282 THE CANADIAN NATURALIST. [Vol. X. 



side of the Diindas valley, on the terrace, at 90 feet above the 

 vrater, on which the Dundas cemetery is situated. 



Whilst the Erie clays extend to a considerable height above 

 the lake on the borders of the marsh, they do not reach much 

 hio;her than the water level at Burliu2:tou Heights. This fact 

 has a bearing on the study of the Heights themselves. 



Between the Duudas valley and the Grand river (that is, in the 

 western part of the township of Ancaster and the adjacent por- 

 tions of Brant), the country is generally overlaid by a brownish 

 clay, often loamy, remarkably free from stones, and the equiva- 

 lent (on the surface) of the Saugcen clays Prof. Wilkins has 

 observed this "brown clay" in stratified beds along the Fair- 

 child's creek. 



The Forest bed of Ohio, represented in Canada by logs and 

 stumps, in the brown clays, at Toronto and elsewhere (Hind), 

 marks the period of elevation of land during which the Erie and 

 Leda clays were denuded before the deposition of the Saugeen 

 arenaceous clays and Saxicava sand (of the St. Lawrence valley). 



VIII. — STATEMENT OF THE PtLACIAL AND ICEBERG THEORIES. 



Before considering further the Post Pliocene deposits which 

 occur in the "reo-ion about the western end of Lake Ontario," 

 let us briefly examine the two theories that are given in explana- 

 tion of their origin. It is not my purpose to enter details except 

 those that bear on the explanation of the deposits in the region 

 of study. 



The Glacial Theory. — During the later Tertiary days the con- 

 tinent stood at least several hundred feet above its present alti- 

 tude, probably at the time of the advent of the " great ice age." 

 The two theories — the Glacial or Glacier, and the Iceberg or 

 Floating Ice — differ essentially in the earlier part of the epoch. 

 The former of these theories (or hypotheses) seeks to prove the 

 continuins; elevation of the continent after the close of the Plio- 

 cene epoch proper; that a great continental ice-sheet capped the 

 northern portion of America, and reached in some instances as far 

 of the 39th parallel of latitude; that the old rivers flowing 

 southward had a greater pitch than at present, and the waters 

 from the meltins: irlaciers running down the elevated old river 

 channels in a southerly direction (and also making new ones), 

 scooped out most of the basins now buried to a depth often seve- 

 ral hundred feet below their modern representatives, or the pre- 



