Malone Mountains and outlying foothills, Lower Malone Formation (Jurassic of the United States)

Where: Texas (31.2° N, 105.6° W: paleocoordinates 26.3° N, 53.2° W)

• coordinate based on nearby landmark

• local area-level geographic resolution

When: Lower Member (Malone Formation), Kimmeridgian (157.3 - 152.1 Ma)

• "Malone formation... the formation consits of two divisions. The lower division (685 ft) consists of limestones, conglomerates, sandstones, sandy shales, and impure limestones... [Ammonites] establish the Kimmeridgian age of this division."

• member-level stratigraphic resolution

Environment/lithology: deltaic; lithified mixed carbonate-siliciclastic sediments

• Classification based on the following description: "...the lower and upper members of the Malone Formation are raised to formation status and called the Broadtop Hill Formation and Cedar Canyon Formation, respectively, in order to reflect their true lithologic character. The Broadtop Hill Formation consists of clastic, immature sediments and represents deposition within a fan-delta system. Lithologies include conglomerate, calcareous lithic arenite, sandstone, siltstone, shale, and limestone." cited from B. Tickner (2005). Stratigraphic studies and microfacies analysis of the Jurassic succession, Malone Mountains, west Texas.

Size class: macrofossils

Collection methods: collected in the summers of 1934 and 1935

Primary reference: C. C. Albritton. 1937. Faunal diversity in Malone Mountains beds, Texas. Pan-American Geologist 68(4):257-262 [M. Aberhan/S. Nurnberg]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 69010: authorized by Martin Aberhan, entered by Sabine N├╝rnberg on 15.02.2007, edited by Mark Uhen

Creative Commons license: CC BY (attribution)

Taxonomic list

• "The lists of fossils are not complete for any of the three formations. The particular species entered are chosen either because their age has been subject of controversy, or, because they are important in the dating of formations, or, because they are unusually abundant in their respective formations."
 Irregularia - Clypeidae
Pygurus sp. Agassiz 1839 sea urchin
 Holectypoida - Holectypidae
Holectypus crangini n. sp. sea urchin
 Trigoniida - Trigoniidae
 Trigoniida - Myophorelloidae
"Trigonia vyschetzkii" = Stoyanowella vyschetzkii
"Trigonia vyschetzkii" = Stoyanowella vyschetzkii Cragin 1905 clam
 Carditida - Crassatellidae
 Carditida - Astartidae
 Pholadida - Pleuromyidae
 Lucinida - Lucinidae
Lucina potosina clam
L. potosina var. metrica
 Ammonitida - Ataxioceratidae
 Ammonitida - Perisphinctidae
 Ammonitida - Aspidoceratidae