Amberleya cf. dilleri Stanton, 1895

Kiel, Steffen, Campbell, Kathleen A., Elder, William P. & Little, Crispin T. S., 2008, Jurassic and Cretaceous gastropods from hydrocarbon seeps in forearc basin and accretionary prism settings, California, Acta Palaeontologica Polonica 53 (4), pp. 679-703 : 683

Amberleya cf. dilleri Stanton, 1895

Fig. 4D .

Material.— One specimen from NW Berryessa (site 10; UCMP 555090 ), and two fragments from the Franciscan Little Indian Valley terrane (site 6) .

Discussion.—These specimens have a stronger second tuberculate cord below the main one compared to Stanton’s (1895) type specimens of A. dilleri , and lacks the nodular subsutural cord of A. morganensis . Because the specimens are rather poorly preserved, we only hesitantly assign them to A. dilleri .

Stratigraphic and geographic range.—Tithonian (Upper Jurassic) to Valanginian (Lower Cretaceous), restricted to seep carbonates at NW Berryessa of the Great Valley Group and Little Indian Valley terrane , Franciscan Complex; California, USA.

Figures

Fig. 4. Late Jurassic and Early Cretaceous eucyclid Amberleya spp. from seep carbonates in California, USA. A–C. Amberleya dilleri Stanton, 1895, type specimens from Paskenta (site 2). A. Spire of juvenile specimen (USNM23074a). B. Spire of large specimen (USNM 23074b). C. Lectotype (USNM 23074c) showing the aperture.D. Amberleya cf. dilleri (UCMP 555090) from NW Berryessa (site 10). E–I. Amberleya morganensis (Stanton, 1895) from Rocky Creek (site 7). E. Lectotype (USNM 23071). F. Spire (CAS 70386) with two tuberculate spiral cords. G. View on flank and basal margin (CAS 70387). H. Spire (CAS 70388) with lower tuberculate spiral largely concealed by succeeding whorl. I. Specimen (CAS 70389) with narrow apical angle. F–I, rubber casts.