Mesozoic and Cenozoic Geology and Paleontology. 197 
beach, 12 feet ; Ist drift terrace, 29 feet; 2d drift terrace, 46 feet ; 
3d drift terrace, 75 feet ; summit of plateau, 94 feet. 
The rocks in many places are grooved, scratched and _ polished. 
These phenomena, of course, can be seen only where the drift deposits 
are absent. The groovings consist generally of parallel furrows, from 
one to four lines wide—sometimes extending a foot, at others many 
yards. Where the rock is very hard, they are mere striz. Hollow 
“spots occur, as if they had been scooped out by a round instrument 
and also wide bowl-shaped depressions, known as troughs, which have 
been caused by the same agency. Grooves and scratches were ob- 
served on the road from Eagle river to the Cliff mines running N. 15° 
E. On an island east of Dead river there are two systems of strize— 
one running N. and S8., and the other N. 20° E. and 8. 20° W. The 
rock here which is very hard and tough hornblende, is not only grooved 
and furrowed over its whole extent, but there are, beside, deep trough- 
like depressions, with perfectly smoothed walls, some 12 to 15 feet long, 
4 feet wide, and 24 feet deep. On Middle Island, east of Granite 
point, troughs may also be seen 4 feet wide, and 2 feet deep, running 
like the strie N. 20° E. On the promontories and islands near Wor- 
cester, two miles west of the mouth of Carp river, there are two distinct 
sets of strise ; those running N. 55° E. are the most numerous ; thuse 
running N. 5° E. the least. The latter cross the former and are there- 
fore more recent. Some of them are, beside, distinctly curved, as if 
the body which produced them had been deflected in ascending the 
slope. Each set of striz extends only about one foot below the water’s 
edge. On the first quartz ridge, one mile from the mouth of Carp 
river 500 feet high, the strie run N. 20° E. On the iron ridge south 
of Teal lake, 750 feet high, the strizs run N. 55° E, At the Jackson 
forge N. 65° E. A green magnesian rock, with vertical walls, and semi- 
cylindrical form, on the road leading from Jackson landing to Teal lake 
is covered with strize which may be traced along the surface, like hoops 
around a gigantic cask. On Isle Royal the strie run N. 50° E. with 
many local deviations. On the shores of Ackley bay strize near the 
water’s edge running E. and W., cross others running N. E. and S. W., 
and others again running 8, 75° E. Isle Royale presents but little 
evidence of drift, though scattered bowlders are found upon it; the 
surface of the rock s are generally, however, smoothed, as if polished 
off. 
Mr. E. Desor described the superficial deposits on the northern 
shore of Lake Michigan, the western shore of Green bay, the Big Bay 
