265 
The completion of the large circular compass and sundial, as 
the central motif of the Laboratory Plaza, awaits available funds 
which we hope may be contributed in the near future. The 
amount required is approximately $1,000. 
Labelled Boulders—The Brooklyn Botanic Garden is located 
near the western end of the terminal moraine of Long Island. 
This moraine was deposited at the southern edge of the continental 
glacier that occupied the northern part of North America, during 
the last Ice Age. The southward-moving ice picked up and car- 
ried along innumerable boulders derived from rock ledges in var- 
ious 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 by the ice. Bronze tablets, 
given by Mr. Edward C. Blum, have been placed on these boulders, 
giving their composition and stating that they were brought to the 
Garden by the ice-sheet during the glacial period. Guide No. 7, 
The story of our boulders, has been prepared for the use of classes 
in geography or geology, or others who may be interested, and may 
be obtained at the Information Desk and Entrance Gates. Ar- 
rangements may be made in advance for docents to conduct classes 
who wish to study these labelled boulders. 
