GEOLOGICAL NOTES. 



BY D. F. H. WILKINS, B. A., BAC. APP. SCI., PRINCIPAL, HIGH 

 SCHOOL, BEAMSVILLE. 



Read before the Hamilton Association, 



Among the many interesting features of the rocks of Western 

 Ontario are some to which, it is believed, attention has not as yet 

 been directed One of these may be noted as occurring on and 

 near the Credit River, Streetsville, Peel County, Ontario, and as 

 presenting to us as nearly as possible the junction between the 

 Hudson River or Cincinnati Group, the highest member of the 

 Upper Cambrian or Lower Silurian of Murchison, and the Medina 

 Group, the lowest but one member of the true Silurian or Upper 

 Silurian of the famous geologist referred to. The flat, generally 

 clay country of Peel county slopes gradually south-westward to the 

 Credit River at Streetsville, and on the north-east bank of this 

 stream may be seen, below some six to ten feet of clay, a series of 

 greenish gray sandstones and argillo-arenaceous shales, some of the 

 former being sufficiently thick-bedded to afford good flagstones. 

 The series extends, as may indeed be clearly seen, under the river, 

 and has a thickness exposed on the bank of from eighty to ninety 

 feet. Moreover, from the more weathered shales and sandstones 

 may be procured the following fossils typical of the Hudson River 

 or Cincinnati Group; — Tetradium fibratum, Columnaria alveolata, 

 Favistella stellata, Favosites hemispherica, Petraia Canadensis, 

 Ambonychia radiata, Modiolopsis modiolaris, Avicula demissa, 

 Strophomena alternata, Orthis testudinaria, and more rarely, Orthis 

 occidentalis and fragments of an undetermined Orthceras. The 

 river here has a well defined trend, south, twenty degrees east, or 

 nearly so, and thus nearly conformable to the strike of the strata, 

 this latter being more accurately south, twenty-five degrees east, the 

 dip being, of course, south of west, at a very low angle. The flood- 

 plain of the river varies from a hundred feet to a hundred yards in 



