24] 
the last Ice Age. The southward-moving ice picked up and car- 
ried along innumerable boulders derived from rock ledges in vari- 
ous localities north of what is now Long Island. During their 
journey, these boulders were rounded and polished and, in some 
cases, marked with striations that still persist. Twenty-eight of 
these boulders have had their lithological composition carefully 
determined and compared with that of rock ledges to the north. 
By this study it has been possible to determine, with a fair degree 
of accuracy, the approximate places from which the boulders now 
in the Botanic Garden were derived. Bronze tablets, given by 
President Edward C. Blum, of the Board of Trustees, have been 
placed on these boulders, telling their composition and probable 
place of origin, and stating that they were brought to the Garden 
by the continental ice-sheet during the glacial period. 
A similar bronze tablet is mounted on a boulder at the foot of 
3oulder Hill (which takes its name from the large glacial erratic 
on its summit). The inscription reads, “ Boulder Hill and the en- 
tire northern portion of the Botanic Garden are part of the terminal 
glacial moraine extending from The Narrows to Montauk Point. 
This tablet was given in 1932 by the Boys’ and Girls’ Club of the 
3rooklyn Botanic Garden.” 
Guide No. 7, The story of our boulders, has been prepared for 
the uses of classes in geography or geology, or others who may be 
interested, and may be obtained at the Information Desk and [tn- 
trance Gates. Arrangements may be made in advance for docents 
1ese labelled boulders. 
— 
to conduct classes who wish to study tl 
