340 THE JOURNAL OF GEOLOGY. 



reports of the Arkansas Survey, this volume does not confine the dis- 

 cussion of the subject to Arkansas alone, but treats it also as a general 

 proposition, thereby adding greatly to the usefulness of the report. 



The general synopsis of the volume, given above, defines its scope. 

 The marbles and other limestones of Arkansas are very properly dis- 

 cussed more in detail than any others, but a general description of 

 these materials in other parts of the United States, as well as in the 

 more important foreign localities, is also given. The author has not 

 only given his own experience and investigations in the subject in 

 Arkansas and other regions, but has collected in a systematic manner 

 a large amount of useful information published elsewhere. He dis- 

 cusses also very fully the geology and chemistry of marble and lime- 

 stones in general, as well as their various uses for ornamental and 

 structural purposes, for making cement, burnt lime, etc. The discus- 

 sion of the best methods of working and utilizing marbles and lime- 

 stones, together with the plates illustrating these processes, will be of 

 much use to the people of Arkansas, as well as elsewhere, in devel- 

 oping industries of this kind. The volume is really to be considered 

 a text-book on marbles and other limestones, and not a report on the 

 occurrence of these materials in Arkansas alone, though the treatment 

 of the subject as related to that state is of course given prominence. 



One of the most remarkable points brought out in the volume is 

 the immense amount of marble contained in the state. In a belt of 

 country lying north of the Boston Mountains and extending from near 

 the Black River on the east to beyond Eureka Springs on the west, a dis- 

 tance of more than 125 miles, the marble is continuous, and the length 

 of its winding outcrops as mapped is 2,812 miles. The combined area 

 of the six maps necessary to represent this marble region is 4,450 square 

 miles. This area extends east and west along the north slope of the 

 Boston Mountains, on both sides of the White River and its tributaries, 

 which run southeasterly in a general direction parallel with the moun- 

 tains. The rocks are approximately horizontal, or dip gently to the 

 south, and the marbles, which occur in both Silurian and Lower Car- 

 boniferous horizons, are exposed where they have been cut through by 

 the creeks and rivers. The marbles vary greatly in quality and color, 

 but many of them have been proved by practical tests made under the 

 direction of the Geological Survey, to be of great strength and excel- 

 lent quality. In color they vary from white to gray, pink, red, brown, 

 and black, the gray, pink, red, and brown colors being the most com- 



