46 
Harbour. The Sound is bounded on the north chiefly by high 
steep ridges o£ granite which plunge sharply into the sea; on the 
west by the low sand hills of Middleton and other beaches, and b> 
high cliffs of granite; on the south by a precipitous line of granite, 
flanked by the coastal limestone ; and on the east by the ocean, 
with Michaelmas and Breaksea Islands dividing the entrance into 
three channels. 
Oyster Harbour has an extremely narrow entrance, but opens 
out to a width of about two miles. Most of it is very shallow, 
and at low tide, large areas of its bottom arc exposed. At its 
entrance, the opposing sides are strikingly different, that on the 
west being the end of the low Middleton Beach and sand-cliffs, 
known as Ifmu Point, and that on the east being a granite mass 
513 feet high, which rises rather abruptly from the water. The 
western shore of the harbour is either fringed with low-lying silted 
up ground or with cliffs composed of sedimentary rocks of little 
Height, which bear evidence of marine abrasion. Most of the 
eastern shore is only a few feet above sea level with low ridges in 
the near background. The King and Kalgan Rivers enter at the 
northern end. 
Fig- 39- 
From the western end of Princess Royal Harbour and stretch- 
ing at least as far as Torbay Inlet, there is a belt of low-lying 
