37 
have been placed on twenty-eight of the larger or more interesting 
glacial boulders uncovered in the Garden during grading opera- 
tions. These tablets tell the lithological composition of the bould- 
ers and the fact that they were transported to the present site of 
the Garden by the continental ice sheet during the last glacial epoch. 
Their approximate place of origin is also noted, varying all the way 
from the southern border of the Adirondack Mountains to the 
northern end of Manhattan Island. For this data we are in- 
debted to the cooperation of Dr. Robert Balk, professor of geology 
at Hunter College, New York City. The tablets were the gift of 
Mr. Edward C. Blum, president of our Board of Trustees. They 
have been the center of widespread interest. 
On December 17, the Boys and Girls Club of the Garden pre- 
sented a most generous gift of $50 for the purpose of providing a 
large bronze tablet, to be affixed in 1933 to a glacial boulder at the 
base of Boulder Hill. On this tablet will be given the essential 
information concerning the geological origin and significance of 
the hill. 
School Service 
The statistics given in Table I, on page 38, are a quantitative 
expression of the nature and extent of our service to the public and 
private schools of Brooklyn. More extended statements are 
given in the appended reports of the curators of public and of 
elementary instruction. 
In addition to the supply of large quantities of study material to 
all grades of schools from Grade IIT A to the University, lectures 
and class instruction are given to visiting classes in the classrooms, 
plantations, and conservatories, covering 65 topics (29 scheduled 
and 36 additional by request of the schools) correlated with the 
course of study. These topics cover commercial geography and 
the plant life of the various countries, for Junior High Schools 
and grades below, as well as plant industry, nature study, and 
— 
botany. 
The visits of these classes serve primarily to enrich the puptl’s 
stock of information concerning plant life, to give concrete and 
definite mental images concerning material that would be quite 
inaccessible to most city children except for the Botanic Garden, 
to stimulate interest beyond what would be possible by merely 
— 
