126 ANNALS NEW YORK ACADEMY OF SCIENCES 



PALEONTOLOGY 



Flora of the Morrison Formation 



The following species of cycads from the Morrison formation have been 

 described by Ward: 



Cycadella reedii Cycadella ferruginea 



Cycadella beecheriana Cycadella eontracta 



Cycadella ivyomingensis Cycadella gravis 



Cycadella knowltoniana Cycadella verrucosa 



Cycadella compressa Cycadella jejuna 



Cycadella jiirassica Cycadella concinna 



Cycadella nodosa Cycadella crepidaria 



Cycadella cirrata Cycadella gelida 



Cycadella exogena Cycadella carbonensis 



Cycadella ramentosa Cycadella Jcnightii 



There is also Cycadella utppiensis (Ward) Wieland, Araucarioxylon ? 

 ohscurum Knowlton, and possibly Pinoxylon dacotense Knowlton.^ 



This flora is of no great value in indicating the age of the formation, 

 but it does signify that the climate in which it lived was warm and prob- 

 ably moist in places at least. 



Invertebrate Fauna of the Morrison Formation 



The invertebrate fauna of the Morrison consists of fresh-water pelecy- 

 pods and gastropods, with a few crustaceans. A number of species have 

 been described and considerable material collected. There is nothing 

 in the fauna of any value in determining the age of tlie formation. The 

 following species have been described: 



PELECYPODA 



Unio felcJiii White, On the Fresh-Water Invertebrates of the North 

 American Jurassic. U. S. Geol. Surv., Bull. No. 29, p. 16, pi. 1, figs. 

 1-5, 1886. 



8 The flora is described and discussed in the following works : 



Ward, L. F. Description of a New Genus and Twirty New Species of Fossil Cyca- 

 dean Trunks fi-om the Jurassic of Wyoming. Wash. Acad. Sci., Proc, vol. 1, pp. 253- 

 300, pis. xiv-xxi, 1900. 



Ward, L. F. Status of the Mesozoic Floras of the United States. U. S. Geol. Surv., 

 20th Ann. Rep., pt. 2, pp. 211-747, pis. xxi-clxxix, 1900. 



Ward, L. F. Status of the Mesozoic Floras of the United States. U. S. Geol. Surv., 

 Monograph No. 48, pt. 1, text, 616 pp., pt. 2, plates, 119 pis., 190-5. 



Wieland, G. R. American Fossil Cycads. Carnegie Inst. Wash., Pub. .34, 286 pp., 

 50 pis.. 137 figs., 1906. 



Berry, E. W. Lower Cretaceous Floras of the World. Md. ^Geol. Surv., vol. Low. 

 Cret., pp. 99-151, 1 fig., 1911. 



