tion staff was devoted to work on exhibits. In addition, 35 plaster 

 casts of specimens were made and shipped to universities, colleges, 

 and other museums. To facilitate handling and storing of the Mecca 

 specimens (see page 53) a special rock-saw was designed and built 

 by the personnel of the Division of Paleontology. 



Exhibits— Geology 



Seventeen exhibits, all devoted to mineralogy, were completed and 

 installed in the new Hall of Meteorites and Minerals (Hall 35). 

 Thirteen of these exhibits consist of minerals arranged systematically 

 according to their structural and chemical relationships. Although 

 the number of specimens exhibited is considerably reduced in com- 

 parison with the old exhibits of minerals, the number of species has 

 been increased, resulting in a more comprehensive representation. 

 Four exhibits are introductory in nature and include: (1) naturally 

 occurring elements, (2) mineral crystals, (3) physical properties of 

 minerals, and (4) an introduction to rocks and minerals. The hall 

 has been closed to the public for the past year, but every effort is 

 being made to complete the mineral exhibits so that the mineralog- 

 ical section of the hall may be open to the public in the spring of 1958. 

 To accomplish this task Harry E. Changnon, Curator of Exhibits, 

 Assistant Henry Horback, and Preparator Henry U. Taylor, in co- 

 operation with Associate Curator Forslev, are devoting their full 

 time to the planning, preparation, and installation of the new ex- 

 hibits. Drawings of crystal structures, diagrams, and an oil painting 

 of Death Valley are the competent work of Miss Maidi Wiebe, De- 

 partmental Artist. 



The major effort in the paleontological laboratory has been di- 

 rected toward the completion of the partial mounted skeleton of 

 Brontosaurus in Hall 38. The bones of the neck, shoulder girdle, and 

 forelimbs have been prepared, the re-enforcing supports are ready, 

 and final assembly of the skeleton is under way. It is hoped that 

 the mount will be completed early in the spring of 1958. We extend 

 our sincere thanks to Joseph T. Ryerson and Son, Incorporated, and 

 to W. M. Sikkema, one of the structural fabricating engineers of the 

 company, for their assistance in the determination of types and 

 weights of steel to be used for the mount of the brontosaur skeleton. 



Five special exhibits were installed in Stanley Field Hall in con- 

 nection with the annual contest and show sponsored by the Chicago 

 Lapidary Club for amateur lapidarists of the Chicago area (see 

 "Special Exhibits" on page 30). 



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