366 Geology of 



CHAPTER XIV. 



(A) Eaised Beaches. 



Befoee proceeding to treat of the Great Glacier Period of New 

 Zealand, I consider it convenient to speak first of two other formations, 

 partly deposited before this important era in the geological history of 

 this Island began. The first of these formations consists of a deposit 

 of marine shells, raised about 100 feet above the sea level, near the 

 mouth of the Motanau river, situated in the northern portion of the 

 East Coast. This bed, which I was not able to trace to the south, 

 contains, according to Professor Hutton's researches, only recent 

 shells, with the sole exception of Mactra rudis. It is thus of post 

 pliocene (or quartemary) age, but I am unable to say if the deposit in 

 question is of pre-glacier age, no moraioic or alluvial deposits, formed 

 during the Great Glacier period being found in its proximity. One 

 fact, however, is certain, namely, that the land in post pliocene times 

 in the northern portion of the province along the east coast stood at 

 a lower level than at the central and southern portions. Thus, whilst 

 the raised beach near Motanau rises about 100 feet above the sea 

 level, gradually getting lower and disappearing near the mouth of 

 the Waipara altogether, in all the more southern portions of the 

 coast, where the country has not been subjected to nuviatile action, 

 only beds of loess or silt are met with near the sea level. They either 

 cover the hill sides for several hundred feet or form downs of large 

 extent. 



