The nonmarine mollusks of the Late Oligocene–Early Miocene Cabbage Patch fauna of western Montana. I. Geologic setting and the family Pupillidae (Pulmonata: Stylommatophora)

Pierce, Harold G.; Rasmussen, Donald L.

doi:10.1017/s0022336000033473

Cited by 12 publications

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“…Six of the terrestrial taxa of Group III, two of Group IIC, and one aquatic taxon are members of the late Oligocene-early Miocene (Arikareean) Cabbage Patch fauna of southwestern Montana (Pierce and Rasmussen, 1992;Pierce, 1992;1993). The proposed climatic preference of the Cabbage Patch fauna was: MAT >10°C, January mean temperature >5°C, July mean temperature 15°-20°C, precipitation >50 cm, and elevation >800 meters (Pierce, 1993:990).…”

Section: Discussionmentioning

confidence: 99%

“…Environment and Distribution.-Hendersonia are "found on well-shaded, leafy, and rather humid slopes, on limestone terranes" and are spottily distributed "in the upper Mississippi Valley east to the Alleghenies in Pennsylvania and North Carolina" (LaRocque, 1970:555-556). Recent Waldemaria live only in Japan, although it is known as fossil from middle Miocene (early Barstovian) Flint Creek beds of southwestern Montana (Pierce and Rasmussen, 1989), where there is a suggestion of a moist, temperate climate.…”

Section: Systematic Paleontologymentioning

confidence: 99%

“…8.F-8.I) Discussion.^ -Except for minor differences such as the body whorl being slightly more rounded than the holotype, which could easily fall within the range of normal specific variation, and the presence of low obscure costae (about six per circumferential millimeter) overprinted on the fine collabral costellae (>20 per f-E: restoration; D. lateral; E. apertural; HELICINIDAE. F-I: Waldemaria monticula Rasmussen, 1989), F-H: Hypotype (CM 41622), X5; F, dorsal; G. umbilical; H. apertural; I: W. monticula, Hypotype (PHCN 117), XIO, partial operculum; J-M; Lucidella columbiana n. sp., J-L: Holotype (CM 41620), X5; J. apical; K. umbilical; L. apertural; M. L. columbiana Paratype (KLfMIP 289705) XIO, apical detail, apex to lip; N-R: Lucidella salishora n.…”

Section: Systematic Paleontologymentioning

confidence: 99%

“…cit.). Pierce investigated the late Oligocene-Miocene Cabbage Patch l.f. of Granite and Powell Counties (Pierce and Rasmussen, 1992;Pierce, 1992Pierce, , 1993, and the small Miocene Flint Creek l.f. of Granite County (Pierce and Rasmussen, 1989). Evanoff briefly mentioned the mollusks of the White River l.f., late Eocene-Oligocene, of the Douglas County, Wyoming area .…”

Section: Introductionmentioning

confidence: 99%

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Late Eocene-Oligocene nonmarine mollusks of the northern Kishenehn Basin, Montana and British Columbia

Pierce¹,

Constenius²

2001

Annals of the Carnegie Museum

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The Kishenehn Basin is a narrow, asymmetric graben, developed during an episode of crustal extension occurring from middle Eocene to early Miocene time . The Flathead listric normal fault system defines the northeast margin of the basin. The southwest margin is either bounded by antithetic normal faults or is onlapped by Kishenehn Basin strata. High rates of basin subsidence and synextensional sedimentation resulted in an immense thickness of middle Eocene-early Miocene strata (stratigraphic thickness, -5000 m) and a relatively uninterupted depositional record. Provenance and paleocurrent studies indicate that the ancestral Livingston, Lewis, and Clark ranges to the east contributed not only vast amounts of detritus to the Basin, but also ample runoff that included seasonal snow-melt. Sediment ages of outcrops within the basin are linearly banded, with the course of the Flathead River exposing late Eocene-early Oligocene sediments (Chadronian-Orellan NALMA's), and with the oldest sediments on the southwest and youngest on the east margins of the basin, respectively. An unnamed tephra at the north end of the basin provides a date of 33.0±1.0 Ma (early Oligocene, Orellan NALMA).The molluscan fauna is extremely diverse, 55 taxa (35 terrestrial, 20 aquatic), of which 32 taxa are new, and seven are revised taxonomically. This fauna is clearly divisible into three Groups. Group I is a relict tropical wet fauna, existing along waterways in the sheltered environment of the basin. It may typify the pre-middle Eocene (early Duchesnean NALMA) tropical climate of the Western Interior of North America. Modern analogs of these taxa are found in the Caribbean, Central and South America. Group II is a semitropical, semiarid fauna that developed after the climatic changes of the middle Eocene. Modern analogs are found in a band from the north coast of the Gulf of Mexico across the southern United States and northern Mexico to Southern and Baja California. Essentially 100% of the Group I and II analog taxa are now extra-limital, displaced to the south. Group III taxa developed in uplands along the east margin of the basin. Modern analogs of these taxa are common in the east-central United States. The coexistence of these climatically disparate groups of mollusks is a reflection of the large paleotopographic relief that existed between the basin floor and the eastern mountain peaks, which rose at least 2,000 meters above the basin floor, and permitted microclimates that varied from arid subtropical in the basin to humid temperate in the uplands. At the older localities. Group III taxa were, probably, transported into the basin by run-off from the mountains, but during the climatic cooling of the latest Eocene-early Oligocene, Groups I and II taxa were replaced by Group III taxa in the low-lands. Group III analog taxa are 87% endemic, although their modern centers of distribution are displaced eastward into an area of greater precipitation.The following taxa are described herein as new:

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Section: Discussionmentioning

confidence: 99%

Section: Systematic Paleontologymentioning

confidence: 99%

Section: Systematic Paleontologymentioning

confidence: 99%