1 8 HISTORY OF COH ASSET. 



appears to have only a beggar's portion of the hornblende 

 or mica, and the crystals are very fine. These veins of 

 number three granite are sometimes as thin as a knife 

 blade and never larger than a few feet. There are some 

 outcrops exposed by blasting at the roadside of Beech- 

 wood Street near to the lane which leads to Turtle Island. 



Another exposure is on Atlantic Avenue near the 

 Lothrop House ; while there are many veins of it to be 

 seen in the rock along the edge of the sea. 



While this third granite has never come to the daylight 

 except through narrow fissures, the outer granite has been 

 very much worn off so that only patches of it here and 

 there are to be seen. Some of it is in the ledge at the 

 head of Depot Court, and above it in Deacon Bourne's 

 Rock. There is one ledge that is perhaps the most pictur- 

 esque in town, composed of this first granite. It is called 

 Rattlesnake Den, a frightfully shattered crag of rock thirty 

 feet high and one hundred feet broad, lying in the deep 

 woods half a mile west of Lily Pond. 



All along our north shore at the water side of Jerusalem 

 Road this dark-colored, finely crystalline granite prevails ; 

 and it is along this exposure of rock that the flow struc- 

 ture spoken of above is repeatedly to be seen. 



These three kinds of granite grade into each other, and 

 some pieces are not plainly differentiated. Outside of 

 them all was a coating or scum of rock that cannot be 

 called granite because it lacks the quartz. Its main con- 

 stituent is feldspar, but not the same kind as makes the 

 beautiful milky crystals in the granite, being oligoclase in- 

 stead of orthoclase. 



The name of this rock is diorite, and its color is a dark, 

 dirty green. Streaks and strings of feldspar are snarled 

 around in its dark mass. Not very much of it has been 

 left on top of the granite, for the eiosion of millions of 

 years has nearly banished it from Cohassct. 



Just east of Kimball's Hotel there is a knob of it washed 



