86 REVIEWS 
Maryland Geological Survey, Vol. III, Baltimore. The Johns 
Hopkins Press, 1899. 
This volume consists of the application of geology to the ‘per- 
manent and economical improvement” of the roads of Maryland. It 
consists of 461 pages and 80 pages on ‘‘ Laws of Maryland relating to 
highways.” There are 35 plates, including 14 maps, and 38 figures. 
The state geologist, Professor William Bullock Clark, contributes 
the Preface, Part I, Introduction, and Part II, ‘‘The Relations of 
Maryland Topography, Climate and Geology to Highway Construc- 
tion.”’ The author discusses the ‘‘ dependence of the highways upon the 
surface configuration of the land,” and their dependence upon the 
underlying formations; the effects produced upon the roads by tem- 
perature changes, precipitation and winds. He gives the areal distri- 
bution of the various geological formations of the state, accompanied 
by amap, and with a hint to roadmasters to make use of the information. 
Then follows a discussion of the road materials of the state and their 
relative values for road building. 
Part III, “ Highway Legislation in Maryland, and its Influence on 
the Economic Development of the State,” is contributed by St. George 
Leakin Sioussat. 
Part IV, “The Present Condition of Maryland Highways,” and 
Part V, ‘“‘Construction and Repair of Roads,” are by Arthur Newhall 
Johnson. 
The condition revealed in Part IV amply justifies the Survey in its 
undertaking to direct attention to the need and the methods of 
improvement. Yet Maryland has some excellent highways, and the 
average condition of its roads is perhaps as good asin most of the states. 
On the other hand Massachusetts and Connecticut are states which 
are noted for their good roads. In Part V Mr. Johnson gives practical 
instruction on grading, drainage, and surfacing which will be of great 
service in road-building, 
The following Parts, VI, VII, VIII, are by Harry Fielding Reid. 
Part VI treats of the “‘ Qualities of Good Road-Metals and the Method 
of Testing them.” In this chapter Professor Reid deals with the fol- 
lowing series of laboratory tests of materials, viz., microscopic test ; 
abrasion test; crushing test; cementation test. The results of these 
tests upon various rocks are illustrated. Part VIII, relative to ‘‘ The 
Advantages of Good Roads,” is adapted to awaken an interest in road 
improvement. 
