Outdoor Map P e n r o s e P l a c e GS A Garde n Eaton Terrace M A I N E N T R A N C E 9 OUTDOOR EXHIBITS Outdoor Exhibits Society Plaque Ar ri ving at GS A you will notice that our building is situated on two scenic acres with an additional two acres sur rounding the building populated by a variety of indigenous trees Next to the sidew alk to the right of the front park ing lot facing west is the original bronz e plaque now set in moss roc k that welcomed visitor s to the S ociety s fr st headquar ter s building in New Y ork more than a hundred year s ago The stone and its emplacement are a gift from Luna B Leopold Univ ersity of California at Berk ele y and a for mer president of the Society Dor is Malkin Cur tis Memor ial Plaque and Color ado Blue Spr uce Doris Cur tis 1 91 41 991 fr st woman president of the Geological S ociety of America w as widely admired for her spirit her energy and her contributions to science and to the geoscience community During her career in the petro leum industry academia and consulting she held leader ship roles in a num ber of prominent geological and scientifc org anizations The plaque and the Colorado blue spruce w ere donated b y GSA staff Str omat olit e L ocated in the roc kbed to the right of the front parking lot adjacent to the w alk w ay this two ton specimen is from the 1 8 billion year old K ona Dolomite in the Chocolay Group of the Marquet te R ange Supergroup near Neg aunee Mic hig an The laminated domes in this ancient roc k are stromatolites They were built layer by layer almost 2 billion year s ago by colonies of blue green alg ae li v ing at the bot tom of a shallow sea As par t of their life processes the alg ae secreted calcium carbonate the same mineral that forms limestone The cal cium carbonate set tled in thin layer s that the alg ae grew o ver and through T in y grains of sediment were trapped in the layer s too When the sediments were later con ver ted to roc k they formed an impure limestone Later still they metamorphosed into dolomitic marble that still displays the stromato lites that the alg ae built Located b y Da vid K Larue Gift from A Lindberg and Sons Inc of Ishpeming Michigan through LL Sloss Sundial Carved in a polished slab of serpentine the sundial to the lef t of the front w alkw ay is a small but signifcant mark er leading to the building The sundial shows the exact time only four days eac h year 1 5 April 1 4 J une 1 S eptember and 25 December During the summer it is incor rect by as muc h as 65 min utes on 26 J uly in winter it is of f by as muc h as 1 64 minutes on 3 No vem ber In addition to these er ror s whic h are related to Ear th s orbit the time shown is a full hour of f during daylight saving periods The origin of the stone is uncertain but it w as probably collected for the Smithsonian Institution b y George Merrill The stone itself w as a gift from the US National Museum of Natural History Smithsonian Institution W ashington D C through George Switzer and Harold H Banks Jr Its transfguration into a sundial is the gift of August Goldstein Jr T ulsa Oklahoma for mer treasurer of the Society Calculations design and cutting w ere b y Milton Erickson Erickson Memorial Co Denv er Colorado