232 STEPHEN P. ALPERT CAMBRIAN TRACE FOSSILS 22 7 the width decreases slightly toward one end 10 to 25 mm wide, possessing sharp, oblique, (presumably the posterior), as in Rusophycus, 0.5 to 1 mm wide scratchmarks. The distance and because the markings do not form a long between the paired mounds (PI. 2, fig. 7, right) trackway as in Diplichnites. is 12 mm; the overall width is 48 mm. This These shallow traces probably were formed fossil is somewhat similar to the Upper Or- by a swimming trilobite that alighted or set dovician Rusophycus sp. of Bender (1963, pi. down to rest on the substrate, without burrow- 12, fig. 3), placed in Cruziana petraca by Seil- ing, and left the impressions or shallow scratch- acher (1970). The fossil also resembles a marks of its appendages. Four parallel, oblique resting form of Cruziana barbata Seilacher scratchmarks, crosscutting the transverse mark- (1970, text-fig. la). Other trilobite markings ings on one specimen (PI. 2, fig. 10) may rep- (Monomorphichnus) occur on the same slab. resent the activity of the trilobite in leaving A final form of Rusophycus present in the its resting place. It is possible that, had the White-Inyo Mountains is described below as a trilobite burrowed deeper, a form similar to new species. R. cf. R. dispar (present in same beds) would have been produced. RUSOPHYCUS RADWANSKII n. sp. Similar, but smaller, shallow trilobite mark- PI. 3, fig. 7 ings occur in quartzite of the upper Andrews "Cruziana rusofomus" ORLOWSKI, RADWANSKI, & Mountain Member of the Campito Formation RONIEWICZ, 1970 (partim), p. 350, 356, PL 1, (PI. 3, fig. 3; only specimens collected). The fig. c (invalid conditional name). specimens are 15 to 20 mm wide and long, and Holotype.—UCLA 49585, Plate 3, figure 7; consist of two separated rows (5 mm apart) collected by J. E. Morhardt, Bishop, California. of fine oblique scratchmarks. Very similar Description.—Large, bilobed, relatively deep specimens from Finnmark are described by resting burrows, with fine bidirectional scratch- Banks (1973, p. 4, text-fig. 4B) as "proto- marks. Overall shape elliptical to circular. The Rusophycus." holotype (PL 3, fig. 7) is 55 mm wide, 100 A specimen (PI. 1, fig. 8) similar to Ruso- mm long, and 6 mm deep. One other specimen phycus sp. of Young (1972, p. 15, text-figs. was collected (same locality) ; it is 55 mm wide, 4a,b) from the basal Cambrian of western Can- 45 mm long, and 9 mm deep. The specimen ada was found in quartzitic siltstone of the of Orlowski et al. (1970, pi. 1, fig. c) is about basal Harkless Formation. It is 23 mm long, 60 mm wide and 100 mm long. 13 mm wide, 3 mm deep, and has a few in- The center of the cast is roughly circular, distinct 1.5 mm wide transverse ridges. The with a faint median groove; the central area median groove of the bilobed cast is deepest is surrounded by fine concentric scratchmarks. and widest in the center. The specimen lacks The median groove is wider and deeper in the the longitudinal markings present on Young's posterior region than in the anterior region specimen. of the cast. An unusual form of Rusophycus (PI. 2, fig. 7) was collected in quartzite of the lower Diagnosis.—R. radzvanskii differs from the Harkless Formation. The trace consists of numerous other species of Rusophycus in that circular to elliptical, paired, separated mounds, it possesses bidirectional scratchmarks arranged EXPLANATION OF PLATE 2 FIGS. 1-3,5—Rusophycus cf. R. dispar Linnarsson. Hypotypes. 1, UCLA 49602, Harkless Formation, Loc. 6049, specimen uncoated, X0.75; 2, UCLA 49603, Harkless Formation, Loc. 6049, Xl; 3, UCLA 49604, upper Wood Canyon Formation, Echo Mountain, Chloride Cliffs Quadrangle, Death Valley, collected by B. W. Troxel, X0.75; 5, UCLA 49605, upper member, Deep Spring Formation, Loc. 6154, X0.75. 4—Rusophycus sp. Hypotype, UCLA 45728, upper member, Deep Spring Formation, Loc. 6158, collected by C. A. Nelson, XL 6—Rusophycus sp. Hypotype, UCLA 49606, Andrews Mountain Member, Campito Formation, Loc. 6103, X 1.5. 7—Rusophycus sp. Hypotype, UCLA 49607 (at right). Harkless Formation, Loc. 6051, X0.9. 8—Rusophycus sp. Hypotype, UCLA 49608, Andrews Mountain Member, Campito Formation, Loc. 6103, xl. 9,10—Rusophycus sp., upper member, Deep Spring Formation, Loc. 6158. Specimens collected by C. A. Nelson. Hypotypes. 9, UCLA 49609, upper bedding surface, Xl; 10, UCLA 45727, lower bedding surface, Xl. 234 STEPHEN P. ALPERT almost concentrically around the deep central specimen occurs in a thin shale layer on quart- part of the cast, where the median groove is zitic siltstone, upper Andrews Mountain Mem- very faint. ber, Campito Formation. Stratigraphic distribution.—The specimen of A third type of Diplichnites (PI. 1, fig. 13) Orlowski et al. (1970) occurs in the Lower occurs in quartzitic sandstone of the upper An- Cambrian Holmia horizon of Poland. The two drews Mountain Member, Campito Formation White-Inyo Mountains specimens occur in the (three specimens collected). The trackway is lower part of the Fallotaspis Zone, in quart- straight to curved, and consists of two separated zitic siltstone of the upper Andrews Mountain rows of blunt scratchmarks, preserved as hy- Member of the Campito Formation. pichnial ridges. Within each row, the ridges are transverse to featherstitch in arrangement. Genus DIPLICHNITES Dawson, 1873 A faint, outer, hypichnial groove, 2 mm wide, parallels one side of the trackway on some Diplichnites DAWSON, 1873, p. 19-20; MILLER, 1889, p. 554; SEILACHER, 1955, p. 343; HANTZSCHEL, specimens. The two rows are 5 to 6 mm apart; 1962, p. W191-W192; RADWANSKI & RONIEWICZ, the overall width is 20 to 25 mm. 1963, p. 269; HANTZSCHEL, 1965, p. 32; GLAES- SNER, 1969, p. 383; CRIMES, 1970a, p. 56-57; CRIMES, 1970b, p. 119-124; YOUNG, 1972, p. 13; Genus MONOMORPHICHNUS Crimes, 1970 HANTZSCHEL, 1975, p. W61; OSGOOD & DKENNEN, Type species.—Monomorphichnus bilineatus 1975, p. 323-324. Acripes MATTHEW, 1910, p. 122; HANTZSCHEL, 1965, Crimes, 1970a, p. 57-58, plate 12, figure c. p. 6. Diagnosis.—Parallel scratchmarks made by the appendages of one side of a trilobite in Type spccics.—Diplichnites acnigma Dawson, motion sideways. 1973, p. 19-20, text-figure 3. Description.—Biserial walking trackway, con- MONOMORPHICHNUS MULTILINEATUS n. sp. sisting of two separated, parallel rows of trans- PI. 1, figs. 1,2 verse to oblique linear markings, pits, or scratchmarks and pits. Hypichnial cast of Type specimens.—Holotype: UCLA 49590, trackway consists of ridges and mounds. Plate 1, figure 1. ITypotype: UCLA 49591, Remarks.—Dawson (1873) first interpreted Plate 1, figure 2. Diplichnites as the trace of a fish walking on Description.—Five or six parallel, straight to pectoral or ventral fin spines, and later (1894, slightly curved scratchmarks. The central p. 264) as probable amphibian tracks. Diplich- scratchmarks are deeper and wider (up to 1 nites is now regarded as walking tracks of mm wide) than those to either side. In the trilobites (Crimes, 1970b) and possibly other holotype (PI. 1, fig. 1), there are two fine arthropods. scratchmarks on one side, and one on the Diplichnites contains two named species: D. other side, of the three deep central claw- acnigma Dawson, 1873, and D. govcnderi Sav- marks. The specimens are 15 to 25 mm long age, 1971; however, several species of other and 6 to 8 mm wide. Lateral repetition was not ichnogenera can be transferred to Diplichnites. observed. Diplichnites in the White-Inyo Mountains.— Diagnosis.—M. multilineatus differs from M. Diplichnites is rare in the White-Inyo Moun- bilineatus in having scratchmarks in sets of 5 tains ; it occurs in the Deep Spring, Campito, or 6, with the central marks deeper than the and Harkless Formations. outer marks. One form consists of two separated rows Stratigraphic distribution.—M. multilineatus of transverse scratchmarks (PI. 1, fig. 7). Small occurs in quartzite of the upper member of outer pits or scratchmarks may also be pres- the Deep Spring Formation (one specimen, PI. ent. The two rows are about 5 mm apart; the 1, fig. 2), and in quartzite of the lower Plark- overall width is 20 to 25 mm. Two specimens less Formation (PI. 1, fig. 1, plus a few other were found, one in siltstone of the upper mem- possible specimens, such as on PI. 2, fig. 7, ber of the Deep Spring Formation, the other upper left of center). in shale of the basal Harkless Formation. Another specimen of Diplichnites (PI. 1, fig. "Trilobite Claw Scratchmarks" PI. 3, figs. 1,2 3) has two narrow, irregular, separated rows of sharp transverse scratchmarks. The mark- Description.—Small, shallow, individual claw ings in each row are closely spaced and no pat- scratchmarks, on upper bedding surfaces. The tern is discernible. The two rows are 6 mm scratchmarks are 5 to 10 mm long, 1 to 2 mm apart; the overall width is 15 to 18 mm. The wide, and straight to slightly curved. Most CAMBRIAN TRACE FOSSILS 22 7 of the scratchmarks were made by appendages ridges, about 1 mm wide. The ridges are with two claws. The displaced sediment may straight to slightly undulatory, 1 to 2 mm apart be preserved as lateral ridges, or as a mound near the center, and about 3 to 5 mm apart in at the end of the scratchmark. the outer region. The ridges are about 40 to Remarks.—The markings may be isolated 60 mm long; the overall diameter of the fossil or in clusters, and probably were made by is about 100 to 120 mm. There are about 15 swimming trilobites that occasionally scratched radiating ridges in a 90° quadrant.