188 
i st LM CET 
ріне Uh. 
Fic. 18.— PLAN SHOWING THE INTERSECTION OF TWO 
DIKES ON THE EAST SIDE OF BEACH ISLAND. 
SCALE, 1 INCH — 8 FEET. 
crystals. It outcrops west of the hotel, east of the hotel, and 
then, after some faulting and branching, on the east side of 
Strawberry Point. The remaining dikes on Strawberry Point 
(131—142) are easily found and identified by taking the ledges 
in order from west to east, one of them (135) cropping on three 
distinct ledges. 
North-South Dikes. 
Width 
No. Trend. Hade. in Remarks. 
feet. 
149 | Nos WA Vertical 3-4 On Cohasset Rocks, 400! E. of 
| Black Rock ITouse. 
In the valley immediately E. 
149% N.-8. Vertical | of the Black Rock House; 
imperfectly exposed. 
150 N. 50-10 E. | Vertical 2-3 On Cohasset Rocks; cuts 80 
| obliquely. 
151 | N.-S. Vertical 8-4 Interrupted and faulted; cuts 
90. 
152 | N.-S Vertical 8-6 Cuts 90; irregular. 
158 | N.-S Vertical 6-7 Cuts 90; unites with 152. 
154 | N.-S. Vertical 7.5 Cuts 90; branching northward. 
105 CN: 8 Үү, Vertical 8-8.5 About 200! E. of 154, on Cohas- 
set Rocks. 
156 N. 59-109 E. | Vertical 2 On Cohasset Rocks; cuts 94 
and 95. 
157 | N. 159-459 E. |S. E. 800-45 2-8 On Hominy Point, near White 
Head. 
On the short, stony beach immediately east of the Black Rock 
House thereare traces of several — at least three and possibly 
more—dikes (149a) of this system, recalling the composite dike 
of the Nantasket area (66). The last of the north-south dikes 
