1 



■)0 



but undoubtedly other and better specimens of this mineral 

 may be found in other masses of the same rock. 



The locality is an interesting one and deserves to be more 

 fully explored. No doubt but that it will afford other good 

 specimens. 



Although our County is ancient and was early settled, yet 

 its natural history, especially in some of its departments, has 

 only begun to be developed. It is to be hoped that the Insti- 

 tute, among other objects, also devoted to this one, will be able 

 to finish the work it has auspiciously commenced. 



By request, Mr. Gilbert L. Streeter furnished the following 

 interesting and minute account of the discovery of the above 

 minerals : 



The locality in which the minerals occcurred, was a pit, or 

 quarry, a short distance below the Almshouse, upon the road 

 passing along the northern side of the Neck, towards Hospital 

 Point. This quarry was opened in the autumn of 1855, to 

 furnish materials for the new marginal road, by Collins' Cove. 

 I chanced to be there in October last, in company with Messrs 

 G. F. Chever and S. Johnson, jr. and when leaving the excava- 

 tion, noticed a block of compact sienile resting upon the bank, 

 the end of which presented a beautiful coloring of blue and 

 greenish white, with specks of black, which attracted our atten- 

 tion by its brilliancy in contrast with the prevailing hue of the 

 rock. Upon examination, these conspicuous minerals were seen 

 to be in a vein, a portion of which was connected with the 

 block of sienite. The mineral since called cancrinite was 

 distributed through the vein in small masses, which gave a 

 flecked, blotched, or clouded appearance to the rock. The color 

 was a rich azure blue, and the structure quartzose. It was 

 surrounded by, or rather mingled with, an abundant dull 

 greenish mineral, {daeolite^ in which were occasional plates 

 of black TTiica. We obtained some choice specimens of can- 

 crinite^ better, I think, than any afterwards found. 



On a subsequent visit we discovered the vein in place, in a 

 large mass of detached sienite disclosed to view beneath the 



ESSEX INST. PKOCEED. 20. 



