. Guide leaflet. in thepier walls the ledges have been cut incross section and are supported by ad-jacent ledges. In the bulkhead walls theledges have been cut on a bevel and appearas sharply pointed long rock slivers,having wide tops and thin lower edgeswhich, in walls 46 feet high, may remainunsupported for distances of 60 to 75feet. This slivered appearance of the schistin the bulkhead walls has come aboutthrough drilHng the rock face in a north-east direction (N. 29° E.),and cutting theledges at an angle of 15 degrees. Further-more, the drill has gonevertically downward andcut across succe
. Guide leaflet. in thepier walls the ledges have been cut incross section and are supported by ad-jacent ledges. In the bulkhead walls theledges have been cut on a bevel and appearas sharply pointed long rock slivers,having wide tops and thin lower edgeswhich, in walls 46 feet high, may remainunsupported for distances of 60 to 75feet. This slivered appearance of the schistin the bulkhead walls has come aboutthrough drilHng the rock face in a north-east direction (N. 29° E.),and cutting theledges at an angle of 15 degrees. Further-more, the drill has gonevertically downward andcut across successiveledges pitched steeplytoward the river; con-sequently, in the upperpart of these newly madewalls the ledges were cut,and wedge-shaped masses BULKHEAD WALL OF 1890 Resting on bags of concrete,laid by divers on glaciatedsurface of granite pegmatite,Pier 90, foot of W. 50th Street,New York, N. Y. Photo-graph supplied by Allen and Son, contractors By Eric J. Baker, Elizabeth. 174 NATURAL HISTORY. Courtesy Cunard Line By Airmap Corporation of America, N. Y. S. S. BERENGARIA DOCKING AT PIER 54, NORTH RIVER, NEW YORKLarge transatlantic liners require numerous tug boats to warp them into position alongside the pier of rock were left lianging on their schistosesurfaces without sufficient basal support toinsure a stable wall. The V-shaped outlineof these attenuated hanging ledges is shownin cross section in accompanying photo-graphs taken by the author, and in thediagrammatic representation of the struc-tural features in slips 2 and 3. These structural features, togetherwith the presence of numerous inter-secting joint planes, have caused slidesto occur in some places along the bulk-head walls. In the northeast corner ofslip 2 a large slide occurred April 28,1933, which was some 75 feet in lengthand extended from Stations 800 to part of the wall which slid out waswedge-shaped in cross section, wide at thetop with dimensions 15 to 25 feet inwidth, about 30 fee
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnatural, bookyear1901
