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Part II, which forms the bulk of the volume, begins with a chapter 
on the geological history of the state, followed by a detailed descrip- 
tion of the different quarry-areas. The igneous and metamorphic 
rocks are first enumerated and described, and the author clearly shows 
the variety as well as the architectural beauty and value of the granitic 
rocks of the state. The only metamorphic rock mentioned is quartzite. 
The sandstones are divided into three classes, partly on a geo- 
graphical and partly on a geological basis. The first class includes 
the northern Potsdam sandstone, comprising what is ordinarily known 
as the Lake Superior brownstone, which apparently differs quite 
markedly from the sandstones of the southern Potsdam area and the 
St. Peter’s formation included in the second and third classes. Neat 
sketch maps show the location of the quarries with reference to the 
markets and the transportation facilities. The limestone quarries are 
conveniently divided on a geological basis into (1) the Lower Mag- 
nesian, (2) the Trenton, and (3) the Niagara. 
Chap. vil relates to the areas from which suitable stone for dif- 
ferent uses may be obtained, such as building stone, bridge stone, 
paving blocks, etc. - It has a direct economic bearing that will no doubt 
be appreciated by architects, builders and dealers in stone. 
In the next chapter there is a discussion of the results of physical 
tests which are conveniently summarized at the end of the chapter ina 
series of thirteen tables. ‘The crushing strength may really have little 
significance to the scientist, but has great weight with the architect. 
In this respect the Wisconsin granites and limestones have shown sur- 
prising results. The excess of strength of the Wisconsin granite over 
that from other states is possibly not so great, however, as the tests 
might lead one to believe. Granting that Gilmore’s formula is incor- 
rect, it is not conclusive proof that a large cube is not stronger than a 
small one in a ratio greater than the comparative areas of the faces. It 
might have been better to have given the dimensions of the cubes of 
the granites tested from other states along with the figures quoted and 
permit the reader to draw his own conclusions. 
One of the most important sections of the report has to do with 
the effects of freezing and thawing on the strength of building stones. 
Numerous experiments have been made leading to the conclusion that 
freezing and thawing, continued for a considerable period, lessen the 
strength of rock, and that the loss in strength is in a general way pro- 
portional to the crushing strength of the rock. In other words, the 
