SECRETARY'S REPORT 15 



all levels of the Beaufort series (Permo-Triassic) and document the 

 therapsid adaptive radiation of that time and also the strong trend 

 toward mammalian organization for which these animals are noted. 

 The therapsids illustrate an important phase in vertebrate evolution, 

 which has heretofore been unrepresented in the national collections. 

 The fossils are of high quality, consisting of about 40 complete or par- 

 tial skeletons with the remainder being skulls. The collection was 

 made by associate curator Nicholas Hotton III and by James W. 

 Kitching, of the Bernard Price Institute for Paleontological Research, 

 University of the Witwatersrand, Johannesburg. Noteworthy of 

 mention also are the skulls of about 200 individuals of the Permian 

 amphibian Diplocaulus collected by Dr. Sergius H. Mamay, of the U.S. 

 Geological Survey, and Dr. Walter W. Dalquest, of Midwestern Uni- 

 versity, in terrestrial deposits of the Vale formation in Texas. An- 

 other outstanding addition to the collections is a 4-ton shipment of 

 skeletal remains, almost all of the mammoth Mammuthus coIuTubi^ 

 from a spring deposit on the ranch of Charles I, Lamb near Littleton, 

 Colo. These were collected by a joint archeological-paleontological 

 party under the supervision of Dr. Waldo R. Wedel and Dr. C. L. 

 Gazin. Particular mention may be made of stratigraphically im- 

 portant accessions of Eocene and Paleocene mammals from new locali- 

 ties in the Fossil, Wind River, and Green River basins of Wyoming, 

 and of early Oligocene mammal jaws and teeth from Pipestone 

 Springs in Jefferson County, Mont., collected by curator C. L. Gazin 

 and Franklin L. Pearce. 



Science and technology. — Examples of the rotating mirrors used by 

 A. A. Michelson in his experiments in the determination of the velocity 

 of light were obtained in the division of physical sciences from Preston 

 Bassett and from Mount Wilson and Palomar Observatories. Dr. 

 Henry E. Paul donated telescopes representing the work of Alvan 

 Clark and Sons and John Brashear. Two of the earliest extant ex- 

 amples of photographs of the sun and moon, made by the pioneer 

 scientist and photographer John W. Draper, were obtained from New 

 York University. A group of 12 globes painted to illustrate as many 

 geophysical phenomena, from Prof. Rhodes W. Fairbridge, of Co- 

 lumbia University, was added to the geophysical collections. Gulf 

 Research & Development Co. contributed the pendulum apparatus for 

 relative gravity determination which was developed by them in 1929. 

 John Kusner contributed a repeating circle of the type used in the 

 1830's in the first geodetic surveys in this country. 



A reproduction of the celebrated clock of Giovanni de Dondi, con- 

 structed from contemporary 14th-century manuscript descriptions, 

 was acquired in the division of mechanical and civil engineering. The 

 original clock, which disappeared from historical account over 400 



