No. l.J MATTHEW — GEOLOGY OF NEW BRUNSWICK. 91 



The remarkable Miocine flora of this island has been studied by 

 Prof. Heer, who concludes that at this period, evergreen forests 

 must have extended to the pole. In Europe there are indications 

 of a gradual refrigeration of the globe throughout the time of the 

 Pliocene, but in Acadia, where this formation is wanting, we find 

 the earlier tertiaries succeeded by the Boulder-Clay, a formation 

 indicating climatic conditions of extreme vigour. As far south 

 as New Jersey this deposit is of purely glacial origin, according to 

 Prof. Dana and other New Endand j?;eolo2:ists, but in the Middle 

 and Southern States the evidence of ice-action is not so marked. 



Much attention has been given to the study of glacial pheno- 

 mena over large areas in America, but geologists are not yet 

 agreed as to the causes of some of them. Prof. J. S. Newberry, 

 in an able article read before the New York Lyceum of Natural 

 History,* contends for the former existence of a great continental 

 glacier over all the region included in the hydrographic basin of 

 the St. Lawrence and Red rivers. To this cause he ascribes the 

 excavation of the basins of the Great Lakes (except Lake Supe- 

 rior) skirting the Laurentian hills from the State of New York 

 to the valley of the McKenzie River in British America. He 

 conceives that toward the close of the glacial epoch a great fresh- 

 water sea filled the central part of the area, extending eastward 

 as far as the Adirondac mountains in the State of New York ; 

 and that it was bounded on the south by the water -shed between 

 the streams which flow to the lakes, and those which seek the 

 Mississippi, and northward by an extensive glacier resting upon 

 the Laurentide hills. He supposes that the Erie clays spread 

 over this area, were deposited in an immense lake during a lono- 

 period of slow subsidence. At a subsequent time, as the land 

 rose again and the waters of the lake gradually drained away, the 

 Orange sand and other surface deposits were produced by the 

 erosion of the clay beds, as difi'erent parts of the lacustrine area 

 were brought under the influence of the waves. 



The Orange sand of the Mississippi basin, however, appears to 

 have had a different origin, for Prof. E. Hilgard, who had made 

 extensive explorations in Louisiana and Texas, states that it was 

 swept down the valley of this river by powerful southerly currents. 



Both Sir W. E. Logan and Dr. Newberry assert the cotempo- 

 raueous origin of the Erie clay of the west and the Champlain (or 



* Published in The American Xatm-alist, June, 1870. 



