June 3, 1921] 



SCIENCE 



511 



associated with the scientific exploration of 

 the Adirondack Mountains, the most pictur- 

 esque part of the State of liTew York, the 

 great playground of the people of this and 

 other states. In 1893 Gushing, with James 

 F. Kemp and C. H. Smyth, Jr., entered this 

 difficult field for the purpose of intensive in- 

 vestigation of its geological structure. For 

 more than one generation it had been a com- 

 mon remark among intelligent people that the 

 Adirondacks were " the oldest rocks on earth," 

 but except in broadest features their structures 

 were not understood or the relations of their 

 mountain-making rock masses, one to another, 

 comprehended. Professor Kemp, conceiving 

 the importance of a systematic attack on this 

 resistant field where geological information 

 had lagged so far behind the rest of the state, 

 brought together this little trinity of workers 

 under the auspices of the state survey and 

 its joint activity continued for many years; 

 and though the attack eventually became a 

 desultory one by two of the three, Cushing's 

 part went on without interruption. He was a 

 fine geologist in a difficult field, keen, patient, 

 with the factors of his problem fully in hand ; 

 an excellent petrologist with a perfectly com- 

 petent understanding of the dynamics of the 

 Precambrian rocks. His grasp of the compli- 

 cated Precambrian history of l^Tew York and 

 the succession of events composing it finally 

 enabled him to tell the story in his " Geology 

 of the Northern Adirondacks." From the be- 

 ginning of his field work in New York Pro- 

 fessor Gushing showed that he was quite as 

 competent to carry on the work in the un- 

 altered sedimentary rocks, even in the in- 

 tensive way which present requirements de- 

 mand. He was a manly, frank, open-hearted 

 and devoted student of his science, who chal- 

 lenged respect for his work and engaged the 

 deep attachment of those who were admitted 

 to his friendship. 



John M. Glarke 



When Gushing began his work in the Adi- 

 rondack region in 1893 the pre-Gambrian 

 rocks, excepting the area in which Kemp was 

 working, had been studied only very locally 



or by the aid of antiquated methods which led 

 to quite erroneous conclusions. An assem- 

 blage of crystalline limestone, quartzites, 

 schists and gneisses was clearly of sediment- 

 ary origin, while certain massive rocks were 

 as clearly igneous. There were also extensive 

 areas of gneisses and schists of doubtful ori- 

 gin. To determine the origin of these rocks, 

 together with the structural and age relations 

 of the various formations, was the funda- 

 mental problem. Working at first in the 

 northeastern part of the region. Gushing had 

 to deal mainly with rocks that proved to be 

 igneous, and he was able to establish not only 

 their origin but also, to a large extent, their 

 time relations, and particularly that of the 

 very extensive anorthosites and syenites. The 

 work was later extended to the southern edge 

 of the Adirondacks and, finally, to the north- 

 western part, his last paper being a report on 

 the Gouverneur quadrangle, now in press. 



In this district he came in contact with ex- 

 tensive areas of the Grenville sedimentary 

 series, and worked out in detail their rela- 

 tions to the granites, syenites and gabbros. 

 In this work he emphasized the relatively 

 slight erosion of the crystalline rocks as com- 

 pared with districts to the east, with the re- 

 sultant partial, or complete, survival of the 

 roofs of batholiths. In the course of these 

 years of field and laboratory study he gath- 

 ered a great mass of data which afforded the 

 basis for important papers dealing with dif- 

 ferentiation, assimilation, and other petxologic 

 problems. In this work he was greatly aided 

 by a series of highly accurate analyses of 

 rocks made for him by his friend. Dr. E. W. 

 Morley. 



One can not look over Gushing's publica- 

 tions on the Adirondack region, even casually, 

 without being impressed by the great volume 

 of work represented, and the wide range of 

 problems treated. The more carefully his 

 papers are studied, the more evident is the 

 wealth of accurate observation and carefully 

 reasoned conclusions contained in them. They 

 constitute a brilliant record of achievement 

 in a difficult field of research. 



C. H. Smyth, Jr. 



