129 
side of Beach Island, near Sandy Deach, is а small exposure of 
a porphyrite (?) dike—N. 5? E., 4 feet, vertical—which is 
cut off by a fault. 
The Diabase Dikes. 
No attempt is made in the list of E.—W. dikes to distinguish 
or separate the first and second systems; but in both this and 
the N.—S. list the dikes are described in topographic order, 
g in each case at the western end of the Cohasset Rocks, 
° 
beginnin 
near Green Hill Beach and Forest Avenue. The data of the 
lists are sufficient for the identification of the individual dikes, 
if taken in order; but in the brief notes which follow the lists, 
some additional landmarks and bearings аге given. 
Hast- West Dikes. 
Width 
No. Trend. Hade. in Remarks. 
feet. 
88 N. 80? E. "or 3.5 Coarsely porphyritic; cuts 75, 
76, and 77. 
89 N. 80° Е. Vertical 6.5-7 Exposed about 750'; cuts 76, 
Tt, and 78. 
VO INIT 7 Ha NV. 0 25-30 Branches toward east end: cuts 
81; cut by 152-8-4. 
90a! N. 85° E. N, 97 2-3 A northern branch of 90. 
DT. М 809 E. Nd 1.5-2 A south. branch of 90; cuts 8I. 
92 E.-W. Vertical 2-3 Exposed over 300“; probably 
unites with 93. 
VB N. SOS Ii O 2-8 8' S. of 92; 92 and 98 cut 84. 
94 | N. 80? E. Vertical 9 Exposed about 300'; cuts 85 
апа 86; magnetic. 
95 N80 B. SV 8-8.5 60/ S. of 94; cut by 156. 
96 N. 80° E. Vert.-S. 59 | 8 75'S. of 95; parallel with flow- 
structure of granite. 
9T N. 607.20. N. 159-209 | 4-5 125’ S. of 96; cuts 87. 
98 N. 80° E. Vertical 1-2 50! S. of 97; irregular; cuts 87. 
99 | N. 659-70? E. | N. 20° 2-4 E. end Pleasant Beach; cut by 
100; irregular. 
100 | N. 80? E. Vertical b E. end Pleasant Beach; ex- 
posed long distance. 
LOL UNS TOT B, iN 1 150! S. of 100. 
102 N. 80? Е. S. 59-109 8—4 About 250! S. of 101. 
108 | N. 85° E 26! S. of 102; W. end of Sandy 
Beach ; irregular. 
104 | N. 759-80? E. | Vertical 3-4 N. side of Beach I.; probably 
cut by 105 and 107. 
105 | N. 85° E. Vertical 10 N. side of Beach I.; exposed 
long distance. 
OCCAS. PAPERS В. 8. N. H. IV. 9. 
