Professor Guijot on Physical Geography, 51 



were so numerous as in the same deposit nearer the head of the bay. 

 I had no means of ascertaining the elevation of this spot above 

 the lake, but it seemed to be more than 30 feet and the shells 

 bore evidence of great antiquity. 



The terraces before alluded to as bounding this flat are capped 

 with fine sand and their summits appeared to exceed 80 feet above 

 the level of the lake. They are well marked and extend for miles 

 along each shore of the Sound. At Peiett's Harbour, or the 

 French Village on the west side of Owen Sound and about twelve 

 miles from the town of the same name, two steep and very 

 well marked lake terraces rise, one above the other, near the 

 water's edge. They are both composed, as far as I examined 

 them, of shingle mixed with a little silt. The summit of the 

 upper one appeared to be about 100 feet above the lake and is in all 

 probability the continuation of the upper terrace running round 

 the head of the Sound, while the lower one corresponds to that 

 on which the town is built. 



When Lake Huron was at a sufficient elevation to form the 

 higher of these terraces, it was probably connected by a wide 

 expanse with Lake Erie, which is also proved to have stood at this 

 high level from the fact of a ridge holding fragments of decayed 

 wood and fresh water shells, running along its southern side at an 

 elevation of 150 feet above its present level. 



Montreal, Feb. Ath, 18QI. 



ARTICLE V. — Professor Guyot on the Physical Geography of 

 the Appalachian Mountain System. 



The great Appalachian backbone of Eastern America though 

 much visited in some of its peaks by tourists, penetrated by many 

 roads, and stretching through the midst of a civilised country, 

 has hitherto been little known to Physical Geographers in its 

 details. Prof. Guyot has made it a special subject of study since 

 his arrival in America; and since 1849 has devoted his summer 

 excursions to the accurate barometrical measurement of its eleva* 

 lions at various points throughout its whole length. The results, 

 including details of the methods of observation employed, and a 

 table of the heights of all the principal peaks, table-lands and 

 gaps, are published in Silliman's Journal ; from early sheets of 



