Disappointment Bay Formation

The Disappointment Bay Formation is a geologic formation in Nunavut, extending from Ellesmere Island in the east to Bathurst Island in the west. It preserves fossils dating back to the Devonian period, primarily of invertebrates.

Fossil Content Fish Vertebrate remains are rare in this formation. Indeterminate spine fragments are found throughout the Lowther Island off-reef limestones but are rare. A 2-centimeter wide fragment found in the 2 m-level ammonoid bed of Young Island may represent a cyathaspidid.

Invertebrates

Bivalves Genus Species Presence Material Notes ImagesEoschizodus?E.? sp.Lowther Island"Two small silicified internal moulds."Very small shell, maximum 3 millimeters in length.GosseletiaG. n. sp.Lowther Island"One small complete specimen, 19 single valves, all silicified" Palaeoneilo P. n. sp. Lowther Island "One complete articulated specimen and 15 isolated valves, all silicified".ParacyclasP. proaviaLowther Island6 articulated silicified specimens. Shell up to 45 millimeters long.PhenacocyclasP. n. sp.Lowther Island"Four complete specimens, one shell fragment, all silicified".A lucinid up to 20 millimeters across.PraecardiumP. sp.Young Island, 2m.3 partially exposed internal moulds.Protomya?P.? n. sp.Lowther Island14 silicified specimens."Elongate, oval, ratio of length to height about 2:1". This species cannot be conveniently placed in any genus and is only tentatively placed in Protomya, and alternatively recalls Dystactella subnasuta.SolemyaS. (Janeia) sp.Young Island, 2 m interval, some specimens preserved in near life-position with anterior directed upwards.15 complete to near complete internal moulds, some retaining shell material.

Brachiopods Genus Species Presence Material Notes ImagesAmbocoeliidaeAmbocoeliidae indet.Lowther Island, lower off-reef strata.A few dozen specimens on hand-samples.AncillotoechiaA. rexLowther Island off-reef strata, 45 m (2 specimens), 65 m (23 specimens).25 silicified, articulated specimens.A trigonirhychiid.AthyrhynchusA. susanaeLowther Island off-reef strata, from about 24–30 m.About a dozen specimens. A leiorhynchid. AtrypaA. sp. ALowther Island reefs, Facies 2 (5 specimens), Facies 3 (1 specimen).6 specimensAn atrypid.A. sp. BLowther Island reefs, Facies 1 (10 specimens), Facies 2 (28 specimens).38 specimensAn atrypid.A. sp. CLowther Island off-reef strata, 45 m (11 specimens), 65 m (about 100 specimens).Over 100 specimens, all silicified, and in both articulated and disarticulated condition. An atrypid.CarinagypaC. aseptata"Lowther Island reefs, Facies 1 (33 specimens), Facies 2 (134 specimens), Facies 3 (3 specimens)".A gypidulid.CarinatinaC. lowtherensisLowther Island reefs, mostly in Reef Facies 2 (3 specimens from Facies 3).About 120 specimens. An atrypid.CassidirostrumC. radiatumLowther Island off-reef strata, 45 m (1 specimen), 65 m (2 specimens).3 silicified, articulated specimens.A trigonirhynchiid. "Chonetes""C". sp. ALowther Island off-reef strata, 65 m.2 silicified brachial valves.A chonetid."C". sp. BLowther Island off-reed strata, 45 m (1 specimen) and 65 m (4 specimens).5 silicified valves, plus a few fragments.A chonetid."C". sp. CLowther Island off-reef strata, 65 m.35 silicified valves.A chonetid.CymostrophiaC. sp.Lowther Island reefs, Facies 2.20 specimens. A stropheodontid.cf. Desquamatiacf. D. sp.Lowther IslandAn atrypid.?Devonochonetes?D. sp.Young Island, 2 m."A single, small (4 mm along hingeline) specimen, demonstrating the pedicle valve exterior".A chonetid. May be conspecific with the Lowther Island "Chonetes" sp. C, but inadequate preservation of both hampers meaningful comparison. ElythynaE. transversa intermediaLowther Island, off-reef strata. One specimen from Young Island.About 100 specimens in hand sample.A reticulariid. E. kingiLowther Island upper off-reef strata.About 100 silicified specimens, both articulated and disarticulated.A reticulariid. GlossinulinaG. khodalevichiLowther Island reefs, Facies 2.17 articulated specimens. An uncinulid. LingulaL. sp. Young Island 2 m"One small (3 mm) complete brachial valve, and a few valve fragments". A lingulid.?Megastrophia?M. sp.Lowther Island reef R-4, Facies 2 (locality R-4 no. 27)A single, nearly complete, exterior pedicle valve.A stropheodontid. OrbiculoideaO. sp. ALowther Island, Reef R-7, upper Reef Facies 2 (locality R-7, N-5)."A single, well-preserved pedicle valve showing the interior surface".A discinid.O. sp. B?Young Island, 2 m."A single, partially-crushed pedicle valve (external surface exposed), and a few valve fragments".A discinid.?ParachonetesP.? sp.Lowther Island reefs, Facies 2.5 poorly-preserved specimens.A chonetid.PhragmostrophiaP. cf. P. merriamiLowther Island off-reef strata, Young Island.Dozens of specimens from Lowther Island, about 20 specimens from Young Island.A pholidostrophiid.PunctatrypaP. sp.Lowther Island off-reef strata, 45 m (4 specimens), 65 m (3 specimens).7 silicified, articulated specimens.An atrypid.SchizophoriaS. nevadaensisLowther Island reefs, Facies 1 (2 specimens), Facies 2 (9 specimens).A schizophoriid.Schuchertella"S." cf S. nevadaensisLowther Island reefs, Facies 3 (locality R-8 no. 37).A single articulated specimen. A schuchertellid. SpinatrypaS. (Invertrypa) sp.Lowther Island reefs, Facies 2 (39 specimens), Facies 3 (1 specimen).40 specimens.An atrypid.S. (Invertrypa) sp. ALowther Island off-reef strata, 65 m (1 specimen from 45 m).About 150 silicified specimens, about half of which are articulated.An atrypid.SpirinellaS. ultimaLowther Island reefs, Facies 2.5 specimens. A reticulariid.SpurispiriferS. vijaicoidesLowther Island reefs, Facies 2.3 specimens. A reticulariid.VagraniaV. sp.Lowther Island, reef R-2, Facies 3 and reef R-8, Facies 3.Many dozens of external moulds from reef R-2, Facies 3, and 8 partial, poorly-preserved specimens from reef R-8, Facies 3.An atrypid.

Cephalopods Genus Species Presence Material Notes ImagesBactritesB. sp.Lowther Island3 small silicified fragments.A bactritid.LobobactritesL. ellipticusYoung Island and Lowther IslandNumerous large, incomplete specimens from Young Island, and juvenile remains from both Young and Lowther Island.A bactritid.MimagoniatitesM. nearcticusYoung Island and Lowther IslandAbout 100 specimens from Young Island and numerous more from Lowther Island of both mature and juvenile individuals.An ammonoid. Palaeogoniatites Palaeogoniatites aff. P. janus Lowther IslandA single mature specimen along with numerous silicified shell fragments, protoconchs and early whorls. An ammonoid.

Corals Genus Species Presence Material Notes ImagesAlveolitesA. sp."Lowther Island reefs, upper Facies 1 (uncommon), Facies 2 (abundant), Facies 3 (common lower; rare upper)".About a dozen nearly complete coralla and numerous fragments. An alveolitid. FavositesF. sphaericus Lowther Island, reef R-3, upper Facies 2."A single, 15 cm-wide corallum". A tabulatan. F. sp.Lowther Island reefs, upper Facies 2 (reefs R-4, R-3 and R-7)."3 partial coralla and numerous fragments".A tabulatan, coralla can reach up to 2 meters across.Gracilopora?G.? sp.Lowther Island reefs, lower Facies 3 (reef R-8)."3 partial coralla, and about a dozen other occurrences of solitary branches, all slabbed surfaces".A pachyporid."Hexagonaria""H." sp.Lowther Island, off-reef strata."A single, well-preserved corallum". RoemeriporaR. progenitor?Lowther Island reefs, Facies 3 (reef R-8).2 partial coralla.R.? sp.Lowther Island reef R-2, Facies 3.4 poorly-preserved coralla.The most abundant coral framebuilder in Reef Facies 3.SalairiaS. sp.Lowther Island reefs, upper Facies 2 (R-4), Facies 3 (R-8, R-2).About a dozen specimens. Syringoporidae indet.Lowther Island reef, R-2, Facies 3."2 small (about 10 cm across) coralla, vert poorly preserved".

Sponges Genus Species Presence Material Notes Images ClathrodictyonC. ellesmerense Reef R-8, Facies 3 (complete specimens and fragments); reef R-4, uppermost Facies 2 (fragments only)"."4 complete to nearly complete coenostea, and numerous fragments". HindiaH. sphaeroidalisLowther Island, 65 m."A single, small (diameter 1 cm) silicified specimen".A lithistid.SalairellaS. primaReefs R-2 and R-8, Facies 3; reefs R-3 and R-4, upper Facies 2.5 complete to nearly complete coenostea, and numerous fragments.A stromatoporoid.

Tentaculita Genus Species Presence Material Notes Images Nowakia N. sp. ALowther Island"10 partial to complete, isolated, silicified specimens".A nowakiid.N. cf N. praecursorLowther Island"A few hundred isolated, silicified specimens".NowakiidaeNowakiidae n. gen n. sp.Lowther Island 45 m."4 isolated, silicified specimens, 2 partial, 2 complete".New genus and species, probably represents an earlier offshoot of the Nowakia lineage, perhaps derived fromTurkestanella (Nowakia) acuaria.StyliolinaS. cf. S. sp. AYoung Island and Lowther Island."About 100 isolated silicified specimens preserving the proximal 3-4 mm (Young Island). Many hundreds of complete silicified specimens (Lowther Island)".A styliolinid.UniconusUniconus cf. U. orbiculusYoung Island and Lowther Island.A tentaculitid.ViriatellaV. n. sp.Young Island 2 m.4 isolated, silicified specimens. ViriatellinaV. aff. V. pseudogeinitziana"Young Island 2 m, Lowther Island 45 m, and reefs R-10, R-7 and R-4 (reef facies 1, 2, and 2A)".A nowakiid.VolynitesV. triannulatusLowther Island."About 100 isolated, silicified specimens".A tentaculitid

Trilobites Genus Species Presence Material Notes Images ArctipeltisA. canadensis Lowther Island reefs, samples R-7 no. 5, R-4 no.4b, R-10 no.8 (all Reef Facies 2).3 partial to nearly complete pygdia. Originally referred to Weberopeltis aff. arcticum. AstycorypheA. n. sp.?Lowther Island, reef R-10, sample locality no.3 (Facies 2A).Numerous partial to complete cranidia and pygdia.KielaniaK. triabsidataSchizoproetoidesS. ellesmerensisLowther Island, off-reef section LLW-4 (40 m level), Young Island 2 m."One complete enrolled specimen, and two separate pygdial impressions".A proetid.

Other invertebrates Genus Species Presence Material Notes ImagesHyolithesH. n. sp.Lowther Island, reef R-10, Reef Facies 2.A single complete specimen.Robust conoid shell measuring 25 millimeters long. PlagioglyptaP. sp. Lowther Island off-reef strata"About 100 silicified specimens". A dentalioid scaphopod.

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