This item consists of 9 lantern slides and 1 black-and-white photograph of Hartley H. T. Jackson's contemporaries circa 1891-1929. The lantern slide plates depict Walter P. Taylor and Harold C. Bryant, 24 July 1910 at Parker Creek, Warner Mountains, Modoc County, California on the Warner Mountain field trip; Harold Elmer Anthony, 1915; Vernon Orlando Bailey, Wilfred Hudson Osgood, Edward William Nelson and Albert Kenrick Fisher; Theodore Sherman Palmer, 1891; Gerrit Smith Miller, Jr., 1897; A. Remington Kellogg and Marcus H. Hanna, 1916; Edward Alexander Preble and Mollie Harper, ca. 1928; Vernon Orlando Bailey, Clinton Hart Merriam, Theodore Sherman Palmer and Albert Kenrick Fisher, 1891; Vernon Orlando Bailey; Hartley H.T. Jackson and Wilfred Hudson Osgood, 1929. Also included is 1 black-and-white photograph of Jas H. Clark riding a yak.