SCIENTIFIC SURVEY. 243 



About Rockport the details of its distribution are more interest- 

 ing. In general the shape of the formation may be seen in Fig. 36. 

 Just south of the village its width quadruples ; and in less than 

 two miles to the west it has thinned out entirely. It is an impor- 

 tant fact, as learned from this map, that the formation makes a 

 bend of a right angle, running westerly instead of northerly. An- 

 other interesting fact is illustrated by a small patch of quartz rock 

 on the east side of the harbor. It is triangular in shape, and not 

 more than half a dozen rods wide, but it has been elevated so as to 

 stand side by side with a newer rock— a mass of strata that has 

 been elevated vertically. Consequently there is what is called a 

 fault between the two rocks, and we can see here the smoothed 

 vertical surfaces of both rocks where they rubbed against each 

 other during this vertical motion. Another fault is also shown 

 upon both sides of the harbor in connection with the quartz, where 

 the argillo-micaceous schist is displaced. Here too it is the quartz 

 that appears to have been elevated. 



In the first case the course of the fault is N. 10° E. ; the quartz 

 rock dips 30° S. E., while the adjacent wrinkled slaty rock dips 

 20° N. 80° E. In the second example the dip of the two rocks is 

 equally variable, the former dipping 60° S. T0° E., and the latter 

 50° N. 20° W. It is probable that the cause of these dislocations 

 is to be found in the bending of the course of the formation west- 

 wardly. Perhaps its original course was more to the northward. 



The characters of this rock show finely south of Goose river, on 

 the road to Rockland. Adjacent to the river the quartz is very 

 thin bedded, and dips northerly about 12°. A few rods south the 

 massive hyaline quartz dips 40° northerly. This rock appears in 

 niimerous bosses among the houses and gardens in this part of the 

 village. The position a mile west of Rockport is similar to that 

 just noticed. 



The more slaty portion of the quartz is above the rest ; and 

 upon the north side of the harbor, it is more largely developed, 

 often a real silicious slate. Upon Fig. 36 it is distinguished from 

 the rest of the formation, and is somewhat disturbed by faults, 

 as already indicated. Many of the layers are calcareous, and 

 exceedingly contorted. In order from south-east to north-west 

 are the following dips : 40° N. 80° E., 55° S. E., 20° N. 10° E., 

 40° N. 10° W., and 18° easterly. As the distance passed over is 

 less than half a mile, thqse various dips indicate disturbances. Be- 



