xx ;; memoir. 
ters of the whole group, but its geographical and 
geological relations, and many other generaliza- 
tions of much interest and importance. He car- 
ried the manuscript with him to Europe, intend- 
ing to have some of the unfinished plates exe- 
cuted there. This most valuable work was left 
so nearly complete that it may be regarded 
as essentially his work. 
His last and his greatest effort in behalf of 
science was, to carry into effect a purpose, long- 
since formed, of obtaining, through the liberality 
of the Boston public, a building for the Society 
of Natural History, which should amply accom- 
modate its present and prospective collections. 
In his anniversary Address, in 1846, he set forth 
in the most lucid and convincing manner, the 
wants of the Society, the absolute uselcssness of 
adding to its collections in consequence of a 
want of the means for their preservation and dis- 
play, and the claims which the objects and labors 
of the Society had upon the public. By a vote 
of the Society, this address was afterwards 
printed and circulated, as an appeal to an en- 
lightened and liberal public ; and it will ever 
stand as »an enduring memorial of his just 
appreciation of the claims of science, of his 
