222 THE POPULAR SCIENCE MONTHLY. 



the eruption, arriving here before the ashes, plunging down after 

 its lofty flight through the air, and sinking into the mud at the 

 bottom of the water. In this it recalls the reptilian footprints 

 that have made the sandstones of the valley famous. The old 

 reptiles walked over the mud-flats and left their heavy j)rints on 

 the surface to be buried under the next layer of mud ; the lava 

 block fell into the soft sandy mud and made its print, where it 

 still lies. Long may it rest undisturbed ! A poor indication of it 

 is presented in Fig. 1, copied from a photograph by a friend in 

 New Britain, Conn. All this was much more evident and more 

 easily interpreted than those who try to learn geology from books 

 are disposed to believe. Indeed, one of the students with me ex- 

 claimed : " This is the most realistic thing I ever saw ; I had no 

 idea that it could be so plainly made out." The ledge has been 

 visited by hundreds of persons from Meriden and the surrounding 

 towns, and a well-beaten j^ath now leads up to it from the road. 

 I have taken parties of students there every summer since then, 

 and hope to do my share toward beating down that path for 

 many years to come. But although the meaning of the ash-bed 

 is plain enough, there is a question suggested by it that is not so 

 easily answered. Where is the volcano from which the ashes and 

 bombs were blown out ? 



The same question has arisen in other countries. For example, 

 in central France, in Auvergne, there are chalky beds that were 

 once a soft white mud, and in these lie bombs of lava, bending 

 down the layers on either side ; manifestly again the result of a 

 bombardment from some adjacent volcano. In the same district 

 there are beds of ashes and flows of lava, all indicating volcanic 

 outbursts in their vicinity ; but when the question is there asked — 

 Where are the volcanoes from which these products came ? — it is 

 easily answered, for many volcanic cones still stand up in plain 

 sight near by ; the lava-flows may be traced up to their bases, the 

 craters are still visible at the summits, and although no record 

 exists of their eruptions, it is manifest that at a relatively recent 

 prehistoric period these cones exhibited a brisk activity. I 

 walked over them a dozen years ago ; they make a delightful 

 strolling and sketching ground, and I remember well lunching 

 with a shepherd on one of their sunny slopes, and answering his 

 questions about distant America (Fig. 2). 



We may look in vain for volcanic cones in the neighborhood of 

 our Meriden ash-bed bluff. There are hills and ridges all around, 

 butnowhere can we see the smooth and characteristic concave slopes 

 of a volcanic cone. To the south, there are several symmetrically 

 rounded hills, but they are convex, not concave, on the side, and 

 an examination of the road-cuts made in their slopes shows them 

 to be of anything but volcanic origin. They are " drumlins/' hills 



