. Bulletin of the Geological Society of America. Geology. 472 A. A. JULIEN—AMPHIBOLE SCHISTS OF MANHATTAN ISLAND In addition to these isolated projections of tongues of schist, there ob- tains a common gathering of thin layers in small groups, separated by a few feet or inches of gneiss, which looks like the result of shearing of a series of apophyses of a dike. Thus in the fine exposure of 3 layers of the hornblende schist on the bank of the East river from Sixty-fourth to Sixty-eighth street, one mass, 4 feet thick, in passing a few rods north- ward becomes split up into 8 or 9 thin sheets.
. Bulletin of the Geological Society of America. Geology. 472 A. A. JULIEN—AMPHIBOLE SCHISTS OF MANHATTAN ISLAND In addition to these isolated projections of tongues of schist, there ob- tains a common gathering of thin layers in small groups, separated by a few feet or inches of gneiss, which looks like the result of shearing of a series of apophyses of a dike. Thus in the fine exposure of 3 layers of the hornblende schist on the bank of the East river from Sixty-fourth to Sixty-eighth street, one mass, 4 feet thick, in passing a few rods north- ward becomes split up into 8 or 9 thin sheets. This grouping of several separate layers needs, however, to be distinguished from instances of cross-section of several sharp folds in a single layer (West One hundred and tenth Street group), where a more uniform thickness tends to Figure 7.—Emergence of Apophyses and Section of Sheets of biotitic Quartz-diorite Schist. Locality, Morningside avenue west, north of One hundred and tenth street. and also from mere alteration of certain bands in a thick layer of horn- blende schist into biotitic gneiss. The following are examples of such clusters of parallel layers in close approximation, those marked ^ being no longer accessible to examination: 4 layers at West Fifty-eighth street between Ninth and Tenth avenues (*); 4 to 11 layers at East Sixty-fourth street, on bank of East river ; 3 layers, 1 to oi feet thick, in the subway through Central park at West Seventy- ninth street; 4 layers at East Eighty-ninth street and Third avenue (*); 3 layers at East Ninety-sixth street between Fourth and Madison avenues (*) ; 9 layers at West One hundred and tenth street and Morningside avenue west; 9 la3'ers, at least, at West One hundred and seventeenth to One hundred and nineteenth street and the same avenue : 3 layers at West One Imndred and sixty-third street, on the Croton aqueduct; 10 layers at West One hundred and sixty-fifth street, on path above the Speed- way ; 5 layer
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