. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Mississippian Blastoids from Montana • Sprinkle and Gutschick 103 limestone surface exposed in place in a small saddle near the Baldy Mountain Sec- tion (BY) (Text-Fig. 4) in the southern Bridgers, along with a single specimen of Orophocrinus sp. This bed appears to be near the top of the Lodgepole (probably in the upper 200 ft or 61 m), but its exact position could not be determined. A single specimen of Phaenoschisma? sp. was found in the float on the north flank of Saddle Peak in the southern Bridgers; it also ap-
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. Mississippian Blastoids from Montana • Sprinkle and Gutschick 103 limestone surface exposed in place in a small saddle near the Baldy Mountain Sec- tion (BY) (Text-Fig. 4) in the southern Bridgers, along with a single specimen of Orophocrinus sp. This bed appears to be near the top of the Lodgepole (probably in the upper 200 ft or 61 m), but its exact position could not be determined. A single specimen of Phaenoschisma? sp. was found in the float on the north flank of Saddle Peak in the southern Bridgers; it also ap- pears to have come from the upper 200 ft (61 m) of the Lodgepole. The Lodgepole Limestone is about 800 ft (244 m) thick in the southern Bridgers, so that all of the specimens in the upper Lodgepole blastoid fauna probably came from beds between 600 and 800 ft (183-244 m) above the base of the formation (see Text-Fig. 2). Both the middle and upper Lodgepole blastoid faunas are less well known than the abundant and widespread lower Lodgepole blastoid fauna, implying that these younger faunas could be consider- ably more diverse than is presently known. We found no blastoids between 200 and 600 ft (61-183 m) above the base of the formation, although fossiliferous and ap- parently favorable beds are present at sev- eral sections. Additional blastoid genera and localities will probably be found in the upper part of the Lodgepole in western Montana and adjacent areas as more field work is done on these units. OCCURRENCE AND DISTRIBUTION Of the three blastoid faunas now known from the Lodgepole and Allan Mountain Limestones in western Montana, only the lower fauna is sufficiently widespread and abundant to permit an analysis of its dis- tribution pattern. Blastoids in the lower fauna have been collected at 31 of the 57 Lodgepole and Allan Mountain sections in western Montana studied by the authors during 1964-66 (Text-Fig. 1). A dividing line running through western Montana (see Tex
Size: 1806px × 1383px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorharvarduniversity, bookcentury1900, booksubjectzoology
