PROCEEDINGS 
OF THE 
NATURAL SCIENCE ASSOCIATION 
OF STATEN 
ISLAND. 
VoL. VII. No. 6. 
APRIL 8th, 1899. 
The regular meeting of the Association 
was held at the residence ot Dr. Arthur 
Hollick, New Brighton. In the absence 
of the President Mr. J. B. Hillyer was 
elected chairman pro tem. 
The following paper by Mr. L. P. Grata- 
cap was read: 
1HE SIGNIFICANCE OF THE ACCUMULA- 
TION AND DISTRIBUTION OF BOWLD- 
ERS ON THE NORTH SHORE OF 
THE ISLAND. 
A surface survey and a mere ocular 
estimate seems to show tbat the trap 
bowlders, and indeed bowlders. of all 
sorts are numerically greater on the north 
shore of Staten Island than through its 
interior region or south ofits hills. The 
back and flanks of the morainal hillocks 
do not display so ncticeable a collection, 
nor anywhere is the sprinkling of la. ge 
masses of angular and transported rocks 
as striking. But on the northern side of 
the Island there is observable as well a 
local restriction, and were cue to actually 
count the distribution of bowlders, deter- 
mining their prevalence per acre, the ob- 
server would probably be forced to admit 
that from West New Brighton to Staple- 
ton, and from the north shore inland for 
about one mile, the bowlders attain their 
gieatest numerical density. While with 
still further concentration of attention 
the hillsides back of New Brighton, to 
West New Brighton and the adjoining 
shores, would become pre-eminent as the 
region where bowlders appear more 
thickly deposited. Building, railroad 
construction, fence making, etc., have 
greatly disarranged and diminished the 
impressions vividly leftin my mind many 
years ago, before the present era of 
metropolitan excitement and develop- 
ment began, but still the contrast to-day 
seems appreciable between this section 
and the areas east, west and south of it, 
as regards their respective bowlder popu- 
lations. Tiese bowlders are for the most 
part superficial, being on the surface, half 
imbedded in the underlying earth, or 
found ten to twenty feet below the surface. 
Taken in connection with the al- 
mitted lower level of the continent in 
glacial days they strongly impress tue 
observer as ice-raft or iceberg transported 
fragments. It is not difficult to imagine 
that during these long years when, with 
intermittent advances, the great ice sheet 
shruvk and receded northward, detached 
portions, laden with a rocky burden, 
floated from its crumbling edge and, car- 
ried southward, stranded on the half- 
emergent borders of our islet, then a post 
glacial shoal, shallow, or reef. The well 
established course of translation would 
have been down the valley of thie Hudson, 
or down the more western chaunels, 
formed in the Triassic trough, in the pres- 
ent valleys of the Passaic and Hackensack. 
The bergs or ice-rafts descending by the 
latter course would have been carried 
eastward through the preglacial channel 
of the Kill von*Kull, and here colliding 
with those descending tbe Hudson, all 
reaching Staten Island by either avenue, 
would have stranded on the protuberapt 
point of the Island, now represented by 
Stapleton on the east to West New Brigh- 
ton and Mariners’ Harbor on the west, 
and approximately over this arena the 
greater number of these erratics woud 
