This is a rare piece in the world of Native American jewelry collecting. Few manta pins  remain and even fewer with solid silver stick pins remain. Manta pins were used as a shoulder closure for the Pueblo woven dress or shawl called a Manta. Many of the Pueblo tribes wore Mantas and had slight variations in design. These pins started to disappear as the style of dress began to change and the need for them went to the way side. Most Manta pins of this particular style are made from coin silver. This pin was collected in the early 1970s in the southwest. 

Little has been written about these pins, but they are referenced in Indian Silverwork of the Southwest, Illustrated-Volume One (Pg 115, Plate 4) by Harry P. Mera

Total Length 2 ½"; Face of Manta Pin: L 1 ⅜" : W 1⅛"