186 THE CANADIAN NATURALIST. [Vol. vi. 



may be seen in all stages of formation on the neighbouring hill 

 sides. Their effect to a geological eye is to give to this beautiful 

 valley an unfinished aspect, as if the time elapsed since its eleva- 

 tion had not been sufficient to allow its slopes to attain to their 

 fully rounded contour. This appearance is no doubt due to the 

 enormous thickness of the deposit of Post-pliocene mud, to the 

 uneven surfaces of the underlying rock, and possibly also in part 

 to the earthquake shocks which have visited this region. 



At the mouth of the Murray Bay River, the Boulder-clay, 

 which rests directly on the striated rock surfj;ices, and which is a 

 true till, filled with the Laurentian stones and boulders of the 

 inland hills, though resting on Silurian limestone, is evidently 

 marine, since it contains shells of Lecla truncata ; and many of 

 the stones are coated with Bryozoa and Spirorhes. It is also ob- 

 servable that on the N.E. sides of the limestone ridges the boul- 

 ders are more numerous and larger. Above the Boulder-clay 

 may in some places be seen a stratified sandy clay, which further 

 up the river attains to a great thickness. It contains Saxicava 

 rugosa, TeUina Grcenlandica, and Tellina calcarea, as well as Leda 

 truncata. The most recent deposit is a sand or gravel, often of con- 

 siderable thickness, and in some of the beds of gravel the pebbles 

 are more completely rounded than those of the modern beach. 



I have already, in Section I, stated my reasons for believing 

 that the upper part of the valley of the Murray Bay River may 

 have been the bed of a glacier flowing down from the inland hills 

 toward the St. Lawrence. N.W. and S.E. ktrige attributable to 

 this glacier were seen at an elevation of 800 feet, and the marine 

 beds were traced up to almost the same height, above which, to a 

 heidit of about 1200 feet, loose boulders were observed and 

 glaciated rock surfaces, but no marine deposits. It is probable, 

 therefore, that at a time when the sea extended up to an elevation 

 of 800 feet, the higher part of the valley may have been filled 

 with land ice. Whether the bergs from this, drifting down to- 

 ward the St. Lawrence, produced the N.W. striation observed at 

 a lower level, or whether at a previous period, when the land was 

 higher, the ice extended farther down, may admit of doubt. 

 Certainly no land ice has extended to a lower level than about 

 800 feet, since the deposition of the marine boulder and Leda clay. 

 Very large boulders occur in this vicinity. One observed on 

 the beach on the east side of the Bay, is an oval mass of lime 

 felspar, thirty feet in circumference, lying like most other large 

 boulders in this region, with its longer axis to the N.E. 



