14 TRANSACTIONS OF THE [OCT. 11, 



following observed iHps and strikes from various portions of the 

 area will indicate the truth of this statement : 



Near corner of Westervelt avenue and Second avenue. New 

 Brighton, Str. N. 45 E.. Dip 70 NW. ; summit of the north- 

 west side of Pavilion Hill. Str. N. 45 E., Dip 70-85 NW.; 

 eastern side of Pavilion Hill, 900 feet west of the granite out- 

 crops on the shore, Str. N. 45 E., Dip 70 NW". to nearly vertical; 

 here the rock is delicately crumpleii ; west of Garretson's 

 Station, Str. N. (JO E., Dip 20-80 SE. and much contorted, ap- 

 parently lying in several gentle folds ; west of Grant Citv, Str. 

 N. 60 E., Dip 55-70 NW.; Ravine near Egbertville, Str.'N. 75 

 E., Dii)85SE. ; on Meissner avenue, near Richmond, Srr. N. 

 80 E., Dip. 80 N.; one-fourth mile northwest of this outcrop, 

 strike and dip same; in vallev of brook one mile north of Eg- 

 bertville, Str. N. 50 E., Dip. 40-50 XW. 



3. All the serpentine areas of Southeastern New York and vi- 

 cinity, such as those of Staten Island, Hohoken, West 59th 

 street and vicinity, New York Island, New Rociielle arid Rye, 

 AVestchester County, lie in the same general line of strike and 

 appear to occupy a well-defined belt in the surrounding gneisses 

 and schists. These outcrops may, imleed, be but portions of 

 the same strata alternately buried by the |)itcli of the folds and 

 again brought to the surface by faults of vertical throw; this 

 structure lias been conclusively demonstrated in the highlands 

 of New Jersey, ami may well apply to the rocks now under con- 

 sideration. The crystalline limestone areas of New York Island 

 and Westchester County lie parallel, cr nearly so, with this 

 serpentine belt, as may be seen on the excellent map published 

 by Professor Dana in the American Journal of Science, vol. XX. 

 These limestone outcrops are of the same general shape as those 

 of the serpentine and its associated minerals, and their detached 

 occurrence is probably due to the pitch and fault structure 

 above noted. Crystalline limestone occurs in and with the ser- 

 pentines at the West 59th street area and at New Rocheile; at 

 West 59th street, parts of the rock are indistinguishable from 

 parts of the Staten Island material, and here is found in great 

 abundance the" hydrous anthophyllite,^' which is very much like 

 some specimens from the deep well on Staten Island. Many of 

 the crystalline limestones contain tremolite, and in some of them 

 this mineral is extremely abundant ; specimens obtained by Mr. 

 Kemp from near King's Bridge are at least one-half tremolite. 

 It is not alone in pure masses, but is scattered through the rock 

 in fine crystals, and at Pleasantville, Westchester County, forms 

 *' mountain leather." The serpentine of Staten Island contains 

 much amianthus, doubtless the altered state of tremolite, and 

 3Ir. B. B. Chamberlin has found this matted into a substance 



