No. 384.] /AMES HALL AND AMERICAN GEOLOGY. 899 
the schists, slates, and marbles of the green hills of Vermont 
as altered silurian sediments, and it has been the great distinc- 
tion of the present Director of the United States Survey to 
prove this. 
The same investigator has also vindicated the term “ Hudson 
River” as embracing the section from the Trenton to the over- 
lying Upper Silurian rocks, enclosing the Utica, a term instituted 
by the New York geologists, and more narrowly defined by 
Hall, though at first somewhat resisted by him. 
Certainly to the far wider audience of scientific readers Hall 
stands as the embodiment of paleontological prestige. The 
enormous publications of the New York Survey, their later 
resplendent illustration, and the numerous dissertations and 
contributory essays on genera, families, morphology, and distri- 
bution of fossils, found in the Reports of the New York State 
Cabinet, have fixed the eye of attention upon Hall as a zoologist. 
In no real sense was Hall a zoologist. His actual acquaintance 
with animal life was slight, and his system and habit of arrange- 
ment entirely mimetic. Certainly an enthusiastic and contem- 
plative mind could hardly have escaped distinction in bringing 
to light the rising series of fossil forms which the regular 
succession of rocks displayed. Hall handled the retinue of 
forms thus presented with signal success. His work at first 
was tentative, but became increasingly valuable, especially as 
the influence of two great works educated his perception, 
and the influence of more acute zoologists, employed as his 
assistants, directed his discernment. 
The formative influences of the Canadian Survey and 
Barrande’s Système Silurien are plainly discernible in the pro- 
gressive improvement of the Paleontology of New York. The 
Canadian Survey, with which for a short time he was con- 
nected, brought him into contact with a new field of fossil 
exploration, and he felt the stimulation of Sir William Logan 
as a helpful factor in his studies. The preparation of the 
decades and his close analysis of the: graptolitic fauna were 
distinct advances over his former work in paleontology, wherein 
also it can hardly be denied that the extraordinary morpho- 
logical instinct of Whitfield played a beneficial part. And in 
