B. A. Daly — Secondary Origin of Certain Granites. 199 



The diagrammatic map of fig. -± generalizes the field rela- 

 tions as expressed in Bayley's maps. There have been omitted 

 from the diagram certain complexities in the maps showing 

 the actual geology. The essential features are thus made all 

 the more evident ; at the same time it is believed that this 

 arbitrary treatment of the maps does not introduce error in 

 principles. 



A summary of the mineralogical compositions of the gab- 

 bro. intermediate rock, granite-keratophyre (granophyre) and 

 invaded sediments is given in Table I. The correlative dif- 

 ferences in chemical constitution are noted in Table IV. 



Table IV. 



Selected Analyses, Bayley on Pigeon Pt. 



A. B. C. D. E. F. 



Si0 o 49-88$ 57*98 72*42 73-85 59*71 70*31 



Titf„ 1*19 1-75 *40 -05 tr. tr. 



A1 2 3 1S-55 13-58 13-04 1091 18-32 12*81 



Fe" o 3 2-06 3-11 '68 6'98 811 7"26 



Feb 8-37 8-68 2'49 "89 '85 "88 



MnO -09 -13 -09 



CaO 9-72 2-01 "66 "44 1-05 "60 



BaO -02 -04 -15 



MgO 5-77 2-87 '58 1*52 3'54 2*03 



K„0 -68 3-44 4-97 1*39 3'43 1*90 



Na a O .... 2-59 3 56 3-44 2*28 1*93 2*19 



H„0 1-04 2-47 121 1-88 3*24 2-22 



P'O -16 '29 -20 



10012 99 91 100-33 100-19 100-18 100*20 



Sp. gr. .- 2-923- circa 2*620 not given, not 



2*9-70 2*740 prob. ca given, 



2*70 prob. 

 ca2*75 



A. Olivine diabase ; aver, of five specimens, .p. 37 



B. Intermediate rock ...._ 63 



C. Red granite ; aver, of 7 specimens 56 



D. Unaltered quartzites ; aver, comp 90 



E. Unaltered slate _ 90 



F. Approximation to aver. comp. of sediments 113 



The general similarity in the character and spatial arrange- 

 ment of the rocks at Pigeon Point and on the Movie River is 

 apparent. The comparison of conditions is obscure only as 

 relates to the structural cross-section. The Movie intrusive is 

 unquestionably a sill. The underground relations of the 

 Pigeon Point intrusive, for lack of decisive field evidence, 

 have not been fixed beyond the possibility of doubt. Bayley 

 savs : 



