Buelna Fm., Cerro Rajon, Caborca Region, Mexico - Stewart et. al 1984: Dyeran, Mexico

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
Hormogoneae - Oscillatoriales - Girvanellaceae
Girvanella mexicana Cooper et al. 1952
unclassified
Olenllus truemani
Salterellidae
Salterella sp. Billings 1861
Salterella cf. pulchella Billings 1861
Salterella maccullochi (Murchison 1859)
Archaeocyatha - Archaeocyathida - Archaeopharetridae
Protopharetra sp. Bornemann 1884
Archaeocyatha - Capsulocyathida - Coscinocyathidae
Coscinocyathus sp. Bornemann 1884
Tergomya - Scenellidae
Scenella cf. reticulata Billings 1872
Paterinata - Paterinida - Paterinidae
Paterina sp. Beecher 1891
Hyolithida - Hyolithidae
Hyolithes whitei Resser 1938
recombined as Nevadotheca whitei
Hyolithes sp. d'Eichwald 1840
Orthothecida - Orthothecidae
Orthotheca buelna Lochman 1952
Trilobita - Redlichiida
Olenelloidea indet. Walcott 1890
Trilobita - Redlichiida - Olenellidae
Olenellus puertoblancoensis (Lochman 1952)
recombined as Olenellus (Paedeumias) puertoblancoensis
Olenellus fremonti Walcott 1910
recombined as Mesonacis fremonti
Trilobita - Redlichiida - Wanneriidae
Wanneria sp. Walcott 1910
Wanneria walcottana (Wanner 1901)
Trilobita - Corynexochida - Dorypygidae
Bonnia sonora Lochman 1952
Trilobita - Antagmidae
Onchocephalus mexicanus Lochman 1952
Onchocephalus buelnaensis Lochman 1952
Sombrerella mexicana Lochman 1948
Antagmus solitarius Lochman 1952
Antagmus buttsi (Resser 1939)
unclassified
Cruziana sp. d'Orbigny 1842
trace fossil
Palaeophycus sp. Hall 1847
trace fossil
see common names

Geography
Country:Mexico
Coordinates: 30.4° North, 111.9° West (view map)
Paleocoordinates:4.3° South, 102.8° West
Time
Period:Cambrian Epoch:Early/Lower Cambrian
10 m.y. bin:Cambrian 2
*Period:Early/Lower Cambrian *Epoch:Caerfai
*International age/stage:Late/Upper Lenian *Local age/stage:Late/Upper Dyeran
Key time interval:Dyeran
Age range of interval:516.00000 - 513.00000 m.y. ago
* legacy (obsolete) database fields
Stratigraphy
Geological group:Bonnia-Olenellus Formation:Buelna
Stratigraphic resolution:group of beds
Stratigraphy comments: All lithology/stratigraphic details are based primarily on exposures of rocks in the Cerro Rajon area. Unit is 77.5m thick. Formation creates a conspicuous ridge or ledge in most areas. The broad facies included in the formation and a lack of information regarding the lithology containing the fossils prevents a single paleoenvironment from being selected.
Lithology and environment
Primary lithology:gray,green,yellow lithified siltstone
Secondary lithology:"cross stratification",planar lamination,brown,yellow lithified sandstone
Lithology description: Mixed rock types. Siltstone, greenish gray to yellowish gray, coarse silt. Quartzite, yellowish brown, fine to medium grained, laminated and cross stratified. Limestone and dolomite, sandy in parts, light-gray, commonly weathering moderate brown, laminated and cross stratified.
Geology comments: Represents a southern extension of the Cordilleran miogeocline, rocks may be offset 700 to 800km along a left- lateral fault.
Taphonomy
Modes of preservation:trace,original calcite
Size of fossils:macrofossils,mesofossils
Collection methods and comments
Collection methods:bulk,field collection
Reason for describing collection:biostratigraphic analysis
Metadata
Database number:10684
Authorizer:M. Patzkowsky Enterer:P. Borkow
Modifier:J. Alroy Research group:marine invertebrate
Created:2001-06-11 12:13:21 Last modified:2003-07-10 19:51:10
Access level:the public Released:2001-06-11 12:13:21
Creative Commons license:CC BY
Reference information

Primary reference:

3951. J. Stewart, M. A. S. McMenamin, and J. M. Morales-Ramirez. 1984. Upper Proterozoic and Cambrian rocks in the Caborca Region, Sonora, Mexico - physical stratigraphy, biostratigraphy, paleocurrent studies, and regional relations. U. S. Geological Survey Professional Papers (1309)1-33 [M. Patzkowsky/P. Borkow]