One cannot help observing the scarcity of _sand_[10] on the beach. The only adjacent material to build this beach is clay, which here contains a small quantity of sand and some concretions containing lime. The sickle shape of Button Bay keeps most foreign sand from the beach. The small patches of sand present soon give way to _blue clay_[11] which, in many places, forms the base of the beach. This blue clay can also be seen in the base of the bank in the southern portion of the Park, where it underlies and is therefore older than the _brown clay_.[12] Actually very little of the blue clay is exposed in the Park. From other locations along the shore of Lake Champlain and in the more inland areas of the Champlain Lowlands geologists have found many clues to help our understanding of its history. [Illustration: Figure 9A. View of the Brown Clay at the base of the clay-cliff, Button Bay State Park. For scale, note the small ballpoint pen resting on top of ledge (left of center). A close-up view of this ledge (pen in same location) is seen in Figure 10.] [Illustration: Figure 9B. Close-up view showing general characteristics of the Brown Clay. Notice the vertical cracks in the clay. These cracks or joints are very common in the clays of this State Park.] In August 1849 the incomplete skeleton of a _whale_[13] was found in a railroad cut being excavated for the Rutland and Burlington Railroad. This cut was located approximately 12 miles south of Burlington and a mile east of Lake Champlain. The significant fact about this “find” is that these bones were found in the same type of blue clay that occurs at the beach in Button Bay State Park. Clam and oyster shells (Pelecypods) were found in association with the whale bones. These _pelecypod shells_[14] and the whale bones show that these animals lived and died in cold marine waters. Lake Champlain today is a fresh-water lake and the fish and other organisms in it are those of fresh, not salty water. Yet the blue clays (and we are soon to learn, the brown clays) hold evidence proving the existence of sea water in an area where a fresh-water lake is found today. Can this be explained? The brown clay forms most of the Park’s clay banks (see Figs. 9A and 9B ). It can be examined easily by the visitor. The bank is composed of clay and variable amounts of _fine sand_[15] in thin lens-shaped bodies. The hard dry outer clay, if rain has not just fallen, of the upper 15 feet of the bank appears light brown or tan-white and commonly contains interspersed white and blue streaks. In the section of the bank which was the object of detailed study, two conspicuous _convoluted beds_[16] were found, one 5 feet above the beach, the other nearly 2 feet above the first.