68 



J. A. Dresser — Study in the Metamorjihic Hocks 



Trenton in the vicinity of Richmond* forms the subject of 

 this paper. The line of the section extends between lots ten 

 and twenty-seven in the twelfth range of the township of Cleve- 

 land, and is about a mile and a half east of the St. Francis 

 river, to which it is approximately parallel. The direction of 

 the sections is 1ST. 38° W., magnetic. The adjacent rocks at 

 both north and south have been recently mapped in the reports 

 of the Geological Survey as Cambrian, the black limestone, 

 No. 3 of the section, as Trenton, and the rest as Precambrian. 



/* -J* . ' \ r&i ]// f ¥*■ fr* f- ■ ■ -1 



• \° / flf'F JBf i,/ \ M Preaai,ihrcau \-'- ':'■ 1 



7f-7 wf ) ( """'■'" ^ 



■ t . J y^T* , ^% y41 «'/ / =) 10 miles 



Sketch map showing the Precambrian of a portion of Southeastern Quebec 

 as designated on the Geological Survey maps of 1886 and 1894. 



1. Black Mica Schist 1 00 feet 



2. Gray Mica Schist 1320 " 



3. Black Limestone 2800 " 



4. Gray Mica Schist 4590 " 



5. Micaceous Dolomite 300 " 



6. Black Mica Schist 600 " 



7. Quartzite 180 " 



8. Micaceous Dolomite 60 " 



9. Gray Mica Schist 7360 " 



Total Sedimentary. ._ 17310 feet 



10. Amygdaloidal Trap ) l254Q « 



Total Igneous f 



* This locality was considered by Logan to furnish the key to the structure 

 of the Quebec Group. Hither he returned after severing his connection with 

 the Geological Survey, and spent four seasons in making a detailed map of 

 the disti-ict for about five miles on either side of this section. This map, 

 which seems to have been ready for engraving at the time of his death, was 

 unfortunately, never published. 



