Glacier IVork. — Scott. 
253 
number of observations 1666 are accredited to the New England 
states, New Hampshire standing first with 700. Of individual 
states other than those O'f New England, New York is first with 
225, Ohio next with 154, then Pennsylvania, 147, and Wiscon- 
sin, 120. The difference in number of observations is shown 
to be due to several factors. 
First, the irregularity of drift distribution is such that cer- 
tain localities ma)- have abundance of expoised rock surface, as 
in New England, while in others these surfaces are buried so 
far beneath the drift as to preclude observation. 
Secondly, post-glacial decay of the scored rock surfaces 
has doubtless occurred in areas where the rocks were covered 
bv a porous layer of material which admitted air and water. 
Finally, unequal diligence in examination of rock surfaces, 
and unequal distinctness of scorings due to the texture and com- 
position of certain rocks. 
On the whole, however, the glacial marks are found to be 
more abundant in the northern portion of the drift area than 
in the southern, aixd are more prevalent and of greater magni- 
tude north of the limiting moraines of the later epochs than 
south of them. 
Turning now to similar phenomena in Europe it appears 
that striae were observed upon limestone as early as 1836, 
though little attention was given them until 1875 when their 
significance was pointed out by the Swedish geologist profes- 
sor Otto Torell. Since then rock striae have been found in 
various places where the rocks are of a sufficiently hard nature 
to retain them. Owing to the chalky character of the rocks in 
Denmark and North Germany, one looks in vain there for rock 
striae, but north of this area, and farther south also these mark- 
ings are more or less abundant. Such glaciated surfaces in- 
cluding polished roches moutonnees "prove that the great plain 
of Europe has been traversed by 'inland ice' flowing from Scan- 
dinavia and the Baltic." "Along the fjords of Norway," in 
the north also, says Geikie. "the ice worn surfaces may be 
seen slipping into the water, smooth, bare, polished, and 
grooved, as if the ice had only recently retreated." 
The immense power of transportation by the ice sheet is 
perhaps best shown by the erratics, often of hundreds of tons 
weight, which have been moved in some cases for great distan- 
