{{Short description|Geologic formation in Alberta, Canada}} {{Infobox rockunit | name = Foremost Formation | image = Foremost Fm 1.jpg | caption = Outcrops of the Foremost Formation (basal sandstone and MacKay coal zone) along the Milk River at Writing-On-Stone Provincial Park | type = Geological formation | age = Campanian, {{fossilrange|78.5|77.5}} | period = Campanian | prilithology = Sandstone, siltstone, mudstone | otherlithology = Shale, coal | namedfor = Foremost, Alberta<ref name="Glass" /> | namedby = D.B. Dowling, 1915<ref name=Dowling>Dowling, D.B. 1915. Southern Alberta. Geological Survey of Canada, Summary Report 1914, Part L, p. 43-51.</ref> | region = {{Flag|Alberta}} | country = {{Flag|Canada}} | coordinates = | unitof = Belly River Group (Judith River Group) | subunits = | underlies = Oldman Formation | overlies = Pakowki Formation | thickness = up to {{convert|170|m|ft|-1}} | extent = | area = | map = | map_caption = }}
The '''Foremost Formation''' is a stratigraphic unit of Late Cretaceous (Campanian) age that underlies much of southern Alberta, Canada. It was named for outcrops in Chin Coulee near the town of Foremost<ref name="Glass">Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary; 1423 p. on CD. {{ISBN|0-920230-23-7}}.</ref> and is known primarily for its dinosaur remains and other fossils.<ref name="cretaceousdistribution">Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, North America)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press, pp. 574-588. {{ISBN|0-520-24209-2}}.</ref>
== Geology == [[File:Foremost Fm 2.jpg|thumb|left|The basal sandstone of the Foremost Formation beside the Milk River at Writing-On-Stone Provincial Park]] The Foremost Formation is the basal unit of the Belly River Group (called the Judith River Group in the United States). It gradationally overlies the marine shales of the Pakowki Formation. It consists of sediments that were eroded from the mountains to the west and carried northeastward by river systems, where they gradually prograded into the Western Interior Seaway.<ref name=Eberth2005>Eberth, D.A. 2005. The geology. In: Currie, P.J. and Koppelhus, E.B. (eds), Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press, Bloomington and Indianapolis, p. 54-82. {{ISBN|0-253-34595-2}}.</ref>
The bottom of the formation typically consists of a basal sandstone unit overlain by the interbedded coal seams, carbonaceous shales and mudstones of the Mackay coal zone. The center portion consists of interbedded sandstones, siltstones and mudstones, with minor carbonaceous shales. At the top are the interbedded coal seams, carbonaceous shales and mudstones of the Taber coal zone.<ref name="Glass" /><ref name="Eberth2005" /> The basal sandstones, which are commonly referred to as the Basal Belly River Sand, are a significant hydrocarbon reservoir in some parts of Alberta.<ref>{{Cite web|url=http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch24/ch_24.html|title=The Geological Atlas of the Western Canada Sedimentary Basin, Chapter 24: Upper Cretaceous and Tertiary strata of the Western Canada Sedimentary Basin|author=Mossop, G.D. and Shetsen, I., (compilers), Canadian Society of Petroleum Geologists|year=1994|access-date=2013-08-01|url-status=dead|archive-url=https://web.archive.org/web/20130721174353/http://www.ags.gov.ab.ca/publications/wcsb_atlas/a_ch24/ch_24.html|archive-date=2013-07-21}}</ref>
The Foremost Formation outcrops along the Milk, Oldman and Bow Rivers. It is about {{convert|168|m|ft|-1}} thick near Lethbridge,<ref name="Glass" /> {{convert|107|m|ft|-1}} thick near Medicine Hat,<ref name="Glass" /> and {{convert|170|m|ft|-1}} thick at Dinosaur Provincial Park.<ref name=Eberth2005 />
==Paleobiota==
===Invertebrates=== A variety of insects preserved in amber such as the ants ''Haidoterminus'' and ''Boltonimecia'' have been recovered from the Foremost Formation at a site near Grassy Lake, Alberta.<ref name="McKellar2013">{{cite journal |last1=McKellar |first1=R. C. |last2=Glasier |first2=J. R. N. |last3=Engel |first3=M. S. |year=2013 |title=A new trap-jawed ant (Hymenoptera: Formicidae: Haidomyrmecini) from Canadian Late Cretaceous amber |journal=Canadian Entomologist |volume=145 |issue=4 |pages=454–465 |doi=10.4039/tce.2013.23|hdl=1808/14425 |s2cid=53993056 |url=https://kuscholarworks.ku.edu/bitstream/1808/16464/1/Engel_CE_145%284%29454.pdf |hdl-access=free }}</ref><ref name="Borysenko2017">{{Cite journal|last1=Borysenko |first1=L.H. |year=2017 |title=Description of a new genus of primitive ants from Canadian amber, with the study of relationships between stem- and crown-group ants (Hymenoptera: Formicidae) |journal=Insecta Mundi |volume=570 |pages=1–57 |url=http://journals.fcla.edu/mundi/article/view/104678 }}</ref> The formation also includes a variety of freshwater, brackish water and marine molluscs such as ''Ostrea'' and ''Corbula''.<ref name="Glass" />
===Dinosaurs=== The Foremost Formation has produced a lower diversity of documented dinosaurs than other Late Cretaceous units in the region unlike the Dinosaur Park Formation, Horseshoe Canyon Formation, and Scollard Formation.<ref name="alberta-intro-279-281" /> This is primarily due to their lower total fossil quantity and neglect from collectors who are hindered by the isolation and scarcity of well-exposed outcrops.<ref name="alberta-intro-281" /> The fossils are primarily isolated teeth recovered from vertebrate microfossil sites.<ref>" The vertebrate record of the Foremost Formation is best represented by vertebrate microfossil localities. " ([http://www.digitaldreammachine.com/sadrg/formation_foremost.html Southern Alberta Dinosaur Research Group: Foremost Formation] {{Webarchive|url=https://web.archive.org/web/20150923214702/http://www.digitaldreammachine.com/sadrg/formation_foremost.html |date=2015-09-23 }}).</ref>
{{paleobiota-key-compact}} {| class="wikitable" align="center" width="100%" |- ! colspan="7" align="center" |'''Dinosaurs reported from the Foremost Formation''' |- ! Genus ! Species ! Location ! Stratigraphic position ! Material ! Description ! Images |- | ''Colepiocephale'' | ''C. lambei'' | | | | | rowspan="100" | [[File:Colepiocephale updating version.JPG|thumb|center|150px|''Colepiocephale'']] [[File:Dromaeosaurus Restoration.png|thumb|center|150px|''Dromaeosaurus'']] [[File:Hesperornis BW (white background).jpg|thumb|center|150px|''Hesperornis'']] [[File:Probrachylophosaurus_bergei.png|thumb|center|150px|''Probrachylophosaurus'']] [[File:Ojo_Alamo_cf._Richardoestesia_sp_profile_reconstruction.jpg|thumb|center|150px|''Richardoestesia'']] [[File:Saurornitholestes digging Burrows wahweap.jpg|thumb|center|150px|''Saurornitholestes'']] [[File:Stegoceras validum.jpg|thumb|center|150px|''Stegoceras'']] [[File:Thanatotheristes.jpg|thumb|center|150px|''Thanatotheristes'']] [[File:Xenoceratops NT small.jpg|thumb|center|150px|''Xenoceratops'']] |- | ''Dromaeosaurus''<ref name="cretaceousdistribution" /> | Indeterminate<ref name="cretaceousdistribution" /> | | | | |- | ''Hesperornis''<ref name="cretaceousdistribution" /> | <small>''H. regalis''</small><ref>Listed as "''Hesperornis'' cf. ''regalis'' in Weishampel et al."</ref> | | | | |- | ''Paronychodon''<ref name="cretaceousdistribution" /> | Indeterminate<ref name="cretaceousdistribution" /> | | | | |- | ''Richardoestesia''<ref name="cretaceousdistribution" /> | Indeterminate<ref name="cretaceousdistribution" /> | | | | |- | ''Saurornitholestes''<ref name="cretaceousdistribution" /> | Indeterminate<ref name="cretaceousdistribution" /> | | | | |- | ''Stegoceras''<ref name="cretaceousdistribution" /> | Indeterminate<ref name="cretaceousdistribution" /> | | | | |- | ''Thanatotheristes'' | ''T. degrootorum'' | | |right maxilla, right jugal, right postorbital, right surangular, right quadrate, right laterosphenoid, left frontal, and both dentaries | A tyrannosaurid closely related to ''Daspletosaurus'' |- | ''Xenoceratops'' | ''X. foremostensis'' | | |Skull Fragments | |- |''Probrachylophosaurus''<ref>{{Cite journal|last1=Thompson|first1=Mira G. W.|last2=Bedek|first2=Fern V.|last3=Schröder-Adams|first3=Claudia|last4=Evans|first4=David C.|last5=Ryan|first5=Michael J.|date=2021-08-09|title=The oldest occurrence of brachylophosaurin hadrosaurids in Canada|url=https://cdnsciencepub.com/doi/abs/10.1139/cjes-2020-0007|journal=Canadian Journal of Earth Sciences|volume=58 |issue=10 |pages=993–1004 |language=en|doi=10.1139/cjes-2020-0007|bibcode=2021CaJES..58..993T |s2cid=238720084 |url-access=subscription}}</ref> |indeterminate | | | | |- |}
== See also == {{Portal|Earth sciences|Paleontology|Dinosaurs||}} * List of dinosaur-bearing rock formations
==Footnotes== {{Reflist|refs= <ref name="alberta-intro-279-281">"Introduction," Ryan and Russel (2001); pages 279-281.</ref> <ref name="alberta-intro-281">"Introduction," Ryan and Russel (2001); page 281.</ref> }}
==References== *{{cite book |last1=Ryan |first1=M. J. |last2=Russell |first2=A. P. |year=2001 |chapter=Dinosaurs of Alberta (exclusive of Aves) |title=Mesozoic Vertebrate Life |editor-last=Tanke |editor-first=D. H. |editor2-last=Carpenter |editor2-first=K. |publisher=Indiana University Press |pages=[https://archive.org/details/mesozoicvertebra0000unse/page/279 279–297] |isbn=0253339073 |chapter-url=https://archive.org/details/mesozoicvertebra0000unse/page/279 }}
{{coord missing|Alberta}}
{{Western Canadian Sedimentary Basin| South AB=yes}}
Category:Western Canadian Sedimentary Basin Category:Cretaceous Alberta Category:Campanian Stage Category:Upper Cretaceous Series of North America