452 Haivkins — Notes on the Geology of Rhode Island. 



Norms of the Basic Igneous Bocks Analysed (Table II), 





1 



2 



3 



4 



5 



6 



7 



q 







5-79 











Or 



•56 



4-24 



12-58 



13-74 



10-29 



2-30 



9-97 



Ab 



3-67 



19-45 



25-82 



18-32 



20-35 



24-90 



7-94 



An 



5-56 



34-39 



30-81 



18-01 



29-50 



32-93 



33-25 



Di 





20-91 







16-24 





6-68 



Hy 



Ens 







13-28 









17-64 



01 



. 45-70 



8-09 





19-76 



13-23 



15-50 



914 



Mt 



. 20-65 





2-65 



5-24 



7-38 



1-86 



314 



11 



. 1900 



7-75 



3-80 





1-71 



9-50 



6-26 



Pr 



115 







2-55 









Ap 



Ak 





'i-50 



2-02 



21-76 









Cor .... 







3-25 











Gar .... 













11-50 





Spinel . . 

 Calcite .. 



3-55 



' ' -67 





"•62 



'i-30 



l-5i 



'5*98 



Classification of the Basic Igneous BocTcs Analyzed (Table II). 



1. Peridotite, rhodose, V.3.1.2. Iron Mine Hill, Cumberland.* C. H. 

 Warren. 



2. Gabbro, auvergnose, III. 5. 4.3. Ironstone Eeservoir, Mass.t A. C. 

 Hawkins. 



3. Gabbro (Hybrid), shoshonose, II.5.3.3. Woonsocket, E. I. A. C. 

 Hawkins. 



4. Gabbro, oronose-auvergnose, III.5.4.2. Pascoag v E. I. A. C. Hawkins. 



5. Gabbro (Actinolite Schist), auvergnose, III.5.4.3. West Greenville, 

 E. I. A. C. Hawkins. 



6. Gabbro, near auvergnose, III.5.4.5. Moosup Valley, E. I. A. C. 

 Hawkins. 



7. Olivine Diabase, oronose-auvergnose, III. 5.4.2. Snake Den, E. I. A. 

 C. Hawkins. 



8. Diabase, South Attleboro, Mass. Chemist, Am. Steel and Wire Co. 



9. Minette, Conanicut Island, E. I. J. P. Iddings. 

 10. Minette, Sakonnet Point, E. I. A. C. Hawkins. 



The last four rocks were probably not fresh. 

 * Compare Emerson (op. cit., 183 and 185). 

 t Compare Emerson (idem, 170). 



(2). The Diabases. 



The development of diabases is strongest toward the 

 northern border of the State; western Rhode Island is 

 free from them. They show a tendency to follow prom- 

 inent joint-planes which mark lines of structural weak- 

 ness, arranged in several zones with a north-sonth or 

 northeast-southwest strike. One of these appears to be 

 along the western margin of the Carboniferous basin at 

 Woonsocket and southward, while another lies a few 

 miles to the eastward, and still another extends south- 

 ward from Cumberland Hill. Most of these diabases, 

 both dikes and sills, are not very large, the most exten- 

 sive ones sometimes attaining a length of a quarter of a 



