Professor Ch. Fred. Ihtrtf., M. A. — Simonds. 73 
tween the tide-marks, atforded much material, plant and in- 
sect remains,* new to science, the discovery of which added 
not a little to the already increasing fame of the young geol- 
ogist. His account of this locality may be found in Dawson's 
Acadian Geology. f About this time (1863) occurred the 
most important event in his career, viz., the acceptance of an 
invitation from Louis Agassiz, the foremost living naturalist, 
to come to Cambridge as a special student in the great museum 
he had there established. For three years Hartt labored un- 
der the direction of that eminent teacher, spending his vaca- 
tions in the further investigation of the geology of Nova 
Scotia and New Brunswick. In 1864 he accepted a position 
on the Geological Survey of the latter province where, in con- 
junction with professor G. F. Matthew, he first recognized the 
Primordial group. 
In 1865 he was appointed by professor Agassiz, one of the 
geologists of the Thayer expedition,. and in that capacity ac- 
coi;:panied him to Brazil. On this and a subsequent private 
expedition in 1867, he accumulated the materials, which, when 
elaborated, were incorporated in a liandsome book of over six 
hundred pages entitled "Geology and Physical Geography of 
Brazil." published by Fields, Osgood & C'o., Boston, 1870. 
In the prefatory note of this work professor Hartt wrote: 
"This volume is the result of two journeys made by mj^self 
"in Brazil. The first was undertaken under the direction of 
"professor Agassiz in connection with the Tha^'^er expedition 
"in the years 1865 and 1866. On this journey I studied very 
"carefully the geology and physical geography of the coast 
"between Rio and Bahia, going over a very large part of the 
"ground on horseback or in a canoe. * * Mr. Copeland and 
"I made very large collections of marine invertebrates and 
'•fishes, though we did not neglect to secure otiier objects of 
"natural histor}^. I hope that these collections will throw 
"much light on the fresh water and marine animals of the 
"coast, and, as they were made at frequent intervals between 
"Bahia and Rio de Janeiro, that they will prove valuable in 
*For many years these Upper Devonian fossils wei-e retjarded as the 
carHest representatives of insect life in th(^ world, a few specimens only 
having been found, in Eui-ope, as low as th(> Carboniferous, but late 
discoveries, in southern Sweden, show that insect-life is there repre- 
i-ented as far back as the Lower Silurian. 
tSee Second Edition p. .'")1.'{ et se(|. 
