KEPOBT OF NATIONAL MUSEUM, 1920. 113 



the subject of investigation, and a description of the mineral locali- 

 ties of Yuma County, Arizona, has been published. 



In paleontology, Secretary Walcott has completed and published 

 the results of his .study of the Middle Cambrian algae from the Bur- 

 gess shale, fauna, collected during the last ten years, a preliminary 

 report on which appeared in 1912, and a similar study and report on 

 the Spongiae from the same horizon and region. In addition he 

 has prepared two papers, one a further study of the appendages of 

 the trilobite, and the other a study of the problematic Middle Cam- 

 brian crustacean, Marrella, discovered in the Burgess Pass fossil 

 quarry. 



Mr. Frank Springer has continued his study on the fossil echino- 

 derms and completed the proof reading on his monograph of the 

 Crinoidea Flexibilia in course of publication by the Smithsonian 

 Institution. 



Dr. E. O. Ulrich has continued his studies on the Ozarkian and 

 Cambrian fossils, and with Dr. C. E. Resser made a preliminary 

 examination of the large collection of Cambrian forms from Wis- 

 consin, mentioned elsewhere in this report. Doctor Resser has con- 

 tinued his bibliographic index of Cambrian fossils. 



Dr. H. S. Bassler, in association with Ferdinand Canu, completed 

 his monographic study of the fossil Bryozoa of the West Indies, the 

 results appearing in a publication of the Carnegie Institution. They 

 have also continued investigations on the fossil and recent Bryozoa 

 i the Museum collections. 



Dr. T. W. Stanton has continued work on the invertebrate faunas 

 of the Comanche series of the Cretaceous preparatory to a monograph 

 on the subject, and has completed that on the fossils of the Cannon- 

 ball member of the Lance formation of the Dakotas. 



A report has been prepared by Dr. Mary J. Rathbun on the Cre- 

 taceous decapod crustaceans of Tennessee and one on the same 

 group from the Pacific Coast states and British Columbia is pro- 

 gressing. Doctor Rathbun has also identified the crustaceans ob- 

 tained in 1919 in the Dominican Republic by Dr. T. W. Vaughan, and 

 prepared for publication descriptions of three new species. 



Dr. F. II. Knowlton has finished the study of the Museum's col- 

 lection of fossil plants from the Denver formation, and Dr. W. H. 

 Dall has reported on the Pleistocene and Eocene fossils of the 

 Arctic coast collected by the Stefanson expedition. His report on 

 the fossils of the Nome Peninsula has been issued by the Geological 

 Survey, and the proofs read on his revision of the recent and Ter- 

 tiary Brachiopoda. A list of the marine shell-bearing mollusks of 

 the west coast of America from San Diego to the Arctic Ocean has 

 been prepared and is now in the hands of the printer. Work has 

 9525°— 20 8 



