"Ammonite" bed - Ambatolafia, Mahajanga Basin, Madagascar (Cretaceous of Madagascar)

Where: Mahajanga, Madagascar (16.5° S, 46.2° E: paleocoordinates 40.5° S, 29.6° E)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Microfossil Bed Member, Early/Lower Albian (112.0 - 109.0 Ma)

• From Ammonite bed. Ammonites collected from a sandstone layer ("ammonite bed"), which is 15-20 cm thick. Above this unit is a 15 cm thick bed of siltstone ("microfossil bed", with sparse gastropods and bivalves. Overlain by further barren siltstone of 10 cm thickness. The fauna belongs to the Cleoniceras besairiei Zone of the lower Albian (Collignon, 1963).

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified, glauconitic sandstone

• No specific environmental or geologic data reported by authors.
• Hard, glauconite sandstone.

Size class: macrofossils

Reposited in the MfN

Collection methods: bulk, sieve,

• The material is deposited in the Museum für Naturkunde, Berlin, Germany. This is a recollection of a locality originally reported by Collignon (1949), based on collections by H. Besairie and V. Hourcq. This locality fell into oblivion until rediscovered by Fren ch-Madagascar ammonite traders a few years ago, who had relocated the the locality. Samples dried and treated with a saturated Glaubers salt solution, then washed through sieves with mesh sizes of 2, 1, 0.5, 0.2, and 0.064 mm. Gastropods only picked from the 2, 1 and 0.5 mm fractions.

Primary reference: S. Kiel. 2006. New and little-known gastropods from the Albian of the Mahajanga Basin, northwestern Madagascar. Journal of Paleontology 80(3):455-476 [A. Miller/A. Hendy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 60071: authorized by Austin Hendy, entered by Austin Hendy on 29.04.2006

Creative Commons license: CC BY (attribution)

Taxonomic list

• Exhaustive for gastropoda. Bivalves and ammonites are excluded from this publication. These are presumably listed by Collignon (1949).
Gastropoda
  -
Mahajangina weitschati Kiel 2006 snail
 Heterostropha - Mathildidae
 Heterostropha - Ringiculidae
 Pleurotomarioidea - Pleurotomariidae
Leptomaria magneti Collignon 1949 snail
 Vetigastropoda - Discohelicidae
Delpeya cottreaui Collignon 1949 snail
 Trochoidea - Turbinidae
 Cerithioidea - Metacerithiidae
 Cerithioidea - Cryptaulacidae
 Architaenioglossa - Ampullinidae
 Epitonioidea - Nystiellidae
 Neogastropoda - Paladmetidae
 Sorbeoconcha - Aporrhaidae
Tessarolax retusa Sowerby 1836 snail
Latiala besairiei snail
> 200 specimens
 Pseudomelanoidea - Pseudomelaniidae