Berkey, Charles Peter, b. 1867.

Central Asiatic Expeditions (1921-1930)

Granger, Walter, 1872-1941.

American Museum of Natural History Scientific Publications

AMERICAN MUSEUM NOVITATESNumber 42 August 7, 192256. (117:-51.7)DISCOVERY OF CRETACEOUS AND OLDER TERTIARYSTRATA IN MONGOLIA'BY WALTER GRANGER AND CHARLES P. BERKEYThe American Museum commenced its natural history explorationsin Asia in 1916. The First and Second Asiatic Expeditions in charge ofRoy Chapman Andrews in 1916-1917 and 1918-1919, were engaged inzo6logical exploration and in laying the foundations for broader work.The Third Asiatic Expedition, sent out by The American Museum ofNatural History, the American Asiatic Association, and Asia Magazine,has included zo6logy, paleontology, geology, and geography under theleadership of Mr. Andrews, with Walter Granger as paleontologist,Charles P. Berkey as geologist and Frederick K. Morris as topographer,and other cognate lines of research may be taken up when the results ofreconnaissance warrant it.The scientific results of these expeditions will be published innumbered sequence as indicated below. The following reports or con-tributions have already been published:(No. 1) 'New Chinese Fishes.' By John Treadwell Nichols. Proc. Biol. Soc.Washington, XXXI, pp. 15-20, May 1&, MI1l.(No. 2) 'Description of a New Species of Serow from Yun-nan Province, China.'By Roy Chapman Andrews. American Museum Novitates, No. 6, March 24,1921.(No. 3) 'The Birds of The American Museum of Natural History's Asiatic ZoologicalExpedition of 1916-1917.' By Outram Bangs. Bull. Amer. Mus. Nat. Hist.,XLIV, Art. 20, pp. 575-612, December 30, 1921.(No. 4) 'Description of a New Loach from North-eastern China.' By Henry W.Fowler, American Museum Novitates, No. 38, May 25, 1922.RECONNAISSANCE EXPEDITION IN MONGOLIAOn April 21, 1922, the Third Asiatic Expedition left Kalgan, NorthChina, for its announced reconnaissance trip into Mongolia. It isplanned to devote the first three weeks of the season to observations alongthe regular caravan route between Kalgan and Urga, the capital ofMongolia, and- the rest of the season to points scattered far to the west,perhaps even as far west as Ulyosutai and Kobdo and the eastwardextension of the Altai mountains.'Contribution No. 5. Asiatic Expeditions of The American Museum of Natural History.AMERICAN MUSEUM NOVITATESThe chief effort of the present season is to be devoted Jo geology,palaeontology, geography, and zoology, but other scientific interests willbe cared for in subsequent seasons if the reconnaissance warrants suchexpansion. It is believed that fields inviting more extended and detailedwork will be discovered and that the reconnaissance will furnish a basisfor final plans and indicate the nature of the problems that promise bestresults.At the close of the season President Henry Fairfield Osborn is ex-pected to join the expedition staff at the headquarters in Peking and willtake an important part in the conferences in which plans for the next threeyears w ll be formulated.The scientific staff on the present reconnaissance includes RoyChapman Andrews, zoologist, Walter Granger, palaeontologist, CharlesP. Berkey geologist, and Frederick K. Morris, physiographer.It is hoped that there may be opportunity to send short notes ofobservations or discoveries of special interest directly from the field but,in any case, a summary of the season's results will be issued with littledelay on the return of the Expedition.CRETACEOUS STRATA IN EASTERN AsIA.-The Third Asiatic Expedi-tion announces, under date of May 3, 1922, that strata of Cretaceousage, overlain by two distinct Tertiary formations, have been discoveredin the Gobi region of southeastern Mongolia.They were found on the outbound trip from Kalgan to Urga at apoint about 260 miles northwest of Kalgan. Strata of Cretaceous age arewholly unknown in Eastern Asia, as far as the writers are aware, and be-cause of the apparent importance of the find, it was decided to leave thegeologists in camp at this place while the rest of the party moved on.Accordinglv Messrs. Berkey, Granger, and Morris spent a week in addi-tional inspection of the ground and furnish the notes for this memoran-dum.Th best exposures of the Cretaceous formation are in the vicinity ofthe small salt marsh Iren Dabasu, where a total thickness of about 150feet of nearly horizontal strata is judged to be of this age. Tertiary bedsnot older than the Miocene lie on top of the Cretaceous strata and arebest exposed about five miles south of Iren. Twenty miles farther southearly Tertiary beds were found in essentially the same relation.In each occurrence of the Tertiary beds only a single horizon hasfurnished determinative fossils, but in the Cretaceous formation below,there are at least two fossil bone-bearing horizons. Fortunately thefaunal evidence is unmistakable. Otherwise the widely different age2 [No. 421922] CRETACEOUS AND TERTIARY IN MONGOLIArela*ions of the strata would not be suspected, for the correspondingphysical breaks are inconspicuous and the beds are almost perfectly con-formable.The structural basin in which these strata lie measures forty milesacross from north to south and is floored with ancient slates and lime-stones of extremely complicated deformation structure. This is only oneof six basins of similar form and relation between Kalgan and Iren but itis much the longest one and the only one in which, thus far, the presenceof strata of Cretaceous age has been proven.In the vicinity of the small salt lake Iren Dabasu, the Cretaceousbeds lie immediately on the slate floor of the basin and between this baseand the first determinable beds of later age, in this case late Tertiary,about 150 feet of strata are exposed. The bottom members are domi-nantly sands and sandstones, prevailingly thin-bedded, some of whichare strongly cross-bedded and well cemented. The middle members be-come finer grained, more miixed with clay and more variable in color.The upper beds are dominantly clays and sandy clays and very fine sands,varyifg in color from white to dark red and drab and yellowish green.No less than twenty distinct beds or layers can thus be distinguished,all of which are regarded as belonging to a single geologic formation.Only the lower members of this formation have been found to befossiliferous. The list includes:1.-Predentate dinosaurs, probably of the bipedal type.2.-Carnivorous dinosaurs of at least two genera, the smaller onebeing of the Ornithomimus type.3.-Crocodiles.4.-Turtles of the Trionyx type.5.-A few pelecypod shells.Obretcheff, the Russian geologist, who gives an account of a recon-naissance trip over this same route from Ude to Kalgan, describes sedi-mentary beds at many places, always referring to them as representa-tives of the Gobi formation. His only age determination, however, wasmade on the basis of a few fragments of Rhinoceros, found at the escarp-ment five miles south of Iren. These remains were judged by EduardSuess, to whom they were referred, to indicate an age not earlier than theMiocene. The Tertiary age of the rest of the occurrences mentioned byhim seems to have been taken for granted and apparently that is ingeneral correct, but it is evident that the Gobi formation cannot properly3AMERICAN MUSEUM NOVITATESinclude strata of both Tertiary and Cretaceous ages. It is clear also thatthe term Gobi formation or Gobi series is properly applied to the Tertiarybeds instead of to those of Cretaceous age. The finding of a Cretaceousformation below makes a new designation necessary. For this purposenothing seems to be as appropriate as the name of this locality. Wetherefore propose the term IREN DABASU FORMATION for these beds.90 0 e1 u2% '!CO'R°440Irer9 babasuGo bi Oeser+i3GSc*es of Mites9 59 0 %S0) 200500Fig. 1. Sketch map showing location of type sections of Irp Dabasu Formation. (Cietaceoua)l;Irdin Manha Formation (Eocene) 2; Houldjin Formation (Mipcene) 3.THE HOULDJIN BEDS (MIDDLE TERTIARY).-For the late Tertiarybeds found five miles farther south and belonging to the Gobi Series ofObretcheff we propose the term HOULD.TJN BEDS, taken from the localname of the upland formed by these beds. They are characterized by thefollowing fossil content:1.-A rhinocerid.2.-A large carnivore.3.-An artiodactyl of the size of a Virginia deer.4.-An enormous mammal, probably a perissodactyl and possiblyrelated to or identical with Baluchitherium, discovered by Forster Cooperin Baluchistan.5.-A tortoise of large size.4 [No. 4219221 CRETACEOUS AND, TERTIARY IN MONGOLIAThere is a sharp physical change immediately below this formationand only the coarse sandy conglomeratic member at the very base has beenfound to be fossiliferous. The fossil remains are unusually fragmentary.IRDIN MANHA FORMATION (EARLY TERTIARY).-For the earlyTertiary beds found twenty-five - miles farther south, also assumedproperly to belong to Obretcheff's Gobi Series, we propose to use theterm IRDIN MANHA FORMATION. It appears to lie immediately on Cre-taceous beds, the Iren Dabasu formation, and again there is a sharpchange in type of rock. The beds are cross-bedded sandstones, limysands and pebbly sandstones. Only the lower member has been found tobe fossil-bearing. It is characterized by the following forms:1.-Small Lophiodonta of at least two species in great abundance.2.-A perissodactyl about the size of the Upper Eocene titanotheresand possibly related to this family.3.-A small artiodactyl.4.-A small creodont.5.-An abundance of turtles of both the hard-shelled and Soft-shelled groups.6.-Teleost fishes.The geologic column for the Iren Dabasu basin therefore is essen-tially as in the following table.Recent Uplift and Erosion-_____ PeneplanationMiocene or Upper barren sands 25'+ The HouldjinLater Rhinoceros gravels 5' Formation The GobiTertiary Oligocene or Upper barren sand- 25'+ The Irdin SeriesEocene stones ManhaThe Lophiodont bed 4' FormationPhysical and Faunal Break _Upper barren members, chiefly clays,marls and fine sands 90' The IrenCretaceQus DabasuLower or Dinosaur beds, chiefly sands 60' Formationand sandstonesGreat unconformityPre- The old-rock floor, chiefly slates, ProbablyCretaceous limestones and igneous rocks The Nank'-on Series5AMERICAN MUSEUM NOVITATESVERTEBRATE FOSSILS, ADDITIONAL DETAILS.'-Remains in all threebeds are fragmentary, decidedly so in the Houldjin grave's, but theyare of unusual interest apparently and we have taken everything whichhas any character. Dinosaurs are reprecented by one complete tibia,ends of femora and humeri, presacral and caudal centra, many good footbones, including claws of fore and hind feet, portions of a small carnivor-ous dinosaur skull with two or three teeth, and two teeth of a predentate,as well as two portions of jaw with the alveoli of some teeth, alsopredentate. Remains of the small Ornithomimus-like creature areparticularly abundant and the last day at Iren Dabasu we picked upprobably fifty good foot bones and centra from two or three knolls. Wecould find no teeth of the little fellow though-wonder if he was edenta-tate like Struthiomimus ? The Cretaceous exposures are very limited so faras we could see but may, of course, outcrop in other basins to the eastor west of the road. We did not have time to extend our work in eitherdirection. The outcrops we did see will stand a more careful going over.The Houldjin gravels are exposed as a rather thin capping to a lowbench of Cretaceous which we followed for several miles. Things arebadly broken up here-even such massive bones as the heads of femoraand humeri were usually cracked into several pieces before deposition.There is one fine bone-a calcaneum of the big beast which would be a.match for the astragalus of Baluchitherium2 (?). I can think of nothingelse to which it might belong. It is as long as the great Megatheriumcalcaneum from Long Branch, N. J., but is not edentate. A head of afemur is the size of one's head and other limb bone ends correspond.Some enormous rhinoceros teeth (broken) may belong with this animal.Smaller teeth are surely Rhinoceros. We did not explore the full length ofthe exposure and there are possibilities in excavation at one or two pointsof the bluff where we did explore.The Irdin Manha beds offer the greatest opportunity for future work.Mammal'an remains are abundant though fragmentary and we examinedless than two miles of a line of exposures extending many miles both eastand west of the trail. A small lophiodont (Helaletes-like) is most abund-ant and we got numerous teeth besides two maxille (one with premaxillaand orbital region) and a few lower jaws, also numerous oot bones,limb bones and vertebrae. Next in abundance is a perissodactyl, lookingmuch like our late Eocene titanotheres. We have several premolars,many incomplete molars and one lower jaw with p3-m3 in fair condition.'Communicated in a letter by Mr. Walter Granger, dated May 10, 1922.2A gigantic perissodactyl described by C. Forster Cooper from Baluchistan.6 [No. 4219221 CRETACEOUS AND TERTIARY IN MONGOLIA 7Other forms are curiously rare, a creodont lower jaw and an artiodactylastragalus or two being the only things noted. Trionychids are commonand we saw a complete though badly broken carapace which we werehurrying to get to our car before a storm overtook us the last day wewere there. We made three trips down from Iren Dabasu camp butcould not do more as our food was getting short and we had to join therest of the party here.Much additional detail is in possession of the Expedition whichwill appear in due course, and it is expected also that further investiga-tion of this area and related ones will be made at a later time.THE THIRD ASIATIC EXPEDITION.

Cretaceous and Tertiary in Mongolia

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