EXPERIMENTS WITH AVAILABLE ROAD-MAKING 
MATERIALS OF SOUTHERN WISCONSIN. 
ELLSWORTH HUNTINGTON. 
The subject of road-making has been almost entirely neglected 
in this country in so far at least as its geological features are 
concerned. Some attention has been paid to engineering prob¬ 
lems in their relation to roads, but almost nothing has been done 
to find out the value of different materials in the construction 
of a cheap yet serviceable surface on our common roads. In most 
parts of the country the only practicable way of road-making 
which will be good at all times of the year is to put a crust of 
crushed stone from six to twelve inches thick on a foundation 
made of whatever soil the country happens to furnish. The most 
important conditions which the road-material must satisfy are 
cheapness, hardness or capacity for resisting the wear of horses 
and of wheels, readiness in cementing into a compact mass, and 
ease and cheapness of repair. 
The necessity of cheapness is of course the most important 
factor. But it must always be borne in mind that the cost of a 
road built of any given material includes not only the first cost 
but also the cost of keeping the road in good repair. The in¬ 
terest on the first cost of a durable but expensive material has to 
be compared with the extra annual cost of repairs where a less 
durable and cheaper stone is used. This necessity of cheapness 
forbids the transportation of large amounts of material for great 
distances except for the most important roads. Since the 
glacial drift and the various bedded rocks of the Silurian are 
the only available material in southern Wisconsin and in a large 
number of the other states of the Mississippi Valley, it is prob¬ 
able that in view of the recent increase of interest in good roads 
