A Conspicuous Staten Island Bowlder Trail^ 



Arthur Hollick 



Anyone who is interested in the phenomena of former glaciai- 

 tion on Staten Island may observe a number of striking exam- 

 ples, well exposed at and in the vicinity of the new road which has 

 been excavated under the railroad, at what is generally known as 

 " Crooke's crossing," near Great Kill station. A section has 

 been cut in the moraine, and the excavated material has been used 

 for grading and filling in the adjacent depressions. Two prom- 

 inent constituents of this material, aside from the prevailing Tri- 

 assic red shale and sandstone, are red jasperoid limonite and dark 

 green serpentine rock. These vary in size from large bowlders to 

 cobblestones and gravel. The serpentine specimens usually pre- 

 sent the shapes and markings characteristic of glacial transported 

 rock fragments, but the limonite, by reason of its greater hard- 

 ness, has undergone relatively little abrasion. 



The direction of glacial movement across Staten Island was 

 from the northwest, and if a walk is taken from the Crooke's 

 crossing locality toward the northwest it will eventually lead to 

 the original common home of these rocks on Richmond Hill and 

 the region immediately beyond, as far as the border of the Fresh 

 Kills marshes. 



The particular feature of interest that may be noted on the way, 

 however, is the conspicuous bowlder trail marked by the red jas- 

 peroid limonite. This trail may be readily traced and followed 

 by noting the occasional bowlders in place and those which have 

 been incorporated in stone fences ; and by keeping these in sight 

 the observer will finally terminate his walk where the salt marshes 

 just south of New Springville are a bar to further progress in 

 that direction. Here are stone fences made up almost wholly of 



1 Presented at the meeting of the Association December 20, 1913. 



