Published online by Cambridge University Press: 01 May 2009
In December last Dr. C. A. White, Palæontologist to the U.S. Geological Survey, sent me a small packet of siliceous Ostracoda, obtained by dissolving in dilute acid some pieces of an impure limestone from the Jurassic “Atlantosaurus Beds” near Cañon City, Colorado. These strata are of freshwater origin; and, besides the wonderful Dinosaurian and Mammalian fauna, which Prof. O. C. Marsh has published, they contain, Dr. White informs me, Unio, Limnæa, Planorbis, and Valvata, all of modern types. In the impure limestone with Ostracods, and in associated layers, these Gasteropods are found also in a silicified state, and the Dinosaurian fossils occur both above and below them.
page 145 note 1 This Plate was drawn with aid of a grant from the Royal Society for the illustration of fossil Ostracoda.
page 146 note 1 Some of the English specimens are more constricted than shown in the figures and descriptions, op. cit. p. 345.
page 146 note 2 The transverse sulcus impressed on or near the mid-dorsal region of each valve is characteristic also of Linmieythere and occurs in some other recent Ostracods of estuarine and freshwater habitats, namely, Cyprideis (Cytherideii), and one Cypris (C.gibba, Kamdohr).
page 147 note 1 Referred to the Neocomian by Dr. A. C. White in a work prepared by him for publication by the Brazilian Government.