Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Geological Society of America Bulletin

Mount Jura Investigation

C. H. CRICKMAY

Geological Society of America Bulletin 1933;44, no. 5;895-926 doi: 10.1130/GSAB-44-895

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Notes

© 1933 Geological Society of America Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA

V O L . AA, PP. 895-926. PLS. 23-34 OCTOBER 31. 1933

MOUNT JURA INVESTIGATION 1 BY C. H . CRICKMAY

(Presented before the Geological Society, December 30,1982) CONTENTS Page Introduction ...... 895 Acknowledgments ...... 895 General and structural geology 895 Stratigraphie summary 896 Description of species. 903 Explanation of plates. 915

I ntroduction Since 1927 the writer has been engaged in a study of the stratigraphy, structure, and paleontology of Mount Jura, California, undoubtedly the finest Jurassic section in North America. Elucidation of the stratigraphy has been made extremely difficult by the complexity of the geologic struc­ ture of the mountain. The work is now complete, however, and a mono­ graph on the geology and paleontology is being written. Since it may be some years before that monograph can be issued, this article is published as an advance summary of results.

A cknowledgments The writer is under deep obligations to the University of California and to the National Research Council for generous financial aid, without which the drain on his private funds would have been unbearably heavy. Dr. T. W. Stanton and, later, Dr. J. B. Reeside, have been very kind in extending the hospitality and technical services of the United States Na­ tional Museum and the United States Geological Survey. Francis E. Dreyer, A. B., assisted in the field in 1929, and Leland H. Dykes, A. B., in 1931. More adequate acknowledgments will be made in the monograph.

Ge n e r a l a n d S t r u c t u r a l G eology Mount Jura consists of highly disordered Triassic and Jurassic rocks. These have been severed by faults and piled repeatedly upon one another, producing a very complicated, imbricated structure. This structure,

1 Manuscript received by the Secretary ot the Society, January 30, 1933. (895) Downloaded from gsabulletin.gsapubs.org on November 18, 2014

896 C. H. CKICKMAY----MOUNT JUBA INVESTIGATION

which long baffled solution, is made up of a network, or braidwork, of faults, separating imbricated, lance-shaped selvages of various formations. Some of these selvages are overturned. The whole imbricated mass has been hoisted up on the west side, where the oldest rocks in it—the Triassic—are now exposed. In a compensating manner it has been forced down on the east side, where the youngest rocks—the Upper Jurassic— are found. The whole imbricated mass is enclosed by older rocks which have been thrust against it and upon it from both east and west. The overthrust rocks on the east side are of Carboniferous age; those on the west are mostly early Paleozoic. The two thrust faults are opposed to one another in regard to direction of faulting. It may be noted that no other opposed thrusts of this sort seem to have been observed in the structure of the Sierra Nevada, and very few elsewhere.

S tratigraphic S u m m a r y Jurassic epigene formations (descending order) : Combe sandstone Trail tuff and conglomerate Lucky S argillite Cooks Canyon agglomerate Forman argillite North Ridge argillite Hinchman arkose Hull agglomerate Moonshine conglomerate Mormon sandstone Thompson tuff Fant volcanics Hardgrave arkose Lilac sandstone As the determination of the Jurassic column is the outstanding result of this work, attention will be confined to the Jurassic epigene deposits in this advance summary. Description of intrusive formations and of de­ posits of other ages must await a later opportunity. The epigene deposits, including on an equal footing both the sedimentary and the volcanic, are here described briefly, beginning with the oldest.

L il a c F o r m a t io n Name.— New. Occurrence.— At various separate localities along the west base of ' Mount Jura and elsewhere. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

STRATIGRAPHIC SUMMARY 897

General character.— Calcareous, dark-gray sandstone and argillite. Thickness.— 725 feet. Fauna.— Upper zone : Parapecten praecursor n. sp. Lower zone : Euechioceras exoletum n. sp. Age.— Mid Lower Jurass'c; upper zone, Grammoceratan ; lower zone, Deroceratan, Euechioceras. Relations.— The Lilac formation rests on the Middle Triassic vol- eanics, the oldest rocks in the Mount Jura column.

H ardgrave F o r m a t io n Name.— Given by J. S. Diller, 1892. Occurrence.— Most abundant in narrow bands across lower west slope of Mount Jura. General character.— Eed, stratified, marine, volcanic arkose, highly fossiliferous. Thickness.—-150 feet. Fauna.— Cidaris taylorensis Clark C. plumasensis Clark Gervillia gigantea Hyatt 6. linearis Hyatt Pinna expansa Hyatt Entolium meeki Hyatt parapecten acutiplicatus Meek Trigonia sp. "Dumortieria” sp. bispinosa Glyphaea punctata Hyatt Age.—Earliest Middle Jurassic, Ludwigian,------.

F a n t F o r m a t io n Name.— Given by J. S. Diller, 1892. Occurrence.— In broad, prominent bands across west side of Mount Jura and elsewhere. Stands up in cliffs in many places. General character.—Massive, coarsely porphyritic andesite lavas (green) and crystal tuffs (red). Thickness.— 900 feet. Fauna.— None. Age.—Early Middle Jurassic.

T h o m p s o n F o r m a t io n Name.— Given by J. S. Diller, 1892. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

89 8 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

Occurrence.— In several narrow bands across west slope of Mount Jura, especially about 4200 to 4400 feet elevation on Mill Ravine, near the Knob and near the old Thompson farmhouse. General character.— Mainly a fine, red, stratified marine tuff, with some thick lenses of pale blue-gray limestone. Thickness.— 115 feet. Fauna.— Ptyctothyris n. sp. Nerinea thompsonensis n. sp. Age.—Early Middle Jurassic; Sonninian (?),------.

Mormon F ormation Name.— Given by J. S. Diller, 1892. Occurrence.— In several bands lying across west slope of Mount Jura, one band lying up and down southeast slope. General character.— Mainly fine gray arkose, with red and green con­ glomerate of volcanic debris at the base, and fine, dark gray paper shales at top. Thickness.— 943 feet. Fauna.— Several successive faunas occur. In descending order, num­ bered from the bottom up, these are: (11) Posidonomya sp.

(10) Teloceras sp., trephomorph

(9) Rhactorhynchia n. sp. Ornithella, n. sp. Scaphogonia n. sp.

(8) Scaphogonia n. sp. Haidaia n. sp. Papilliceras juramontanum n. sp. Chondroceras sp.

(7) Holcophylloceras falciferum n. sp. Papilliceras blackwelderi n. sp. Otoites reesidei n. sp. Chondroceras russeUi n. sp. “Trigonia" pandicosta Meek Astarte ventricosa Meek

(6) Trigonia cf. sculpta Lycett Haidaia sp. Entolium aff. gingense Quenstedt Downloaded from gsabulletin.gsapubs.org on November 18, 2014

STRATIGRAPHIC SUMMARY 899

(5) Kallirhynchia sp. indet. Flabellirhynchia sp. Q-lobirhynchia n. sp. O. ffnathophora Meek Loboidothyris n. sp. PapilUceras stantoni n. sp.

(4) Globirhynchia sp. Loboidothyris n. sp. Haidaia n. sp. StiphromorpMtes schucherti 11. sp.

(3) KattirhyncMa n. sp. Flabellirhynchia n. sp. Euidothyris n. sp. Entoiium equabile Hyatt Haidaia n. sp. Lima dilleri Hyatt (2) Flabellirhynchia sp. Camptoneotes aff. lens Sowerby (1) Latomeandra orthogrammica n. sp. There are also a number of species of Meek and of Hyatt not allocated to their proper zones: Cidaris califomicus Clark Hemicidaris intwmescens Clark Pseudodiadema emersom Clark Stomechinus hyatti Clark Pinna ouneiformis Hyatt Lima taylorensis Hyatt Mytilus multistriatus Meek Pleuromya depressa Meek Age.—Early Middle Jurassic: Faunas 1 to 3 ...... Sonninian, pre-mollis 4 ...... “ mollis 5 ...... “ Labyrinthoceras 6 ...... “ sauzei 7 ...... “ alsatica 8 ...... Stepheoceratan, Masckeites

9 ...... “ EpdUsites 10 and 11...... “ banksii Relations.—Disconformable on both the Thompson and the Pant for­ mations; overlain disconformably by the Moonshine formation. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

90 0 C. H . CBICKMAY---- MOUNT JURA INVESTIGATION

M o o n s h in e F o r m a t io n Name.—New, of geographic origin. Occurrence.—Most abundant on southwest slope of Mount Jura, just below 4500 feet elevation. General character.—Lower part, an ordinary conglomerate bearing cobbles of granitic plutonic origin and ancient red porphyries, grading upward into red conglomerates, red shale, and finally red tuffs. Thickness.— 300 feet. Fauna.—None found during this investigation. However, Diller reports: “Terebratula” sp. Inoceramus sp. Perisphinctes sp.

It is possible, of course, that Diller was mistaken in supposing that he had found these in this deposit. Age.—Mid Middle Jurassic.

H u l l F o k m a tio n Name.— Given by J. S. Diller, 1892. Occurrence.—At many places on the slopes of Mount Jura, especially on the south end of the mountain, on the southwest slope from 4500 to 5000 feet elevation, in the lower end of Hinchman Eavine, southeast and northwest slopes of the mountain, and north ridge. Usually prominent as a cliff-maker. General character.—Mostly massive, coarse, green agglomerate, with small amounts of red and purple matter; in places, a fine red or a green tuff. Thickness.— 700 feet. Fauna.— None. Age.—Late Middle Jurassic.

H i n c h m a n F or m a t io n Name.— Given by J. S. Diller, 1892; extended to cover Diller’s “Bick- nell formation” also. Occurrence.—West fork of Hinchman Eavine (type locality), south­ east slope of Mount Jura, north ridge, and elsewhere. General character.—In its lower part, a coarse arkose-breccia; in its upper, a medium to very fine arkose. Mainly composed of volcanic waste. Thickness.— 160 feet. Fauna.—Upper zone: Downloaded from gsabulletin.gsapubs.org on November 18, 2014

STEATIGRAPHIC SUMMARY yoi

Oxytoma sp. “Trigonia” obliqua (Hyatt) Packard “Trigonia” plumasensis (Hyatt) Packard “Trigonia” naviformis (Hyatt) Packard Gryphaea bononiformis Hyatt Pleuromya sp. Ptychophylloceras sp. (=RhacophyUites sp. Hyatt) “Macrocephalites” sp.

Lower zone:

Astrocoenia minuta Hyatt A. suhjeeta Hyatt Stephanocoenia tertia Hyatt Gnathorhynchia n. sp. “Rhynchonelloidea” n. gen. and sp. Ornithella n. sp. Camptonectes cf. platessiformis White Gryphaea curtici Hyatt “Trigonia” aff. plumasensis Hyatt Trochus hinchmanensis n. sp. Phylloceras burokhardti n. sp., etc.

Age.—Early Upper Jurassic; Proplanulitan,------.

N orth Ridge F ormation Name.—New, of geographic origin. Occurrence.—Hinchman Ridge and Ravine, north ridge of Mount Jura (type locality), and elsewhere. General character.—A crudely stratified, pyroclastic agglomerate of medium grain and basic composition; color, dark gray, speckled white. Thickness.— 200 feet. Fauna.— Very scarce.

Anaplanulites hyatti n. sp.

Age.—Early Upper Jurassic; Proplanulitan, Catacephalites?

F orman F ormation Name.— Given by J. S. Diller, 1892. Occurrence.—At Taylor’s Diggings, in south fork of Forman Ravine, and elsewhere. General character.—Light gray argillite composed of fine volcanic waste. Thickness.—350 feet. Fauna.—Upper zone: Downloaded from gsabulletin.gsapubs.org on November 18, 2014

9 0 2 C. H. CRICKMAY--- MOUNT JURA INVESTIGATION

“Trigonia” aff. naviformis Hyatt Protocardia cf. subsimilis Whiteaves Cinulia cf. pusiUa Whiteaves Reineclceites dilleri n. sp. R. n. sp.

Lower zone: “Trigonia” aff. plumasensis Hyatt Oyprimeria sp. Remeckeia cf. subtilis Burckhardt Age.—Early Upper Jurassic; Reineckeian,------.

Cooks Canyon F ormation Name.—New, of geographic origin. Occurrence.— Ridge between Cooks Canyon and Lights Creek (type locality), near Forman farmhouse, Forman Ravine, Forman Ridge, and elsewhere. General character.—At type locality, mostly red agglomerates, contain­ ing here and there fossil charcoal of coniferous wood and angular frag­ ments from the mid Upper Jurassic intrusive quartz porphyry; in For­ man Ravine and neighborhood, mostly coarse, water-laid, elastic sediment of volcanic origin, gray to green in color, containing here and there fossil charcoal of coniferous wood. Thickness.— 1900 feet at Cooks Canyon; 900 feet at Forman Ravine. Fauna.— None. Flora.— Only unidentifiable charred coniferous wood. Age.—Mid Upper Jurassic.

Lucky S F ormation Name.— New, after Lucky S Mine. Occurrence.—Forman Ravine, west end of Forman Ridge (type local­ ity), in Cooks Canyon and in Starks Ravine. General character.— Micaceous quartzite, with one or more fine con­ glomerates of chert and quartzite pebbles derived from much older de­ posits; grading upward into micaceous, dark gray siltite and black argillite. Thickness.— 600 feet. Fauna.—Yery meager marine fauna in upper beds; no identifiable fossils.

Age.-—Mid Upper Jurassic. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

STRATIGKAPHIC SUMMARY 903 \

Trail F ormation Name.— Given by J. S. Diller, 1892. Occurrence.— Hosselkus Canyon, Forman Ravine, Cooks Canyon, and Evans Peak. General character.— Alternating beds of conglomerate and fine tuff, each several feet to 100 feet or more in thickness. The tuff beds are chiefly gray in the lower part of the formation and red in the upper; a distinguishing mark is the presence of many small, irregular cavities lined with a dark green mineral. Thickness.—2000 ± feet. Fauna.— None. Age.—Late(?) Upper Jurassic.

Combe F ormation Name.—New, of geographic origin. Occurrence.— Combe Canyon, north of Mount Jura. General character.— A calcareous marine sandstone and conglomerate containing cobbles from the mid Upper Jurassic quartz porphyry and from granitic plutonics. Thickness.— 550 feet. Fauna.— Rich, though ill-preserved: Phyllocoenia cf. nannodes Felix Stylina sp. Kailirhynchia n. sp. Terebratulvna n. sp. Argyrotheca n. sp. Lima cf. comatulicosta Felix Astarte sp. Aulacosphinctoides sp. Age.—Late Upper Jurassic, Tithonian.

D escription of S pecies Phylum COELENTERATA Class ZOANTHARIA Family ORBICELL1DAE Genus LATOMEANDRA D’Orbigny LATOMEANDRA ORTHOGRAMMICA n. sp. (Plate 23, figures 1-3) Description.— Corallum, large, spreading, with flat surface; sides, not seen. Septa, insert, numerous, fine, irregular. Endotheca, not seen.

LIX—B u l l . Geo l. Soc. A m ., Vol. 44, 1033 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

9 0 4 C. H. CRICKMAY----MOUNT JURA INVESTIGATION

Calyx very shallow. Corallites, small, set in straight rows which are bordered by fine sharp ridges of exotheca. Dimensions.— Width of corallites...... 4 mm., invariable Length of corallites...... 6 mm., very variable, from 4 to 12 mm. Locality.—Southwest side of Mount Jura, Ravine 34 at 4300 feet. Zone.—Mormon formation, orthogrammica zone.

Phylum MOLLUSCA Class PELECYPODA Family PINNIDAE

Genus PINNA Linnaeus PINNA EXPANSA Hyatt (Plate 24, figure 1) Description.— Shell, of medium size, broad, flattish, ornamented with 12 strong radial striae in the upper half of the disk, marked only with coarse growth lines in the lower half; beak, not seen; sulcus, very long, narrow. Locality.—Not known. Coll. I. C. Russell, probably at loc. 523. Zone.— Hargrave formation.

Family PECTINIDAE Genus ENTOLIUM Meek ENTOLIUM EQUABILE Hyatt Ms. (Plate 24, figures 4-6) Oliironym first published in G. M. Dawson: Report on the area of the Kamloops Map-sheet, Geol. Surv. Canada, Ann. Rept., 1895, vol. 7. Description.— Shell, small, highly orbicular except for a weak, obtusely angular distension on the postero-dorsal margin, smooth; ears, small. Dimensions.— Length ...... 21 mm. Height ...... 24 mm. Semidiameter ...... 4.2 mm. Upper edge of ears ...... 4 mm. Apical angle ...... 110° Angle between ears ...... 145°

Locality.— Coll. J. S. Diller, loc. 2429, northwest spur of Mount Jura, 4800? feet. Zone.— Mormon formation, zones 3 to 5. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

DESCRIPTION OF SPECIES 905

ENTOLIUM MEEKI Hyatt 1893 (Plate 24, figures 2 and 3)

Description.— Shell, suborbicular, ilattish, smooth except for marked concentric rippling on the umbo; ears, of medium size.

Dimensions.— Length ...... 32 mm. H eig h t...... 36 mm. Semidiameter...... 5(?) mm. Upper edge of e a r s...... 8 mm. Apical angle ...... 108° Angle between ears...... 170°

Locality.— Coll. I. C. Russell, loc. 523, % mile east of Taylorsville. Zone.—Hardgrave formation.

Genus PARAPECTEN Crickmay PARAPECTEN PRAECURSOR n. sp. (Plate 25, figures 4-6)

Description.— Shell, small, covered with fine, regular, concentric lamel­ lae; right valve, very highly arched, ornamented with 15 or 16 strong radial ribs which are acute on the umbo but flat on the disk, smooth in­ ternally except next to the margin which is lirate; ears of right valve, without ornament except the fine lamellae; byssal notch, medium-shallow depth; ctenolium, not seen but seemingly developed because traces of some such structure are preserved in the form of spiral volutions on the angle between the right anterior ear and the internal surface of the valve; left valve, flattish, very gently arched in the upper half of the disk, orna­ mented with 15 or 16 strong, acute radial ribs which though sharper are less elevated than those of the right valve, lirate internally; ears of left valve, large, squarish, ornamented with two radial ribs, one at, the other near, the cardinal margin. Hinge teeth and chondrophore, not seen.

Dimensions.— Length ...... 60 mm. Height ...... 65 mm. Convexity, right valve ...... 28 mm. Convexity, left valve ...... 6 mm. Hinge-line ...... 35 mm.

Locality.— Southwest slope of Mount Jura, Spur 34 at 4250 feet. Zone.—Lilac formation, praecursor zone. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

906 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

PARAPECTEN ACUTIPLICATUS Meek (Plate 25, figures 1-3) Description.— Shell, of medium size, covered with fine, regular con­ centric lamellae; right valve, very highly arched, ornamented with 12 or 13 strong radial ribs which are acute on the umbo but flat-topped on the disk, lirate internally; ears of right valve, smooth but for lamellae in early stages, later ornamented with 4 evenly spaced radial ribs, smooth inter­ nally ; byssal notch, of medium or shallow depth; ctenolium, very weakly developed though traces of it are preserved in the form of spiral volutions on the angle between the right anterior ear and the internal surface of the valve; left valve, flattish, ornamented with 11 or 12 strong, acute radial ribs which are less elevated than those of the right valve, lirate internally; ears of left valve, ornamented with 2 radial ribs, one at, the other near, the cardinal margin, smooth internally except for volutions on the angle as in the right valve. Hinge teeth, long, ridgelike, subparallel to car­ dinal margin, transversely lamellate. Chondrophore, long, narrow, paral­ lel to cardinal margin, supplemented by a central internal resilium pit.

Dimensions.— Of three specimens. Length ...... 65 75 105 mm. Height (cardinal to inferior margin). 57 70 95 mm. Convexity, right valve ...... — 30 45 (?) mm. left valve ...... 7 — — mm. Hinge-line ...... 42 44 55 mm.

The height of the right valve would be notably greater if measured “over all” ; so great being the convexity, that the umbo projects high above the cardinal margin and even overhangs the left valve. Locality.— Holotype is lost and records with it. Probably came from west base of Mount Jura, near Taylorsville. Of the specimens here fig­ ured, the right valve came from midway between Spurs 23 and 24 at 3600 feet, the left valve from Ravine 36 at 4100 feet. Zone.—Hardgrave formation. Synonymy.— Since no specimens comparable with Lima? sinuata Meek, L.f recticostata Meek, or L.? cuneata Meek have been found, there is rea­ sonable doubt of their distinctness from the forms that have been recog­ nized. This doubt is much strengthened by the fact that Meek’s illus­ trations look exactly like distorted specimens of Parapecten acutiplicatus, which are very common. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

DESCRIPTION OF SPECIES 907

Class GASTEROPODA Family TROCHIDAE

Genus TBOCHUS Linnaeus TROCHUS HINCHMANENSIS n. sp. (Plate 26, figure 3)

Description.— Shell, small, regularly turbinate; spire, somewhat high; whorls, subangular, gibbous; suture, deeply impressed; aperture, not seen; base, somewhat flattened. Ornament, of 7 spiral punctate ribs, crossed obliquely by acute radial striae. Ornament of base differs only in being slightly finer. Dimensions.— Apical angle 51° Total length 24 rum.

Locality.—100 yards southeast of Curtice Cliff, Hinchman Ravine. Zone.— Hinchman formation, “coral1” zone. This species is one of several very similar trochids and turbinids which are highly characteristic of the “coral” zone.

Family NERINEIDAE

Genus NERINEA Defrance NERINEA THOMPSONENSIS n. sp. (Plate 26, figures 1 and 2)

Description.— Spire, high; whorls, quadrate, somewhat gradate; suture, concealed by overlapping of whorl; aperture, large, crescentic, thin-lipped; base, steeply conical; anterior canal, long, narrow, attenuate; posterior canal, small; columella, thick; callus, broad, biplicate; spiral lirae, 3 in number, simple, low in position: basal, lateral, and parietal. Ornament, lacking; radial lines, having a pronounced and characteristic sigmoidal curve.

Dimensions.— Apical angle ...... 10° to 11° Height of whorls . 10 mm., 8.5, T.5, 6, 5, 4.5, etc. Diameter of whorls 13 mm., 11, 9, 7.8, 6.5, 5, etc. Total height ...... 77 mm.

Locality.— Coll. J. S. Diller, loc. 2429a, northwest spur of Mount Jura, 4825 feet. Zone.— Thompson formation. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

908 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

Class CEPHALOPODA Subclass AMMONOIDEA Family PHYLLOCERATIDAE Genus PKYLLOCERAS Suess PHYLLOCERAS BURCKHARDTI n. sp. (Plate 26, figures 6 and 7) Description.— Shell, inflated platycone; sides, flattish; venter, roundly arched; umbilicus, very small; lateral ornament, of weak bullae, about 6 or 7 in a quadrant, and regular radial striae which seem to fail toward the umbilicus, but continue to venter; ventral ornament, of striae bend­ ing gently forward across the periphery. Dimensions.— D iam eter...... 67 mm. (restored) Radius ...... 34 min. Radius, 90° back . 28 mm: Umbilical width .. 3 mm. Thickness ...... 19 mm. Thickness, 90° back 12 mm. Comparable species.—Phylloceras cfr. Tcudernatschi von Hauer, Burck­ hardt. Name.—After Dr. Karl Burckhardt. Locality.— Coll. J. S. Diller, loc. 2487, southeast slope of Mount Jura, Spur 41 at about 4,400 feet. Zone.—Hinchman formation, “coral” zone.

Genus HOLCOPHYLLOCERAS Spath HOLCOPHYLLOCERAS FALCIFERUM n. sp. (Plate 26, figures 4 and 5) Description.—Shell, inflated platycone; venter, roundly arched; umbi­ licus, very small; lateral ornament, of varices only, 10 to a whorl at 30 mm. diameter, apparently variable in number, falciform, weakened in mid lateral position and extended forward in a linguiform shape; ventral ornament, of varices, bowed forward, weakened to interruption on peri­ phery. Dimensions.— Diameter ...... 39 mm. (restored) R adius...... 22.5 mm. Radius, 90° back ...... 20 mm. Radius, 270° b a c k ...... 14 mm. Thickness ...... 16 mm: Thickness, 180° back... 11 mm. Thickness, 1 whorl back 8 mm. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

DESCRIPTION OF SPECIES 909

Locality.— Coll. I. C. Russell, loc. 525, 2 miles southeast of Taylorsville. Zone.—Mormon formation, blackwelderi zone.

Family ECHIOCERATIDAE Genus EUECHIOCERAS Trueman & Williams EUECHIOCERAS EXOLETUM n. sp. (Plate 27, figures 1-5) Descriptions—Shell, evolute serpenticone; sides, inflated somewhat in early stages (up to 40 mm.), flattened and convergent in maturity; venter, carinatisulcate; umbilical wall, rounded; lateral ornament, of costae, arising in the umbo and extending on to the venter, stiff and strong in early stages (up to 55 mm.), weak and slightly curved in matu­ rity, 49 to one whorl at 16 mm. diameter, 48 at 30 mm., 43 at 45 mm., 58 at 75 mm.; ventral ornament: costae end on edge of venter with a for­ wardly twisted genicule; carina, strong, obtuse, bordered by medium furrows. Dimensions.— Diameter ...... 48 mm. (100%) Umbilical width 25 mm. (51%) Thickness ...... 11mm. (22.5%) Locality.—Southwest side of Mount Jura, Ravine 33 at 3,750 feet. Zone.—Lilac formation, exoletum zone.

Family ? Genus STIPHROMORPHITES Buckman STIPHROMORPHITES SCHUCHERTI n. sp. (Plate 28, figures 1-3) Description.—Shell, robust serpenticone; sides, flattish, subparallel to slightly convergent, costate; venter, carinate in all stages, fastigate to flat; umbilicus, medium; umbilical wall, smooth, straight, very slightly reclined; shoulder, rounded; lateral ornament: costae arise on umbili­ cal edge, do not extend on to venter, small and close on early whorls, some pairs being connate by their proximal ends, becoming coarser and more distant with age, very slightly flexed; ventral ornament: keel, sharp and prominent on early whorls, gradually weakening from penultimate whorl onwards, weak and rounded at maturity; keel seems to be hollow, that is, septate, only on the penultimate and antepenultimate whorls, and the last few septa are built across a solid keel which is shallowly concave toward the interior; growth lines, angulated strongly forward across the periphery. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

9 1 0 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

Dimensions.— Diameter ...... 113 mm. Diameter, 180° back ...... 78 mm. Diameter, 1 whorl back ...... 56 mm. Diameter, 1% whorl back ...... 36 mm. Radius ...... 68 mm. Radius, 180° back ...... 45 mm. Radius, 1 whorl back ...... 35.5 mm. Umbilical width ...... 35 mm. same, 180° back ...... 23 mm. same, 1 whorl back ...... 15 mm. Thickness ...... 36.5 mm. Thickness, 180° back ...... 22 mm. Thickness, 1 whorl b a c k ...... 17.5 mm. Thickness, 1% whorls b ack ...... 11 mm. ^ Thickness, 2 whorls b ack ...... 7.5 mm. '

Comparable species.— S. nodatipinguis Buckman. Locality.— Southwest side of Mount Jura, Ravine 34 at 4,500 feet. Zone.— Mormon formation, schucherti zone.

Family SONNINIIDAE

Genus PAPILLICERAS Buckman PAPILLICERAS STANTONI n. sp. (Plate 29, figures 1 and 2; Plate 32, figure 1)

Description.—Shell, inflated serpenticone, spinous-mammillate, cari- nate; sides, rounded; venter, rounded, smooth; umbilicus, medium; um­ bilical walls, smooth, rounded, in part overhanging; lateral ornament: costae, coarse, very variable in strength; tubercles, strong, coarse except on penultimate whorl where they are spinous, 1 to every 2 costae on ante­ penultimate whorl, 1 to every 3 on penultimate whorl, 1 to every costa on last whorl; ventral ornament: venter, smooth; keel, weak, obtuse on last whorl, earlier condition, not observed.

Dimensions.— Diameter ...... 123 mm. (restored) Radius ...... 71 mm. Umbilical width ...... 49mm. (restored) same, 180° back ...... 34 mm. (restored) same, 1 whorl back ...... 23 mm. (restored) Thickness, excluding tubercles...... 43 mm. Thickness, 1 whorl back ...... 23 mm. Thickness, 2 whorls b a ck ...... 11 mm. Thickness, 3 whorls b a ck ...... 4 mm. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

DESCRIPTION OP SPECIES, 911

Comparable species.—P. acantherum Buckman. Locality.— Southwest side of Mount Jura, Ravine 34 at 4,600 feet. Zone.—Mormon formation, stcmtoni zone.

PAPILLICERAS BLACKWELDERI n. sp. (Plate 30, figures 1-4)

Description.—Shell, compressed serpenticone, mammillate, carínate; sides, flattish; venter, fastigate; umbilicus, wide; umbilical wall, smooth, reclined; lateral ornament: growth-lines, rather straight, curving forward toward periphery; papillae, on last two whorls at least, earlier ornament, unknown; ventral ornament: venter, smooth but for growth-lines which are anuglated sharply forward across periphery; keel, narrow, high, sharp on pre-ultimate whorls, somewhat less so on last whorl, hollow (that is, septate) at least on penultimate whorl.

Dimensions.— Diameter ...... 225 mm. (restored) Radius ...... 125 mm. (restored) Umbilical width ...... 100 mm. (restored) Height of whorl ...... 67 mm. same, 1 whorl b ack ...... 43 mm. Thickness ...... 30 mm. same, 1 whorl back ...... 15 mm.

Comparable species.—P. micracanthum Buckman. Locality.—Southwest side of Mount Jura, Ravine 34 at 4,670 feet. Zone.—Mormon formation, bbckwelderi zone.

PAPILLICERAS JURAMONTANUM n. sp. (Plate 31)

Description.— Somewhat inflated serpenticone, costate, tuberculate, cari- nate; sides, flattish; venter, roundly arched; umbilicus, medium; umbili­ cal walls, smooth, straight, somewhat reclined; lateral ornament: costae, arise on umbilical edge, extend to venter; x-th whorl: costae, few, distant, spinous; x-lth whorl: costae, strong, more numerous, with few large tubercles; x-2th whorl: costae, weak, very numerous, many connate, no tubercles; x-3th (last) whorl: costae, strong, less numerous (about 36 on the whorl), each surmounted by a papilla about the mid-point, curved toward the periphery; ventral ornament: costae become weak in rising on to the venter, and die Downloaded from gsabulletin.gsapubs.org on November 18, 2014

912 C. H . CRICKMAY---- MOUNT JURA INVESTIGATION

out; growtb-lines are curved forward toward periphery; keel, obtuse in maturity.

Dimensions.— Height ...... 33 mm. Umbilical width ...... 35 mm. same, 180° back ...... 24 mm. same, 1 whorl back ...... 16 mm. same, 1 y2 whorls back ...... 11 mm. Thickness ...... 26 mm. Thickness, 1% whorls back ...... 9 mm.

Remarks.—This form is a homeomorph of species of the much earlier Euhoploceras. Locality.—Southwest side of Mount Jura, Ravine 35 at 4,080 feet. Zone.— Mormon formation, juramontanum zone.

Family SPHAEROCERATIDAE

Genus OTOITES Mascke OTOITES REESIDEI n. sp. (Plate 27, figures 9-11) Description.— Shell, inflated serpenticone, with coronate ornament; sides, distended; venter, gently arched; umbilicus, medium; umbilical wall, rounded, costate; lappets (auricles), not preserved; lateral orna­ ment : costae, strong, obtuse, in last half-whorl, 12 primaries, 29 second­ aries; penultimate half-whorl, 13 primaries, 38 secondaries; tubercles, in mid-lateral zone, 1 to every primary; some secondaries are intercalated, but most are joined to a primary; ventral ornament: secondary costae pass straight and unchanged across periphery.

Dimensions.—■ Including distortion Corrected Diameter ...... 44 mm. Diameter, 180° back ...... 34 mm. Umbilical width ...... 20 mm. 18 mm. same, 180° back ...... 13 mm. Thickness ...... 20 mm. Thickness, 180° b ack ...... 16 mm. Thickness, 1 whorl back ... 12 mm.

Comparable species.—Otoites braikenridgei Sowerby, Itinsaites itinsae McLearn. Locality.—Coll. I. C. Russell, loc. 525, southwest side of Mount Jura Zone.— Mormon formation, blackwelderi zone. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

DESCRIPTION OP SPECIES 913

Genus CHONDROCERAS Mascke CHONDROCERAS RUSSELLI n. sp. (Plate 27, figures 6-8)

Description.— Shell, depressed sphaerocone, passing to subsphaeroconic, costate; sides, inflated; umbilicus, medium compared with other species of the genus; umbilical wall, rounded; lappets (auricles), not preserved; lateral ornament: costae, strong, acute, arising at the umbilical suture, simply bifurcated or separated by secondaries on mid-zone of side; ven­ tral ornament: secondary costae pass straight and unchanged across periphery.

Dimensions.— Paratype: D iam eter...... 39 mm. Diameter, 180° back ...... 30 mm. Diameter, 1 whorl back ...... 23 mm. Umbilical width ...... 13 mm. same, 180° back ...... 6 mm. same, 1 whorl back ...... 5 mm. Thickness ...... 26 mm. Thickness, 180° b ack ...... 22 mm. Thickness, 1 whorl b a c k ...... 20 mm.

Comparable species.—“Sphaeroceras gervillii” auct, Chondroceras delphinus Buckman. Locality.— Southwest side of Mount Jura, Ravine 34 at 4670 feet; para­ type, float from Ravine 34. Zone.-—-Mormon formation, blachwelderi zone. / Family PROPLANULITIDAE

Genus ANAPLANU LITES Buckman ANAPLANULITES HYATTI n. sp. (Plate 32, figure 3; Plate 33)

Description.— Shell, compressed serpenticone, costate; sides, flat; venter, roundly arched; umbilicus, wide; umbilical wall, somewhat rounded, re­ clined ; lateral ornament: costae, obtuse, arising in umbilicus; primaries, die out toward mid-lateral zone, which is therefore weak in ornament; secondaries arise just beyond mid-lateral zone; varices, about 2 to each whorl, not deep or strongly marked; ventral ornament: secondary costae, weak, somewhat prorsiradiate; periphery, not well enough preserved to show character of ribbing on it. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

9 1 4 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

Dimensions.— Diameter ...... 156 mm. (restored) Radius ...... 83 mm. Umbilical width ...... 70 mm. same, 180° back ...... 54 mm. same, 1 whorl b a ck ...... 40 mm. same, 1% whorls b a ck ...... 29 mm. Thickness ...... 36mm. (restored) Comparable species.—Anaplanulites difficilis Buckman. Remarks.—The septal line is considerably more elaborate than that of the genotype. Locality.—Forth ridge of Mount Jura at 5500 feet. Zone.— North Ridge formation.

Family REINECKEIDAE Genus REINECKEITES Buckman REINECKEITES DILLERI n. sp. (Plate 32, figure 2; Plate 34, figures 1-5)

Description.—Shell, serpenticone, costate; sides, flattish; venter, weakly concave; umbilicus, medium; umbilical wall, rounded, semi­ costate; lateral ornament: costae, strong, acute, arcuate, prorsiradiate, simply bifurcated in mid-lateral zone, 16 primaries and 32 secondaries in half-whorl at 60 mm. diam., slightly less numerous on earlier whorls, slightly more on later ones; ribbing becomes slightly coarsened with age; ventral ornament: costae pass squarely on to venter, interrupted on peri­ phery by a narrow, concave smooth band. Dimensions.— Diameter ...... 73mm. (restored) Diameter, 180° back ...... 52mm. (restored) Umbilical width ...... 30 mm. same, 180° back ...... 20 mm. Thickness ...... 18mm. (restored) Thickness, 180° back ...... 14 mm. (restored) Comparable species.—Reineckeites duplex Buckman. Locality.—Upper part of west fork of Hinchman Ravine (Ravine 42) at 4850 feet. Zone.—Forman formation, dilleri zone. Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 23

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014

EXPLANATION OF PLATES 915

E x p l a n a t io n of P l a t e s

P l a t e 23—Jurassic Fossils

F igure 1.—Latomeandra orthogrammica sp. n., clay impression of paratype, twice natural size. F ig u r e 2.—L. orthogrammica sp. n., holotype, twice natural size. The specimen is a natural impression in a volcanic tuff of the upper surface of the coral- lum. It is, therefore, a negative illustration, the reverse of what is shown in Figure 1 ; the edges of the calyces and the septa appear as hollows and grooves; the objects resembling septa are really the fillings of the spaces between septa. Figure 3.—L. orthogrammica sp. n., holotype, twice natural size, diagram of arrangement of septa. Shows two corallites, both being in the same row. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

916 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

Plate 24—Jurassic Fossils

F igure 1.—Pinna expansa Hyatt, lectotype, left lateral view. Figure 2.—Entolium meeki Hyatt, lectotype, left lateral view. F igure 3.—E. meeki Hyatt, cotype, right lateral view. F igure 4.—E. equabile Hyatt, lectotype, left lateral view. F igure 5.—E. equabile Hyatt, cotype, right lateral view, twice natural size. F igure 6.—E. equabile Hyatt, lectotype, twice natural size. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 24

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 25

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014

EXPLANATION OP PLATES 917

P late 25—Jurassic Fossils

Figure 1.—Parapecten acutiplicatus Meek, topotype, an impression in the rock of the flattish left valve. Shows sharp ribbing of the disk in contrast to that of the right valve; also, two radial ribs on the ears. Figure 2.—P. acutiplicatus Meek, topotype, clay cast of impression of ribs of right valve. F igure 3.—P. acutiplicatus Meek, topotype, an impression in the rock of the interior, hinge, and umbo of the right valve. Shows ridge-like hinge-teeth with transverse lamellae. F igure 4.—P. praecursor sp. n., holotype, clay cast of impression in the rock of the right valve. F igure 5.—P. praecursor sp. n., holotype, left valve found in connection with specimen shown in Figure 4. Figure 6.—P. praecursor sp. n., paratype, clay cast of impression of left valve. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

918 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

P l a t e 26— Jurassic Fossils

F ig u r e 1.—Nerinea thompsonensis sp. n., holotype, wax cast of impression in the rock. F ig u r e 2.— N . thompsonensis sp. n., paratype, axial cross-section. Figure 3.—Trochus hinchmanensis sp. n., holotype, clay cast of impression in the rock. F ig u r e 4.—Holcophylloceras falciferum sp. n., holotype, wax cast of impression in the rock, left lateral view. Shows indistinctly the last septum. F igure 5.—H. falciferum sp. n., holotype, dorsal view. F ig u r e 6.— Phylloceras burckhardti sp. n., holotype, left lateral view. F ig u r e 7.—P. burkhardti sp. n., holotype, ventral view. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 26

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 27

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014

EXPLANATION OP PLATES 919

P l a t e 27—Jurassic Fossils

F igure 1.—Euechioceras exoletum sp. n., paratype, right lateral view. Shows young shell. F ig u r e 2.— E . exoletum sp. n., paratype, same specimen as Figure 1, right lateral view. F igure 3.—E. exoletum sp. n., paratype, ventral view. F igure 4.—E. exoletum sp. n., holotype, ventral view. F igube 5.—E. exoletum sp. n., holotype, left lateral view. F ig u b e 6.—Chondroceras russelli sp. n., holotype, left lateral view, clay cast. Figure 7.—Ch. russelli sp. n., paratype, ventro-lateral view, clay cast. F ig u r e 8.—Ch. russelli sp. n., holotype, septal tine. F igure 9.—Otoites reesidei sp. n., holotype, wax cast of impression in the rock, dorcal view. F ig u r e 10.—Otoites reesidei sp. n., holotype, ventral view. F igure 11.—O. reesidei sp. n., holotype, right lateral view.

LX—B o l l . Geo l. Soc. A m., V ol. 44, 1933 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

9 2 0 C. H . CRICK MAY— MOUNT JURA INVESTIGATION

P l a t e 2 8 — Jurassic Fossils

F ig u r e 1.—Stiphromorphites schucherti sp. n., holotype, left lateral view. E’tg u be 2 .—S. schucherti sp. n., holotype, cross-sectional outline. F ig u r e 3.—S . schucherti sp n., holotype, ventral view, slightly oblique. Shows curve of ribbing and growth lines. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

VOL. 44, 1933, PL. 28 BULL. GEOL. SOC. AM.

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 29

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014

EXPLANATION OF PLATES 921

P la te 29—Jurassic Fossils

F ig u r e 1.—Papilliceras stantoni sp. n., holotype, septal lines preserved as thin lamellae on the interior of natural mold of the shell. The illustration was prepared from two photographs and sketched outlines of a third. Con­ trasts have been heightened by use of black and white paint on the specimen. Since the picture is taken from the interior of the shell, the septa shown are really from the left-hand side instead of the right as the reversed picture makes them appear. Shows the great papillae in the form of dark wells on the zone of the first lateral saddle. One shows very plainly in the white space in the centre of the illustration. F igure 2.—P. stantoni sp. n., holotype, right lateral view, a gelatin cast of an impression in the rock. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

922 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

Plate 30—Jurassic Fossils

Figure 1.—Papilliceras blackwelderi sp. n., holotype, right lateral view of a part of the last whorl. F igure 2.—P. blackwelderi sp. n., holotype, ventral view of a small part of the last whorl. F igure 3.—P. blackwelderi sp. n., holotype, cross-sectional outline of half of last two whorls. F igure 4.—P. blackwelderi sp. n., holotype, left lateral view of penultimate whorl. Outlines septal edges marked by contact between black and white paint. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 30

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC, AM. VOL. 44, 1933, PL. 31

JURASSIC FOSSIL Downloaded from gsabulletin.gsapubs.org on November 18, 2014

EXPLANATION OF PLATES 923

Plate 31—Jurassio Fossil Papilliceras juramontanum sp. n., holotype, right lateral view. Shows also a ventral view of a dislocated part of the shell. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

924 C. H . CRICKMAY----MOUNT JURA INVESTIGATION

P l a t e 32—Jurassic Fossils

F ig u r e 1.—Papilliceras stantoni sp. n., holotype, cross-sectional outlines. The dashed outlines are restored. F ig u r e 2.-—Reineckeites dilleri sp. n., paratype no. 1, ventral view. Shows peri­ pheral interruption of ribs. B’ig u b e 3.—Anaplanulites hyatti sp. n., holotype, right lateral view of a small part of last whorl. Shows, though not very well preserved, septal line from first lateral lobe to line of involution. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 32

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014 Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 33

JURASSIC FOSSIL Downloaded from gsabulletin.gsapubs.org on November 18, 2014

EXPLANATION OP PLATES 925

P l a t e 33—Jurassic Fossil Anaplanulites hyatti sp. n., holotype, right lateral view, a plaster cast of Im­ pression in the rock. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

926 C. H. CRICKMAY— -MOUNT JURA INVESTIGATION

P l a t e 34—Jurassic Fossils

F ig u r e 1.—Reineckeites dilleri sp. n., paratype no. 2, right lateral view, a dis­ torted specimen. F ig u r e 2.—R. dilleri sp. n., paratype no. 3, ventral view. Shows peripheral smooth band. F ig u r e 3.—R. dilleri sp. n., paratype no. 1, right lateral view, fragment of a larger specimen. See also Plate 10, Figure 2. F ig u r e 4.—R. dilleri sp. n., holotype, right lateral view. The periphery is lost. Shows first and second lateral lobes and dependent auxiliaries of the septal line. F ig u r e 5.—R. dilleri sp. n., paratype no. 3, left lateral view. The curve of the ribbing is somewhat distorted. Downloaded from gsabulletin.gsapubs.org on November 18, 2014

BULL. GEOL. SOC. AM. VOL. 44, 1933, PL. 34

JURASSIC FOSSILS Downloaded from gsabulletin.gsapubs.org on November 18, 2014