82 The American Geologist. August, i897 
tance. Few of these finds proved little more than a stimulus 
fur further search. 
Dr. Jackson was a fairly good naturalist of the old school. 
Neither zoologist nor botanist, he was an observer of animals 
and plants in life, to say nothing of his stewing and cooking 
thsm in his beakers and condensers after they were dead for the 
sake of the information they would then afford. Witness his 
observations upon the bream, the ale-wife, the sand-sharks of 
Nantucket, the Spongilla in the Brookline reservoir, the pink 
water-lily, the studies of the habits of the beaver, and the 
notes on the giant Sequoias of the Sierras. But he was par- 
ticularly acute in the detection of mineial mattei, largely be- 
cause he was forever anal\^zing. He found traces of manga- 
nese in the waters of the middle of lake Su))erior; he found 
fluorine in the bony scales of certain fishes ; and before th« dis- 
coveries of Berzelius, although he did not name it, he detected 
humic acid in the soils of Rhode Island. Sooietimes his dis- 
coveries were of more than scientific interest, as was that of 
emery just described in the still worked mines of Chester, 
Mass, 
Almost disdaining to trust to fossils in the correlation of 
the stratified rocks, particularly where metamorphism was 
present, he was a constant collector of fossil fiishes and other 
forms met with in his field work. He even described several 
species of Palseoniscus. Some of the Deep River fossils des- 
cribed by Ebenezer Emmons, in his North Carolina report 
were collected by Jackson. 
Jackson's scientific life for over a quarter of a century fol- 
lowing the period of his active duties as a state geologist, is 
an integral part of the history of the Boston Society of Nat- 
ural History, and the records of this institution afford a val- 
uable commentary on his ready information in various depart- 
ments of natural science. Elected vice-president of the society 
in 1847, and declining on account of impaired health to be 
made president in 1870, he was a faithful attendant on the 
meetings of this organization during this long period; and 
was quite as often in the president's chair, as was the duly 
elected officer to that post. Here Jackson brought the dis- 
coveries of his field and laboratory'- work and the ripened con- 
clusions of his earlier geological inquiries, finding among his 
