Page:History of Barrington, Rhode Island (Bicknell).djvu/18

2 Geologically, Barrington owes its existence to the last glacial period or ice age. Let us trace its formation. The rock stratum which underlies this section is a conglomerate of small pebbles or fine gravels, held together by a grey, blue or black paste or cement. An excellent specimen of this rock may be seen in the only elevated ledge in Barrington, at Drownville, on which the water tank of the Drownville Water Works stands. This ledge contains very coarse pebbles and was thrown up from the general sea or ocean level by the contraction of the earth's crust. Imagine then this aqueous, pudding-like rock lying near the shore of an ancient sea or ocean. Think of the earth cooling down and wrinkling into folds in the process of cooling, and you will, by your mind's eye, see the ocean's bed, breaking its level and some parts of it rising into hills and mountains and some parts sinking into valleys and deep sea channels. The Rhode Island hills and valleys were then formed and all the rocky peaks or knolls were then lifted up, very much higher than we see them to-day. Mount Hope, which is now only about 200 feet in height, may have been twice or three times its present height, when this breaking up of the earth's crust of Rhode Island took place. Call this action, if you like, the fracture or ploughing up of the sea floor on which our town lies. There was nothing then to have been seen but a salt sea and rocky, craggy peaks rising like islands above its surface. The breaking-up ploughshare has done its work. Now we need a great harrow to cut down the rough hills and fill up the shallower water spaces. The great leveller of the earth is the glacier. The ice age came and buried our section under snow and ice to the depth of thousands of feet. In the White Mountain region of New Hampshire, the ice stood as high as the top of Mt. Washington. Europe, Asia and North America were covered under the northern ice sheet as low as Providence, say 40°, north latitude. The ice began to flow southward towards the warmer latitudes, breaking down in its movement the rough crags, the rocky hills, and mountains, grinding the softer rocks to fine clay,