20 FE. D. Chester—Bowlder Drift in Delaware. 
Some of these latter are enormous in size. One ba elas of 
Besides these larger examples, the whole bank is completely 
filled with bowlders of iron-stone, large and small, distributed 
irregularly throughout the confused mass, and it is this fact 
which gives the deposits their economic importan 
One of the most interesting facts with regard is the geology 
of these hills is the occurrence of great bowlders of aoieae 
which are thickly strewn over every part and even in the mea- 
dow land to the north, and just at the foot of the hills the 
ground is so covered with them, that one is immediately re- 
sca of similar scenes in more northern latitudes. At the 
beginning of the ascent I came across the largest bowlder 
of g See yet found ; it measured thirty-seven feet in circum- 
ference, and another near by, sixteen. At the top, the west 
side of one of the hills was so literally strewn with bowlders 
that one could not step without walking on Reng one of 
these measured twenty-five feet in circumference and numerous 
others were not less than fifteen, all the fades: varying from 
this size down. 
I have to note here that I have found bowlders both to the 
north and ten miles to the south of these hills, some of them 
ela in size from fifteen to twenty feet in circumference 
these cases of bowlder examination, I have not suc- 
seeded in patti: distinct glacial scratches, although patient 
search was kept In a few instances parallel striz were 
seen, but these were so obscured by the extreme weathering of 
bowlders that their true nature remains a question of doubt 
In almost every case the surfaces of the rocks were FO so 
weather-worn or moss-covered as to obscure all evidence with 
oe cine As to the _ fag how bowlder 
geolgi that: bowlders have been foand as « far south as the 
uthern States, and that their presence in these localities is 
saitaiaed by supposing that they were transported by floating 
icebergs which found their way to the south at the close of the 
Glacial period; hence it seems to be the most probable theory, 
that not only the solitary bowlders found in Delaware, but that - 
the materials of these two hills were transported southward by 
floating ice during the Champlain period. 
e entire want of stratification observed in both hills would 
tend to show that the materials were dropped pell-mell from 
