224 THE POPULAR SCIENCE MONTHLY. 



sands and muds, and tilted up and worn down, during the evolu- 

 tion of their present form. There is a quarry at Meriden where 

 one lava-sheet may be seen lying directly upon the scoriaceous, 

 ropy surface of an older one. Evidently, the region has witnessed 

 volcanic action, as the ash-bed implied. Perhaps we fail to recog- 

 nize the cone at the point of outburst because it has been partly 

 worn away. There are many volcanic regions where the eruptive 

 action is not so recent as in Auvergne, and where the cones are 

 consequently somewhat out of repair ; deep gulleys furrow their 

 sides and destroy their symmetrical form. Something of this may, 

 indeed, be seen in Auvergne, for the volcanoes there are not all 

 of the same age. Some are sadly wasted, and are recognized 

 as volcanoes only because their remnants of lava-flows and ash- 

 beds all slope away from a central lava-mass, which marks the 

 place of the vent. It is chiefly in this way that the Madeira Islands 

 differ from the Azores ; the latter possess many cones of regular 

 form, but the older volcanoes on the former are deeply dissected ; 

 so much so that it is difficult to reconstruct the original cones 

 from which the present rugged hills and ridges have been carved 

 out. The same contrast may be seen on a grand scale in the 

 Hawaiian Islands, as described by Dana. The most southeastern 

 of the group is the most recent. It is the largest, and is in the 

 best repair; not a volcanic cone of the usual steep-sided form, 

 indeed, but of long, smooth, gentle slopes, because its lavas were 

 too liquid when erupted to stand on steep slopes such as are 

 formed by heaps of ashes and cinders. Other islands farther to 

 the northwest in the same group are mere wrecks; their edges 

 are cut off by the waves, forming great sea-cliffs, their slopes are 

 scored by deep ravines and canons, and their once even profiles are 

 replaced now by sharply notched outlines. Yet nothing of even 

 those angular forms is to be found about Meriden. If the absence 

 of the cone from which the ashes came is due to wearing away, 

 it must truly have been worn out. 



There is, however, another method of disposing of volcanoes 

 that has been practiced in Italy. The cone has either been blown 

 to pieces and scattered by violent eruptions, or has been allowed 

 to sink down by the withdrawal of lava from beneath its founda- 

 tions. In either case, a great basin, often holding a lake, marks 

 the site of the lost cone. There are several lakes of this kind in 

 Italy — Trasimeno, Bolsena, Bracciano, and others ; Sumatra pos- 

 sesses some huge basins of the same pattern ; but there are no 

 such basins in Connecticut. There are no lakes at all near Meri- 

 den, and the lakes in the back country are only old valleys ob- 

 structed by glacial drift. 



There is an account of an old volcanic region out in New Mex- 

 ico that may, perhaps, guide our search. In the district of the 



