346 THE POPULAR SCIENCE MONTHLY. 



and representations of bowlders possess but little interest other 

 than what pertains to peculiarities of size, shape, and location ; 

 while the agencies mainly concerned in the formation, movement, 

 and distribution of the bowlder, as well as of the ordinary pebble, 

 which is a miniature bowlder, have long ceased to be matters of 

 controversy. With those not versed, however, in geological evi- 

 dence and reasoning, the case is far different. To most of such, 

 the attributing of the phenomena under consideration to the 

 motor power of ice seems so fanciful and unnatural that the 

 agency of the Indian (as has come within the experience of the 

 writer) has appeared more reasonable. But if any one thus doubt- 

 ing will but acquaint himself with the present condition of 

 Greenland, where we have a continental area covered with a sheet 

 of ice of immense thickness — a mile or more, doubtless, in many 

 places — continually accumulating through almost constant at- 

 mospheric precipitations, and moving, through the weight and 

 pressure of such increments of snow and ice, with almost irresisti- 

 ble force from the center of such continent to its sea or coast line, 

 and then in imagination transfer and reproduce such conditions 

 (which are undoubted actualities) over the whole of the northern 

 United States and Canada, he will be abundantly satisfied that 

 the most striking of bowlder phenomena constitute but a very 

 small measure of the forces that were concerned in their produc- 

 tion and were concurrently exerted to modify the earth's surface 

 — even to the extent of removing mountains. 



It will also widen the sphere of interest in this subject to refer 

 to the humbler but at the same time most instructive memorials 

 of the Glacial period, which are, as it were, associated with the 

 bowlders, and help to conceal the barrenness and desolation of 

 the " drift " ; namely, the pretty flowering plants like the " dan- 

 delion" and the "trailing arbutus," and others, which are be- 

 lieved to have come down in the Glacial period from their natu- 

 ral habitat in the far north to our present temperate zone, and 

 to have remained, after the disappearance of the ice, with the 

 bowlders as if to keep them company. Recent explorers of 

 Greenland tell us that wherever in little sheltered nooks upon 

 its dreary coast the ice and frost relax sufficiently in the brief 

 summer to admit of any vegetation, these j^lants grow and flower 

 most luxuriantly, while in their foreign homes they seem, as 

 every one knows, to choose those times and temperatures for 

 blooming and fruition — i. e., in the early spring — which are most 

 in accordance with the conditions of their origin and primal ex- 

 istence ; thus apparently reasserting their ferae, naturae, as did 

 the old vikings when associated with the more delicate types of 

 southern latitudes. 



