BL1 microsite, Lima Peaks (Cretaceous to of the United States)

Where: Beaverhead County, Montana (44.5° N, 112.6° W: paleocoordinates 44.8° N, 71.0° W)

• coordinate based on nearby landmark

• small collection-level geographic resolution

When: Flood Member (Blackleaf Formation), Late/Upper Albian to Late/Upper Albian (105.3 - 93.9 Ma)

• The BL1 locality occurs 102m above the Kootenai– Blackleaf contact, a stratigraphic position within the Flood Member within this outcrop region.

•Fossils are in unit 59.

• bed-level stratigraphic resolution

Environment/lithology: fluvial-deltaic; fine, green, sandy siltstone

• low-energy fluvial–deltaic and estuarine
• 0.6m thick unit consists of a green, sandy siltstone with approximately 5% of its composition represented by fossils. More detailed compositional analysis shows that the fossil-bearing bed contains approximately 7% very fine sand size grey quartz grains, 3% fine sand size grey quartz grains, 4% fine sand size black or orange chert grains and 1% very fine sand size biotite flakes. The remaining 80% (approximately) is represented predominantly by silt with little clay. Very fine and fine sand size quartz grains are subrounded to subangular in form, whereas all fine-size chert grains are well rounded. The fossil-bearing bed is horizontally discontinuous and roughly lenticular. The calcite-cemented unit fines upwards to become increasingly silt dominated with fewer fossils and exhibits a pervasive (stratigraphy parallel) platy weathering texture. The bed also contains a few smooth, reddish coloured, undulating, locally small surfaces. These likely represent postlithification slickensides coloured red by iron concentration and oxidation (Aschoff and Schmitt 2004). Fossils are permineralised with calcite and dark brown in colour. Both teeth and bone range from less than 1 to 20mm in size.

Size classes: macrofossils, mesofossils

Collected in 2005 and 2006

Primary reference: P. V. Ullmann, D. Varricchio, and M. J. Knell. 2012. Taphonomy and taxonomy of a vertebrate microsite in the mid-Cretaceous (Albian–Cenomanian) Blackleaf Formation, southwest Montana. Historical Biology 24(3):311-328 [P. Mannion/P. Mannion]more details

Purpose of describing collection: general faunal/floral analysis

PaleoDB collection 137590: authorized by Philip Mannion, entered by Philip Mannion on 18.12.2012

Creative Commons license: CC BY (attribution)

Taxonomic list

 Neopterygii -
Neopterygii " sp. 1 " Regan 1923
MOR 1631-212 to -284 (teeth)
Neopterygii " sp. 2 " Regan 1923
MOR 1631-285 to -293 (teeth)
 Testudines -
Testudines indet. Batsch 1788 turtle
MOR 1631-197 to -206 (shell fragments); distinguishable from both Glyptops and the chelydrid
 Testudines - Pleurosternidae
Glyptops sp. Marsh 1890 turtle
MOR 1631-119 to -196 (shell fragments)
 Testudines - Panchelydridae
Chelydridae indet. turtle
MOR 1631-207 to -211 (shell fragments)
 Avetheropoda - Tyrannosauridae
Tyrannosauridae indet. Osborn 1906 tyrannosaurid
MOR 1631-008 (tooth)
 Avetheropoda - Dromaeosauridae
Dromaeosauridae indet. Colbert and Russell 1969 coelurosaur
MOR 1631-001 to -007 (teeth)
 Ornithischia - Ankylosauridae
Ankylosauridae indet. Brown 1908 ornithischian
MOR 1631-025 (teeth)
 Neornithischia - Hadrosauridae
Hadrosauridae indet. Cope 1869 hadrosaurid
MOR 1631-009 to -021 (teeth)
 Neornithischia - Hypsilophodontidae
Hypsilophodontidae indet. Dollo 1882 hypsilophodontid
MOR 1631-022 and -023 (teeth)
 Loricata - Goniopholididae
"Goniopholidae indet." = Goniopholididae
"Goniopholidae indet." = Goniopholididae Cope 1875 crocodilian
MOR 1631-028 to -097 (teeth)
 Loricata -
Bernissartia sp. Dollo 1883 crocodilian
MOR 1631-098 to -118 (teeth)