1 kilometer south of Taylors Falls, half kilometer north of Folsom Island (Cambrian of the United States)

Also known as 82b of Resser 1937

Where: Chisago County, Minnesota (45.4° N, 92.7° W: paleocoordinates 19.2° S, 79.2° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Elvinia trilobite zone, Mill Street Conglomerate Member (Franconia Formation), Steptoean (497.0 - 493.5 Ma)

• member-level stratigraphic resolution

Environment/lithology: coastal; lithified sandstone

• We suggest that the boulders of the conglomerate provided such a protected habitat, at least locally, in a quartz-sand beach habitat. The conical and limpetlike forms could safely move among the boulders, sheltered from any heavy wave action, if such were present. By comparison to present-day rocky marine shores, one may argue that although stromatolites did not develop in this environment, algal films could flourish on the boulders to provide a food supply for the mollusks.
• very coarse-grained, consisting of angular to well rounded basalt blocks as much as 2 feet in diameter surrounded by fine- to medium-grained, buff quartzose sandstone. (Yochelson & Webers 2006)

Size class: macrofossils

Preservation: cast

Collected by C. P. Berkey in 1890-1898; reposited in the AMNH, USNM

Primary reference: C.P. Berkey. 1898. Geology of the St. Croix Dalles, part 3. Paleontology. American Geologist 21:270-294 [P. Wagner/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 156300: authorized by Pete Wagner, entered by Pete Wagner on 16.05.2014

Creative Commons license: CC BY (attribution)

Taxonomic list

• Non-molluscs include:

•Lingula ampla Owen

•Lingula antiqua Hall

•Lingulepis pinniforms Owen (= Lingulepis acuminata Conrad)

•Obolella polita

•Oboldla polit,l Hall.

Show authors, comments, and common names
Trilobita
 Olenida - Pterocephaliidae
Camaraspis convexus3, "Camaraspoides berkeyi" = Camaraspis berkeyi3
"Camaraspoides berkeyi" = Camaraspis berkeyi3 Resser 1935 trilobite
Agraulus convexus var. A
 Asaphida - Dikelocephalidae
Berkeia typica n. gen. n. sp.1
Berkeia typica n. gen. n. sp.1 Resser 1937 trilobite
Agraulus convexus var. B
 Corynexochida - Cheilocephalidae
Cheilocephalus stcroixensis
Paragastropoda
 Mimospirida - Onychochilidae
"Scaevogyra minnesotensis n. sp." = Scaevogyra swezeyi
"Scaevogyra minnesotensis n. sp." = Scaevogyra swezeyi Whitfield 1878
Gastropoda
 Bellerophontida - Tropidodiscidae
"Euomphalus strongi" = Strepsodiscus strongi, "Hypseloconus franconiensis n. sp." = Strepsodiscus franconiensis
"Euomphalus strongi" = Strepsodiscus strongi Whitfield 1878 snail
Euomphalus n. ssp. strongi sinistrorsus
"Hypseloconus franconiensis n. sp." = Strepsodiscus franconiensis Berkey 1898 snail
Tergomya
 Kiringellida - Hypseloconidae
"Hypseloconus stabilis n. sp." = Kirengella stabilis, "Tryblidium rectilaterale n. sp." = Kirengella rectilateralis, "Hypseloconus capuloides n. sp." = Proteroconus capuloides
"Hypseloconus stabilis n. sp." = Kirengella stabilis Berkey 1898
"Tryblidium rectilaterale n. sp." = Kirengella rectilateralis Berkey 1898
"Hypseloconus capuloides n. sp." = Proteroconus capuloides Berkey 1898
 Kiringellida -
Hypseloconus elongatus n. gen. n. sp., Hypseloconus cornutiformis n. sp.
Hypseloconus elongatus n. gen. n. sp. Berkey 1898
Hypseloconus recurvus elongatus
Hypseloconus cornutiformis n. sp. Berkey 1898
 Tryblidiida - Tryblidiidae
"Tryblidium convexum n. sp." = Proplina convexum, "Tryblidium aduncum n. sp." = Proplina cornutaformis, "Tryblidium extensum n. sp." = Proplina extensum, "Tryblidium corpulentum n. sp." = Proplina corpulentum
"Tryblidium convexum n. sp." = Proplina convexum Berkey 1898
"Tryblidium aduncum n. sp." = Proplina cornutaformis Walcott 1879
"Tryblidium extensum n. sp." = Proplina extensum Berkey 1898
"Tryblidium corpulentum n. sp." = Proplina corpulentum Berkey 1898
Lingulata
 Lingulida - Obolidae
"Lingula ampla" = Lingulella ampla2, "Lingula antiqua" = Lingulella (Lingulepis) acuminata2, Lingulepis pinnaformis2, "Obolella polita" = Dicellomus politus2
"Lingula ampla" = Lingulella ampla2 Owen 1852
"Lingula antiqua" = Lingulella (Lingulepis) acuminata2 Conrad 1839
"Obolella polita" = Dicellomus politus2 Hall 1861
1Resser 1937; 2Walcott 1912; 3Yochelson and Webers 2006