GEOGRAPHY OF NORTH AMERICA. 231 



sections, throughout the bituminous coal-field and oil re- 

 gion, will leave nothing to be desired there in the perma- 

 nent stratigraphical definition and classification of the coal 

 measures of the state. A new and brilliant liodit has thus 

 been thrown upon the geology of coal. Another year's work 

 will give nearly all that is needed on the subject of glaci- 

 ation. Nothing whatever has vet been done in the anthra- 

 cite field. The materials for it, accumulated by the railroad 

 and coal companies, are beyond calculation, and only need 

 collation and publication to make such a survey complete. 



Thirteen octavo volumes of the survey have been printed 

 and distributed, two more will shortly be published, and 

 three others are going through the press. Two volumes 

 are ready for the press and will soon be in hand ; and ten 

 volumes will be prepared this winter for printing in the 

 spring of 1878. With the exception of three volumes of 

 chemical analyses, one of oil-well records, one of railway 

 and other levels, and one by Professor Lesquereux on the 

 flora of the coal, these thirty volumes form a library of 

 local county geological reports. Exhaustive indexes, geo- 

 logically arranged, give them, however, a scientific value. 

 The county maps published with them will be followed by 

 a small pocket atlas of colored geological county maps of 

 the state. 



The only object of the present survey is to put the geolo- 

 gy of Pennsylvania within reach of every citizen of the state. 

 If geologists find new knowledge in its publications, it is 

 clear gain ; for they are not written for geologists, but for 

 the common people of Pennsylvania. Accuracy and com- 

 pleteness are the only desiderata kept in view\ 



The Geological and Natural-history Survey of Minnesota, 

 though small in proportion to the preceding, possesses an 

 independence of political influences and a stability which 

 make it particularly worthy of our attention. It has just 

 completed its sixth year, and is established on a secure 

 though small financial basis, being under the supervision of, 

 and making its reports to, the regents of the state univer- 

 sity. It seems destined to do a good work for the state, 

 so mr as geology and the kindred sciences are concerned; 

 but the only basis for its topography appears to be the de- 

 termination of the latitude and longitude of certain points 



