DEPABTMENT OF THE INTEKIOR BULLETIN OF THE UNITED STATES GEOLOGICAL SURVEY N~o. 151 WASHINGTON GOVERNMENT PRINTING OFFICE 1898 UNITED STATES GEOLOGICAL SURVEY CHARLES D. WALCOTT, DIEECTOR THE LOWER CRETACEOUS GRYPMAS OF THK TEX.AS REGION ROBERT THOMAS HILL THOMAS WAYLA'ND VAUGHAN WASHINGTON GOVERNMENT FEINTING OFFICE 18.98 THE LOWER CRETACEOUS GRYPHJ1AS OF THE TEXAS REGION. BY I EOBEET THOMAS HILL and THOMAS WAYLAND VAUGHAN. CONTENTS. Page. Letter of transmittal....._..........._....._ ............................ 11 Introduction ...---._._....__................._....._.__............._...._ 13 The fossil oysters of the Texas region.._._.._.___._-..-._._......-..--.... 23 Classification of the Ostreidae. .. ...-...---..-.......-.....-.-............ 24 Historical statement of the discovery in the Texas region of the forms referred to Gryphsea pitcher! Morton ................................ 33 Gryphaea corrugata Say._______._._..__..__...__.,_._.________...____.._ 33 Gryphsea pitcheri Morton............................................... 34 Roemer's Gryphsea pitcheri............................................ 35 Marcou's Gryphsea pitcheri............................................ 35 Blake's Gryphaea pitcheri............................................. 36 Schiel's Gryphsea pitcheri...........................,.:................ 36 Hall's Gryphsea pitcheri (= G. dilatata var. tucumcarii Marcou) ...... 36 Heilprin's Gryphaea pitcheri.....'..................................... 37 Gryphaea pitcheri var. hilli Cragin.................................... 38 Differentiation .............................................._............ 38 Gryphsea washitaensis Hill........................................... 41 Gryphseanewberryi Stanton.......................................... 41 Gryphaea gibberosa Cragin ........................................... 42 Geographic and stratigraphic distribution of the Lower Cretaceous gryphseas 43 Specific classification and evolution of the Lower Cretaceous gryphaeas...- 46 Description of species ...^................................................. 49 Gryphsea wardi, sp. nov....----...--..--...-.--.......... .....'....... 49 Gryphaea marcoui, sp. nov .......................... ........ .......... 50 Gryphsea corrugata Say (gen. nov. ==GK corrugata Hill) ............... 53 Gryphsea navia Hall .................................................. 57 Gryphsea washitaensis Hill........................................... 59 Gryphsea mucronata Gabb............................._....._......... 63 Relationship and evolution of the gryphseas............................... 65 7 ILLUSTRATIONS. Page. PLATE I. Gryphaea wardi, sp. nov ..__...._..__.-.--........._...-. ...... 70 II. Gryphsea marcoui, sp. nov__._._....__----.---......_---.-....--. 72 III. Gryphsea marcoui, sp. nov................................... ... 74 IV. Gryphaea marcoui, sp. nov., adult forms ...._._........-.....-.- 76 V. Gryphsea marcoui, sp. nov., and Gryphaea corrugata Say........ 78 VI. Gryphsea corrugata Say ....................^................... 80 1 VII. Gryphsea corrugata Say, tipper valves--------....--.---_..-.-.. 82 1 VIII. Gryphsea corrugata Say, various. ................................. 84 IX. Gryphsea corrugata var. belviderensis.............--...--.--.-.- 86 X. Gryphsea corrugata Say, var. belviderensis, maximum size....... 88 r, XL Gryphsea corrugata Say, from Kansas, showing variation........ 90 XII, Gryphsea corrugata Say, from Kansas, showing variation ... 92 XIII. Grypheea corrugata Say, var. tucumcarii, from New Mexico..... 94 XIV. Gryphsea corrugata Say, var. tucumcarii, from New Mexico, max­ imum size ----_-------.--.--.___.-.-...-----._.--..-------.-.. 96 XV. Copies of Hall's figures of G. corrugata Say, described as G. pitcheri Morton ........ ...................................... 98 ( XVI. Reproduction of Marcou's figures of G. dilatata (Gryphsea cor­ rugata Say) .........._.................-...................... 100 XVII. Reproduction of Marcou's figures of G. navia Hall, G. tucumcarii Marcou. and Ostrea subovata Shumard............ ........... 102 XVIII. Gryphsea navia Hall............................................. 104 XIX. Gryphsea corrugata Say, and Gryphsea washitaensis Hill........ 106 XX. Gryphaea wushitaensis Hill; lower valves ....................... 108 XXI. Gryphsea washitaensis Hill; old form showing maximum develop­ ment ...--...-..-.--..........-..--...-..-...-....--...-...-..... 110 XXII. Gryphsea washitaensis Hill; old form showing maximum develop- ' ment......................................................... 112 / XXIII. Gryphaea washitaensis Hill and Gryphaea mucronata Gabb...... 114 XXIV. Gryphsea mucronata Gabb; stages of development........ ...... 116 XXV. Gryphsea mucronata Gabb; normal lower valves................ 118 XXVI. Reproductions of Roemers Gryphsea pitcheri (G. mucronata), illustrating free specimens, and figures showing attached forms. 120 1 XXVII. Variation of Gryphsea mucronata; elongate forms .............. 122 " XXVIII. Variation of Gryphaea mucronata Gabb; normal forms.......... 124 XXIX. Variation of Gryphsea mucronata Gabb; triangular forms....... 126 XXX. Variation of Gryphsea mucronata Gabb; attached forms ........ 128 XXXI. A bed of living oysters on Georgia coast........................ 130 XXXII. Columnar section near Denison, Texas, showing stratigraphic occurrence of fossil Ostreidse................................... 132 XXXIII. Columnar section near Fort Worth, Texas, showing occurrence T of fossil Ostreidse............................................. 134 .XXXIV. Columnar section near Weatherford, Texas, showing occurrence ' of fossil Ostreidse.............................................. 136 XXXV. Columnar sections of Texas region, showingoccurr ence of fossil Ostreidse ..................................................... 138 FIG. 1. Hinge of lower valve of G. washitaensis, nepionic stage............ 61 2. Diagram showing the probable evolution of the Gryphsea of the v Comanche series............................................... 65 9 LETTER OF TRANSMITTAL. DEPARTMENT OP THE INTERIOR, UNITED STATES GEOLOGICAL SURVEY, Washington, D. C., January IS, 1897. ' SIR: I transmit herewith, for publication, a paper entitled The Lower Cretaceous Gryphseas of the Texas Region, which has been prepared jointly by Mr. Thomas Wayland Vaughah, assistant geolo­ gist, and myself. Very respectfully, ROBT. T. HILL, G-eologist. To THE DIRECTOR, United States Geological Survey. 11 THE LOWER CRETACEOUS GRYPH.EAS OF THE TEXAS REGION. By ROBERT T. HILL and T. WAYLAND VAUGHAN. INTRODUCTION. The present paper treats of the specific classification, stratigraphic occurrence, and relationships of one particular group of the many kinds of fossil oysters occurring in the Lower Cretaceous formations of Texas. This group includes those forms which have generally been referred to G-ryphcea pitcheri of Morton. Owing to the plentiful occurrence of the shells of these oysters in the formations mentioned, this group is of great importance from many standpoints, and a thor­ ough knowledge of the forms composing it has the utmost economic value because of the assistance which they render in determining the stratigraphic position of various beds in the geologic sections. In two ^stances within the last year, by the aid of these fossils, brought up, from great depths in diamond-drill cores, cities in Texas upon the point of abandoning the attempt to procure artesian water have been warranted in drilling a few feet farther, where the desired artesian flow was procured. Unfortunately, however, this group of fossils has not been properly understood or classified, owing to the inadequate manner in which they were originally described and pub­ lished. These descriptions were often based upon single specimens or incomplete collections made in the hasty reconnoissances of early frontier expeditions and were unaccompanied by stratigraphic data. The species from the Texas region have usually been based upon one or two poor specimens, accidentally picked up without record of strati- graphic occurrence, and described by a paleontologist unacquainted with the stratigraphic relations of the rocks in which they were found. Other species have been made from variations of some previously described form. The forms have also become involved in a confusion of nomenclature and controversy, so that the student can not obtain from the literature a proper conception of their occurrence, distribu­ tion, and classification. A controversy between Prof. Jules Marcou on the one hand and nearly all the eminent American paleontologists of the day on the 13 14 LOWER CRETACEOUS GRYPH^EAS OF TEXAS REGION. [BULL. 151. other early arose concerning the species G-ryphc&a pitcheri and the formations in which it was found. Upon the finding at Tucumcari Mesa, New Mexico, of two fossil oysters which he termed G-ryphc&a dilatata var. tucumcarii and Ostrea marshii (Marcou, not Sowerby), Professor Marcou announced the existence there of rocks of the Ju­ rassic age. He likewise asserted .the existence of Lower Cretaceous strata at Comet Creek, on the head waters of the False Washita, a locality in what is now known as Oklahoma, basing this conclusion upon the existence of a single species of fossil oyster in strata of luma- chelle limestone aggregating only a few feet in .thickness. Professor Marcou in his many papers has variously described these beds and their thickness, and has successively referred this species as follows: " Exogyra