J IDI OIRIA IL, 
In the death of Professor James D. Dana, American geology 
loses its most eminent representative. With due recognition of 
the preéminence of others in their chosen lines, no one has 
stood before the scientific world for the last three decades so 
widely recognized as the foremost general geologist of our 
hemisphere as Professor Dana. The period of his activity has 
stretched over a full half century. From the time of the publi- 
cation of his great work on the results of the Wilkes Exploring 
Expedition, his eminent ability has been recognized, and the 
appearance of his manuals of geology and mineralogy, which 
soon followed this, gave him a position of unequaled influence 
among the teachers and students of those sciences in this country. 
Upon these works his reputation chiefly rests. Owing to the 
delicacy of his health his field work was limited, and subsequent 
to the Wilkes Expedition, which gave him so comprehensive a 
familiarity with the great features of the earth, his personal field 
investigations were chiefly confined to the region adjacent to his 
home. His main work was that of compilation, interpretation 
and organization, and in this delicate field he showed great 
judgment and discretion. As we hope to publish a full and 
appropriate memoir at an early date, and as we give in this 
number a sketch of his characteristics as a teacher, prepared by 
an admiring pupil, it would be unfitting here to attempt a full 
analysis of his conspicuous services or his abilities. He pre- 
served his activity to the end of his life, fourscore years and ten 
and two, ina remarkable degree. The revision of his Manual 
of Geology, but just issued from the press, is a conspicuous 
illustration of this. But his activity did not rest even here, as it 
might very fittingly have done after so arduous a task. In a 
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