The American journal of science and arts . at irregularity common in dikes,an observer might almost hesitate to record facts that may add tothe obscurity of the subject, were it not, that valuable generaltruths can be derived only from an extensive comparison of in-dividual facts. Dikes in Moultonhoro\ Two trap dikes, in sienitic granite, are found on the right of theroad on the top of Rogers hill, one and a half miles from Moul-tonboro corners, towards Tamworth ; course W. by N.; parallel,and both contain fragments of granite of considerable size. Fig. 4. No. 1; one foot wide ; sends off a la
The American journal of science and arts . at irregularity common in dikes,an observer might almost hesitate to record facts that may add tothe obscurity of the subject, were it not, that valuable generaltruths can be derived only from an extensive comparison of in-dividual facts. Dikes in Moultonhoro\ Two trap dikes, in sienitic granite, are found on the right of theroad on the top of Rogers hill, one and a half miles from Moul-tonboro corners, towards Tamworth ; course W. by N.; parallel,and both contain fragments of granite of considerable size. Fig. 4. No. 1; one foot wide ; sends off a lateral branch which curvessoutherly; eight inches wide. No. 2; three feet from the former, is two feet wide, and por-phyritic, with crystals of feldspar. - Dikes in Tamworth. At Fort Jackson, in Tamworth, about four miles west of Thingstavern, on the right of the road at top of a hill, fifty rods fromBear Camp river, is a small trap dike in granite, six inches wide;course E. and W. Mineralogy and Geology of the White Moimtains. 113 Fig. No. 2, one quarter of a mile east of the former, crosses the bedof Bear Camp river at right angles; course N. by E. ; one to twofeet wide; inclines down stream at an angle of 40° or 50°, andcurves up stream like a bow; is itself crossed in the middle of thestream by a narrow granite fault or vein ; on the lower side inseveral places, the granite, from its greater softness has been re-moved by the water and the dike, being left prominent, presentsthe appearance of a dam. This exposes, on the side of the dike,a series of longitudinal light and dark gray stripes, never over twoinches wide, arranged horizontally in regular alternations.* Theriver bed above, as well as below this dike, is filled with trap ruins. Dikes in Eaton. On the hill, near Mr. Eleazar Snails, one quarter of a mile eastof the village, are two dikes from two to three feet wide andthree feet apart; course in general N. E. by E. ,* one containing a * I owe this notice to the k
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