TJie Geology of H Ingham. 33 



less, east of these dike exposures occur considerable bodies of trap, 

 but the connection with them is not perceptible. 



On Leavitt Street, about a mile and a half from Leavitt's Bridge 

 going east, and less than a quarter of a mile before reaching the 

 town line, a trap dike crosses the road diagonally. It appears 

 first on the right side for a few feet, and the exposure on the left 

 is seventy-five feet from where the first is lost to view. In neither 

 place does it show above the surface more than a few feet, nor can 

 it be traced beyond the two exposures. Its width is about six feet, 

 and it is porphyritic. Its direction is east and west. 



Lasell Street. ■ — Considerable elevations of granite skirt Lasell 

 Street on the left side, some of which approach and border the high- 

 way. After passing Free Street 740 feet, one of these is reached, 

 which presents a bold front, having a very interesting dike of about 

 six feet in width. Lichens obscure this somewhat, on the face of 

 the rock as seen from the street, and one needs to climb to the 

 upper surface to study it to advantage. Here it is found extending 

 itself a considerable distance east, showing, away from its margins, 

 a porphyritic character, the crystals of feldspar being quite distinct. 

 Fifty feet south of this is another dike, parallel with the first, but 

 having a width of only thirty-two inches. This does not exhibit 

 crystals of feldspar so perceptibly, its cooling having been too 

 rapid for their favorable development. This dike cannot be seen 

 from the street, as the front face of the rock has retreated from 

 its border. The two dikes have both an east and west direction 

 by compass, as have nearly all that are found in the granite not 

 approximate to the rocks of the sedimentary series. 



Long Bridge Lane. — At the granite quarry of Mr. Israel 

 Whitcomb, about a quarter of a mile from Union Street, may be 

 seen two dikes east and west by compass, one about a foot wide, 

 the other twenty-two inches. They are not far from thirty feet 

 apart. 



Friend Street. — On the right-hand side of this street, pro- 

 ceeding from Main, and not far from the latter, may be seen two 

 dikes cutting through the granite of the roadway, both having a 

 general direction of east and west, and both of which may be 

 traced for considerable distances. The first is found 330 feet 

 from Main Street, and varies from four to six feet in width. This 

 may be observed in the adjoining field, 80 to 100 feet east from 

 the road, and has been traced west across meadow land in differ- 

 ent ledges, nearly 1,000 feet. The second one is about forty feet 

 beyond the first-mentioned, and has a width of about two feet. It 

 appears on both sides of the carriage way in the bordering ledge 

 through which the street was cut, but is not so readily seen on the 

 left as on the right without close observation. This has been 

 traced 120 feet or more. 



Union Street. — There is a dike on this street, 360 feet from 

 Lasell Street going east, which may be seen in a ridge of granite 



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