[Illustration: Cover Picture: Selected “buttons” from the clay bank along the beach at Button Bay State Park. (×0.8).] THE GEOLOGY OF BUTTON BAY STATE PARK _By_ HARRY W. DODGE, JR. DEPARTMENT OF FORESTS AND PARKS Perry H. Merrill, _Director_ VERMONT DEVELOPMENT DEPARTMENT VERMONT GEOLOGICAL SURVEY Charles G. Doll, _State Geologist_ 1962 THE GEOLOGY OF BUTTON BAY STATE PARK _By_ Harry W. Dodge, Jr. INTRODUCTION Button Bay State Park is located on the eastern shore of Lake Champlain with lake frontage on Button Bay (see maps, Figs. 1 and 2). This Vermont State Park is reached from the nearest large town, Vergennes, by proceeding southwest, toward Addison, on State Route 22A for .25 miles beyond the bridge over Otter Creek, thence, right on the Basin Harbor-Panton road for another 1.4 miles to the first road entering from the right. Turn right on this, the Basin Harbor road, and proceed for 4.5 miles, thence, left for 1.4 miles to Button Bay State Park (see map, Fig. 2, note arrows). A more direct road is planned to connect the Basin Harbor Road with the Park, however, this route has still not been completed. Prior to its present name, Button Bay, the “sickle-shaped bay” on which Button Bay State Park is located was termed _Button Mould Bay_[1]. In “The Journal of William Gilliland” which is found in the “Pioneer History of the Champlain Valley” by Winslow C. Watson, Albany, 1863, and under the date of September 7, 1765, is found an entry which speaks of “his (Gilliland) overtaking ‘_the Governors and other gentlemen_’[2] at Button Mould Bay, and going aboard their sloop.” A book of charts by Captain William Chambers contains one entitled “Baye du Roche Fendue (Split-Rock Bay) and the soundings taken in August 1779.” At the upper corner of the chart is the name “Button Mould Bay.” The first appearance of the shortened version, Button Bay, seems to be in Whitelaw’s map of 1796 which was used as the frontispiece of the Census volume, “Heads of Families, Vermont, 1800.” [Illustration: _FIGURE 1_ MAP OF WEST-CENTRAL VERMONT AND EASTERN NEW YORK] [Illustration: _FIGURE 2_]