. Guide leaflet. Reeds, N. HANGING MASS OF GRANITE PEGMATITEShowing bulkhead wall, slip No. 3, foot of West 51st Street,New York City. The rock is steeply inclined and jointed 172 NATURAL HISTORY. ROCK SLIDE, BULKHEAD WALL, 49th street, N. hanging wedge-shaped mass of Manhattan schist, 75 feet long, slidinto the 46-foot-deep excavation on April 28, 1933. Photographsupplied by Allen N. Spooner and Son, contractors not do this unless it is reinforced. The granite pegmatites, which areigneous in origin, are abundant in thepier walls, but they do not represent themajor po
. Guide leaflet. Reeds, N. HANGING MASS OF GRANITE PEGMATITEShowing bulkhead wall, slip No. 3, foot of West 51st Street,New York City. The rock is steeply inclined and jointed 172 NATURAL HISTORY. ROCK SLIDE, BULKHEAD WALL, 49th street, N. hanging wedge-shaped mass of Manhattan schist, 75 feet long, slidinto the 46-foot-deep excavation on April 28, 1933. Photographsupplied by Allen N. Spooner and Son, contractors not do this unless it is reinforced. The granite pegmatites, which areigneous in origin, are abundant in thepier walls, but they do not represent themajor portion of the rock mass. Theyappear in the form of large and small dikes,sills, stringers, veins, and lenses cuttingand penetrating the schist. Some of thedikes are from six inches to four feetacross, others twelve to one hundredfifty feet in width. The more prominentof these features have been sketcheddiagrammatically in the accompanyingisometric drawing of the pier and bulk-head walls. The granite pegmatites invaded theManhattan schist as molten masses of rock and cooled slowlyin the positions they nowoccupy. In some placesthe mineral ingredientsare typical of a coarse-grained pinkish granitewith the grains of
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectnatural, bookyear1901
