A CONTRIBUTION TO THE GEOLOGY OF SOUTHERN MAINE 547 



Table X. 



Analysis of Dunose from near Bayville, Maine. 



Composition. 



Molecular 

 Proportions. 



Norm. 



Si0 2 





37-4i% 



.623 



Or 



2.22 



A1 2 3 





2.18 



.022 



Ab 



4.19 



Fe 2 3 





3-64 



.023 



Cor 



1.02 



FeO 





3-46 



.048 



Hyp 



!-54 



MgO 





41.08 



I.027 



01 



72.32 



CaO 





none 





Mg 



.02 



Na 2 





•54 



.008 



Cmr 



•3 2 



K 2 





.41 



.004 



11 



•3° 



H 2 + 





8.84 









H 2 0- 





.09 









co 2 





2.03 









Ti0 2 





.12 



.002 







P 2 5 





.08 









Cr 2 O s 



tal 



.16 



.001 







Tc 



100.04 





THE DIABASE DIKES. 



Diabase dikes are well known on the coast of Maine. To the 

 list of localities already reported should be added at least six 

 dikes from the Boothbay quadrangle. The fiord character of 

 the coast makes it impossible to determine whether one dike or 

 several are present when the trend is such that they cross the 

 bays, but wherever the alignment coincided we assumed one 

 dike whatever the variation in width. The topography how- 

 ever is very suggestive of faulting and it is recognized that the 

 alignment may be accidental in some cases. For this reason 

 a series of microscopic slides was made and studied, of every 

 exposure. The distribution of the dikes is shown on the map. 

 The dikes described by Dr. Bascom from 1 the eastern part 

 of the quadrangle are inserted on the map (Fig. 2.). 



It will be observed that there are four dikes having a direction 

 of N. 85 E. These dikes are all large, varying in width from 

 thirty to one hundred and fifty feet. The southernmost one 

 outcrops on the coast of Southport Island near Cape Newagen ; 



1 " Dikes from the Vicinity of John's Bay, Maine," Am. Geol., XXIII, 

 1899, p. 275. 



