa, ON Kl P 6P4. 1 Royal Saskatchewan Museum. F.asten Saskatchewan Geological Survey 57 SOUTHERN the upper part of the Belle FOOTHILLS PLAINS MANITOBA Fourche, with a middle to late afterMcNe~ afterBlochetal, 1993 afterBlochetal, 1993 and Caldwell 1981 Cenomanian age (Figure 1) . unna= Vertebrate fossils are found Bearpaw Bearpaw Q) Odanah disarticulated in a thin, hard, ...... discontinuous bioclastic layer .~E Carnpanlan 0..LL Millwood (Figure 3) capped by a 3 to 5 cm Pembina thick bentonite. The layer is very Belly River Milk River hard and resistant to acid, making Vertebrate Fossils 3. Current Research in the Pasquia Hills Reptiles: A number of elements from marine reptiles Field work by our team has focused on several have been identifi ed, including almost I 00 bones of localities clustered in the three areas highlighted in plesiosaurs, representing primarily pliosaurids but also Figure 2, with the goal of finding mid-Late Cretaceous elasmosaurids. Two vertebrae from a small vertebrates, and placing them within a stratigraphic and ornithischian dinosaur have also been identified. Two a paleoenvironmental context. In the text, Royal bones of marine turtles were described from this Saskatchewan Museum locality numbers have the locality by Nicholls et al. ( 1990), including one "SMNH" prefix. protostegid. The turtle bones were reported to be Coniacian in age as the deposit was thought at the time a) Carrot River Area of publication to represent the Niobrara Formation. SMNH Locality 63E03-0001 Birds: Tokaryk et al. ( 1997) describe five new taxa of birds from this locality, the oldest diverse avifauna known from North America. Two of the birds, Geology and Invertebrate Biostratigraphy Pasquiaomis hardei and P. tankei, are hesperomithiforms; toothed, flightless diving birds that The stratigraphically oldest locality is a I to 2 m thick were roughly the size of a loon. Two species of the exposure along the Carrot River. It is made up of soft, genus lchthyornis are described, the oldest so far carbonaceous dark shale characteristic of the Belle reported. lchthyornithiforms were small , toothed. tem Fourche Member of the Ashville Formation (McNeil li ke fl yers. The fifth bird taxon is a possible and Caldwell, 1981 ). Analysis oflithology, pollen, enantiomithine. In total, some 200 bird bones have dinoflagellates, and Foraminifera places this local ity in been recovered from the locality. 58 Summary of In vestigations 1999. J'ol11me I SASKATCHEWAN A M L A B N E I R T T 0 A B Figure 3 - Sample from the bioclastic layer at SMNH locality 63£03-0001. Overall dimensions are 12 cm by A JO cm. At top left is an unidentified marine reptile bone; at Carrot River center left an ichthyodectid vertebra; below it to the right is the black, finely-striated tooth ofa bony fish, Protosphyraena sp.; the 2 cm wide ridged tooth at right center is from a pavement-toothed shark, Ptychodus (j)~- -® occidentalis. Numerous other shark teeth are evident, i11cluding a grouping at top right ofthre e sharply-angled Hudson Bay• teeth ofSqualicorax sp. surrounding the root and part of @ the crown ofa lamniform shark, possibly ofth e genus Protolamna. SMNH Locality 63[04-0001 O Regina Geology and Invertebrate Biostratigraphy This locality is an 8 m thick exposure dominated by well-layered, white-speckled, calcareous shale. At least si x interbeds ofbentonite are preserved. The Laurier Limestone, a regional marker described by McNeil and Caldwell ( 1981 ), is present in the upper few metres of the outcrop. This unit is composed of two 15 to 20 cm thick limestone beds separated by a bentonite bed 14 cm in thickness. Based on lithology and fossi l 500km content, strata at this locality are placed within the Figure 2 - Fost,'il vertebrate localities mentioned in the text Keld Member of the Favel Fonnation (Figure I). in the vicinity ofth e Pasquin Hills. I) Carrot River localities (Ashville a11d Favelformatio11s); 2) Bainbridge Preliminary analysis of the Foraminifera (McNeil, River localities (Ashville, Favel, Morden, am/ Niobrara 1992) suggests the age of these rocks to be late formation.r); and 3) Etonwmi River localities (Niobrara Cenomanian? to early Turonian, in the and Pierre formations). Clavihedbergella simplex Subzone of the Hedbergel/a loetterlei Zone (Caldwell et al., 1978). Extensive Fisl,: Fish bones and teeth are the most abundant sampling of molluscs by Christopher Collom of the fossils recovered from this locality; teeth are more University of Calgary confirms the abundance of common than bones. Selachians include sharks of the in occramids, particularly Mytiloides labiatus. The only genus Hybodus; at least two species of Ptychodus, P. ammonite found, in a concretionary zone above the decurrens and P. occidentalis; Cretoxyrhina mantelli; primary bone-bearing strata, is Collignoniceras Cretolamna appendiculata; the genera leptostyrax and woo/gari. These invertebrates indicate that these strata another lamnifonn, possibly Protolamna; and one or are early Turonian in age. more species of the genus Squalicorax. including S. curvatus and an undescribed species of this genus known from Texas and Kansas (Welton and Farish, Vertebrate Fossils 1993). Teleosts include Protosphyraena, Enchodus, and an ichthyodectid, probably !chthyodectes Only the upper few metres of this locality have been ctenodon. extensively sampled for vertebrates. The well preserved skeleton of a 6 to 7 m long marine crocodyli form, Te/eorhinus robustus, was recovered Saskatchewan (ieolol(ica/ Survey 59 about a metre below the Laurier Limestone. This The first samples of the Bainbridge River bioclastic gavial-like specimen is the most complete and best layer were found in the river bed during fieldwork in preserved known example of its kind. A manuscript by 1994, and it was not until the following year that we Xiao-Chun Wu and Anthony Russell of the University were able to attribute it to its probable source at the of Calgary and one of us (SLC) describing the base of a 25 m thick exposure. specimen and its relationships to other known crocodyli fonns is in preparation. No other marine Many large pieces of this bioclastic material were reptiles have been found at the locality, nor any birds. collected at this locality, but none was fo und fa rther upstream. Extensive late summer and spring tloods Selachian taxa collected at the locality include the considerably alter these exposures, collapsing cliff sharks Ptychodus whipplei, Cretolamna appendiculata, faces and eroding banks, and although a concerted Cretolamna cf. C. woodwardi, Cretoxyrhina manrelli, effort was made again in 1997. the bone bed has still Odontaspis sp., Squalicorax curvatus, Squa/icorax not been identified in situ. However, in 1995 we falcatus, and an undescribed species of this genus collected large boulders of bone bed apparently (Welton and Farish, 1993). Teleosts remains are freshly-derived from the source, with soft, black abundant, particularly at roughly the same stratigraphic carbonaceous shale adhering to them. level as the Teleorhinus. Articulated ske letons of three Micropaleontological contents of the shale will be of the giant (4 to 5 m) ichthyodectid Xiphactinus audax compared with those of measured samples taken in situ and several specimens of the 30 to 40 cm herring-like on the cliff face in 1995 and 1997, and may enable us Apsopelix anglicus have been found, as well as one to confi nn our tentative placement of the bone bed at Pachyrhizodus minimus. Remains of Enchodus, or near the base of the exposure. Gillicus, /chthyodectes, and Protosphyraena have also been identified, but much work has yet to be done on The bone bed is at least as old as the Carrot River scattered, isolated remains found in several " fi sh hash" bioclastic layer, but is different in lithology and in zones. some details of its appearance (Figure 4 ). Both bone beds have large bone and teeth inclusions, generally Case et al. (1990) reported on selachian teeth found in randomly oriented, and abundant disarticulated bird, an "oyster layer" at this locality a number of years ago. plesiosaur, shark, and bony fi sh remains. The We have found similar matrix at the locality in small , Bainbridge bed is thicker (up to 0.4 m or more), has loose blocks, but to date have not been able to match many phosphatic "pebbles" and coprolites as them with strata in situ. Our search for the source inclusions, and is characterized by occasional calcite stratum will continue during future fie ld work. lined vugs up to several centimetres in each dimension, the result of diagenetic changes to rip-up clasts of Three new selachian taxa are described by Case et al. bentonite. The Bainbridge bioclastic material breaks ( I 990): two sharks, Odontaspis saskatchewanensis and down relatively easil y when immersed in mild acetic Synodontaspis lilliae, and a ray, Cretomanta acid (Figure 4). canadensis. These are associated with a mollusc-eating pavement-toothed shark, Ptychodus cf. P. rugosus, and This bed possibly correlates to the Fish Scales Marker other sharks including Cretodus sp., Cretoxyrhina Bed, a un it that is preserved over a large area in the mantelli, Squalicoraxfalcatus. and the ray Rhinobatos Western Interior. The base of the Fish Scales co incides sp. The oysters were identified by James Haggart of the with the Albian-Cenomanian boundary (Figure I); this Geological Survey of Canada (Vancouver) as Ostrea sp. cf. Ostrea congesta var. bentonensis Logan. Whereas Case et al. ( 1990) ascribe a Coniacian age to this fossil assemblage, based at least in part on the erroneous identification of the strata as Niobrara Fonnation, location of its source stratum may enable us to determine if it is Coniacian or Turonian in age. b) Bainbridge River Area SMNH Locality 63E09-0003 Geology and Invertebrate Biostratigraphy Exploration of localities ofCenomanian age in the Pasquia Hills, using McNeil and Caldwell' s ( 1981) work as a guide, led to the discovery on the Bainbridge River of a second bioclastic "bone bed" (Figure 2), Figure 4 - Bone bed showing phosphatic pebble to I 00 km to the northeast of the Carrot River bone bed immediate right of scale bar, coprolites (mo1·t ofth e semi ( in the vic inity of Outcrop Section 2 1, McNeil and ovate white f ragments), hone (primarily i,1 hlack, such as the fl.th vertebra above center of scale bar and the 2 cm Caldwell, 1981 ). Jong bird bone at the upper left), amt calcite-lined vug at upper right. 60 Summary of Investigations 1999, Volume I boundary is placed at the base of the Belle Fourc~e Member in the Manitoba Escarpment area (Leckie et al., 1992; McNeil, 1984; McNeil and Caldwell, 1981 ). T ,.., ~ At this locality, some 3 m above the base of the .,. exposure, is a 2 to 4 cm thick layer of stonn-tossed oyster shells mixed with a few disarticulated vertebrate remains, possibly the Ostrea beloiti beds. Above this layer is a 22 cm thick bentonite, possibly another T't • widespread marker in the west, the " X" bentonite. r• Biostratigraphic description of this locality is in progress by C. Collom, who is studying the well .,. >. preserved and abundant inoceramids from collections and measurements made in 1995, and by Schroder Adams et al. (preliminar1 results this volume) who worked with us in the field in 1997. Although, the data sets have not been combined, it is clear that the locality Figure 5 - Shark teeth recovered from bioc/astic layer incorporates a significant portion of the Ashville include (L to R) eight teeth of Hyb odus; four teeth of Formation, all of the Favel Formation, and at least part Ptychod11s; four odontaspid teeth, cf Carcharias; and five of the Morden Shale (sensu McNeil and Caldwell, teeth ofSqualicorax. Scale bar in centimetre.{. 1981). Enchodus have been identified from the bone bed: £. gladiolus, E. petrosus, and E. shumardi. Many well Vertebrate Fossils preserved vertebrae and teeth are yet to be identified. Most of our work on the vertebrate fauna from this locality has concentrated on the bone bed; however, in c) Etomami River the white-speckled shales of the Favel Formation we have collected the remains, some of which are SMNH Localities 63009-0001 and 63009-0002 articulated, of bony fi shes such as Pachyrhizodus, Enchodus. Apsopelix. lchthyodectes, and Xiphactinus. Geology and Invertebrate Biostratigraphy The oyster layer in the Belle Fourche Member of the Ashville Formation has produced teeth of Xiphactinus Two adjacent exposures only a few metres in height (6 and the dentary of a small ichthyodectid. and 5 m, respectively) are located on the Etomami River south of Hudson Bay [Outcrop Section numbers Disaggregation of the bone bed in the laboratory using 25 (63009-000 I) and 26 (63009-0002) in McNeil and 5 to IO percent acetic acid buffered by calcium Caldwell, 1981 ]. The contact between the Niobrara orthophosphate has yielded tens of thousands of Formation and the overlying Pierre Formation is individual bones and teeth. Numerous bird bones have readilv discernible. Numerous bentonites in the Pierre been recovered, including those of hesperomithifonns attest 'to the high degree of volcanic activity in the and ichthyomithifonns, but they have not yet been Campanian. The upper part of the Niobrara is fairly studied. Plcsiosaur bones are present in small fi ssile. with selenite crystals abounding. The lowest quantities, but have not been useful in separating taxa. parts of th e Niobrara, at or below water level, are much A fe w turtle bones have been found, but they have not less fi ssile. This unit contains two Pseudoperna as yet been studied. Recently teeth and portions of the congesta oyster layers 0.3 m apart. jaw of two different tax a of lizards were recovered. Fish bones and teeth are very abundant, and are in an Vertebrate Fossils early stage of analysis. Intact cranial clements are rare, but teeth and vertebrae are common. Selachian taxa We have done very little co ll ecting in the Pierre in clude Hybnd11s, Ptychodus. Odontaspis, Carcharias. Formation at the locality, and record only a few .liqualicorar: c11rvatus. "Squalicorax sp. " (Welton and degraded marine reptile bones from its base at the Farish, 1993 ). Chiloscyllium. and an un identified contact with the Niobrara, and a probable plesiosaur orectolobifi.)rm (Figure 5 ). tooth in the upper part of the Niobrara at McNeil and Caldwe ll's ( 198 1) Outcrop Section 25. Small numbers Bony fish es include som e unusual and potentially very of Enchodus and other teleost bones, and one interesting taxa. namely an early eel, an early Xiphactinus scale were collected in the Pierre at salmoniform, an acanthopterygian, and several large McNei l and Caldwell 's ( J 98 1) Outcrop Section 26. conical teeth referable to the genus Elopopsis (J.D. The upper part of the Niobrara is productive for small. Stevvart. pers. comm., 1997). A pycnodont similar to di sarticul ated vertebrate fossil s. especia ll y those of Micropycnodon has been identified from severa l Enchudus. Only during a 1995 visit was the water level indiv idual teeth and tooth plates. Protosphyraena, low enough to expose the lower part of the Niobrara at lchthyude,.:res. and an albul id are al so present, as are both localities. The unit produced a number of larger Apsopelix and Pachyrhizodus. Three species of fossil fish spec imens that have not yet been identified, Saskalchewan Geolo~1cal S11ri:ey 6 1 and one fairly large lamniform shark tooth from a to collect on their properties, and Dickson and Garth species as yet undescribed. for their help, interest, support and generous donations of fossils to the Royal Saskatchewan Museum. Thanks for help in the field to John Storer, Kevin Conlin, 4. Discussion Norine Leibel, Bill Caird, Larry Gagnon, Barb Caird, Jill Bell, Janice Taschuck, Terry Chadwick, Colin Abundant vertebrate specimens and other geological Longpre, Grant Schutte, Dean Hoffart, staff of the and paleoenvironmental data have been collected from Royal Saskatchewan Museum, and Bill Cumbaa. Cenomanian and Turonian strata in this little-known Thanks also to the friendly and helpful folks in the part of the Western Interior Seaway. Identification of communities of Arborfield and Carrot River, including taxa is ongoing and interpretation of the various data is Jim Kellett, who loaned us his canoe. Bill and Doris in the preliminary stages. The vertebrate fauna from Unger at the Treeline Motel in Hudson Bay have been these Pasquia Hills localities contains many " firsts", very helpful and supportive over several seasons. "oldests", and interesting combinations not found Richard "Ricco" Day has been a mainstay in the field elsewhere. These sequential faunas have at the same and in the lab. " Colorado" Chris Collom, David time both regional and cosmopolitan aspects - sharks McNeil, J.D. Stewart, Claudia Schroder-Adams, Dale and bony fishes that ranged from Texas to the Pasquia Leckie, John Bloch, and Chris Gilboy have lent us their Hills to Europe, and birds that are not currently known professional expertise in the field and the lab, and to have occurred anywhere else in the world. Chris Fielitz has helped identify fish remains. David Jarzen and Scott Ercit have contributed significant Due to the large samples, particularly from the palynological and electron microprobe analyses, bioclastic layers, taxa identification is far from respectively. We thank Clayton Kennedy for preparing complete. Outlined below are some of the subjects that the fossils, and a team of volunteers for picking will be addressed as more data become available. through the residue for fossil "gems": Dale Patten, Lisa Munro, Heather Finlayson, Heather Lemieux, Rebekah I) Paleobiogeography of the northeastern part of Rooney, Kym Stein, and Emily Croteau. This work has the seaway: These localities lie at the edge of the been supported by Canadian Museum of Nature overlap zone between Kauffman's (1984) Research Advisory Committee grants to Cumbaa, and proposed "Northern Interior Subprovince" and his from Nature Saskatchewan to Tokaryk. "Western Interior Endemic Center" biogeographic subdivisions of the seaway. As our work progresses it will be interesting to compare 6. References northern and southern faunas from Cenomanian and Turonian localities within the seaway to look Anonymous ( 1934 ): Mosasaurian skeletons from for clinal and other patterns, much as Nicholls and Manitoba at the National Museum of Ottawa, Russell ( 1990) did with Campanian faunas. Canada; Paris, League of Nations, Les Musees Scientifique, lnfonnation Mensuelle, Nos. 17-18, 2) Origin of the bioclastic bone beds: Preliminary p241-244. evidence suggests that the Cenomanian bone beds were deposited in nearshore shallow water Bardack, D. ( 1968): Fossil vertebrates from the marine depositional environments. However, more Cretaceous of Manitoba; Can. J. Earth Sci., v5, detailed sedimentological, taphonomic, and pl45-153. diagenetic studies are required to determine their origin. Beck, L.S. (1974): Geological investigations in the 3) Impact of habitat on fauna: With generally Pasquia Hills area; Sask. Dep. Miner. Resour., good bone preservation at various localities in a Rep. 158, 16p. relatively restricted area, these uplands offer an opportunity to study habitat as a significant Bloch, J., Schroder-Adams, C.J., Leckie, D.A., variable in faunal studies. Mcintyre, O.J., Craig, J., and Staniland, M. ( 1993 ): Revised stratigraphy of the lower 4) Effects of the 94 my Oceanic Anoxic Event: Colorado Group (Albian to Turonian), Western Recognition in strata in the study area of the Canada; Bull. Can. Petrol. Geo!., v41 , p325-348. Oceanic Anoxic Event that occurred about 94 million years ago would allow us to address its Caldwell, W.G. E. , North, B.R., Stelck, C.R., and Wall, biotic significance. J.H. (1978): A foraminiferal zonal scheme for the 5) Abundance of birds and plesiosaurs: Further Cretaceous System in the Interior Plains of work is required to undertand why Cretaceous Canada; in Stelck, C.R. and Chatterton, B.D.E. marine faunas in our study area are characterized (eds. ), Western and Arctic Canadian by an abundance of birds and plesiosaurs. Biostratigraphy, Geol. Assoc. Can., Spec. Pap. 18, p495-575. 5. Acknowledgments Case, G. R., Tokaryk, T.T., and Baird, D. ( 1990): Selachians from the N iobrara Fonnation of the The authors wish to thank Dickson and Garth Hardie, Upper Cretaceous (Coniacian) of Carrot River, Ivan Hackett, and the L' Arrivee family for permission 62 Summary of Investigations 1999, Volume J Saskatchewan, Canada; Can. J. Earth Sci., v27, ____ ( 1989): An Odyssey in Time: The p !084-1094. Dinosaurs of North America; Univ. Toronto Press in assoc. with Nat. Museum ofNatur. Sci., 239p. Ells, S.C. ( 1923): Cretaceous shales of Manitoba and Saskatchewan, as a possible source of crude _____ (1993): Vertebrates in the Cretaceous petroleum; in Summary Report of investigations Western Interior Sea; in Caldwell, W.G.E. and made by the Mines Branch During the Calendar Kauffman, E.G. (eds.), Evolution of the Western Year Ending December 3 I, 1921 , Can. Oep. Interior Basin, Geo!. Assoc. Can., Spec. Pap. 39, Mines, p34-4 I . p665-680. Kauffman, E.G. (1984): Paleobiogeography and Russell, L.S. ( 1935): A plesiosaur from the Upper evolutionary response dynamic in the Cretaceous Cretaceous of Manitoba; J. Paleont., v9, p385-389. Western Interior Seaway of North America; in Westennann, G.E.G. (ed.), Jurassic-Cretaceous Tokaryk, T.T., Cumbaa, S.L., and Storer, J.E. ( 1997): Paleogeography of North America, Geol. Assoc. Early Late Cretaceous birds from Saskatchewan, Can., Spec. Pap. 27, p273-306. Canada: The oldest diverse avifauna known from North America; J. Vert. Paleont., v17, not, pl 72- Leckie, D.A., Singh, C., Bloch, J., Wilson, M., and 176. Wall, J. (1992): An anoxic event at the Albian Cenomanian boundary: The Fish Scale Marker Welton, 8.J. and Farish, R.F. (1993): The collector's Bed, northern Alberta, Canada; Palaeogeo. guide to fossil sharks and rays from the Cretaceous Palaeoclim., Palaeoecol., v92, p 139-166. of Texas; Before Time, Lewisville, Texas, 204p. Mcinnes, W. (1908): Pasquia Hills and lower Carrot Whiteaves, J.F. ( 1889): On some Cretaceous fossils River region; in Summary Report, Geo!. Surv. from British Columbia, the North West Territory Can., Sessional Pap. No. 26, p41-47. and Manitoba; Contrib. Can. Palaeont., v 1, p I 51- 196. McLearn, F.H. and Wickenden, R.T.O. (1936): Oil and gas possibilities of the Hudson Bay Junction area, Wickenden, R.T.D. {1945): Mesozoic stratigraphy of Saskatchewan: Preliminary Report; Can. Oep. the eastern plains, Manitoba and Saskatchewan; Mines, Bureau Econ. Geol., Geol. Surv. Pap. 36-8, Geol. Surv. Can. , Mem. 239, 87p. lip. Williams, G.L., Stover, L.E., and Kidson, E.J. (1993): McNeil, D.H. (1984): The eastern facies of the Morphology and stratigraphic ranges of selected Cretaceous System in the Canadian Western Mesozoic-Cenozoic dinoflagellate taxa in the Interior; in Stott, D.F. and Glass, D.J. (eds.), The northern hemisphere; Geol. Surv. Can., Pap. 92- Mesozoic of Middle North America, Can. Soc. 10, I 37p. Petrol. Geol., Mem. 9, p145-171. ____ (1992): Micropaleontology report on 18 Cretaceous outcrop samples from the Pasquia Hills area of eastern Saskatchewan (NTS 630, E); Geol. Surv. Can., Inst. Sed. Petrol. Geol., Rep. J-OHM- 1992 (unpubl. rep. prepared for T. Tokaryk). McNeil, D.H. and Caldwell, W.G.E. (1981): Cretaceous rocks and their Foraminifera in the Manitoba Escarpment; Geo!. Assoc. Can., Spec. Pap. 21, 439p. Nicholls, E.L. and Russell, A.P. (1990): Paleobiogeography of the Cretaceous Western Interior Seaway of North America: The vertebrate evidence; Palaeogeo., Palaeoclim., Palaeoeco., v79, pl49-169. Nicholls, E.L., Tokaryk, T.T., and Hills, L.V. (1990): Cretaceous marine turtles from the Western Interior Seaway of Canada; Can. J. Earth Sci., v27, p 1288-1 298. Russe ll, D.A. ( 1988): A check list of North American marine Cretaceous vertebrates including fresh water fishes; Occasional Pap. of the Tyrrell Museum of Palaeontology, No. 4, 57p. Saskatchewan Geological Survey 63