DEPOSITS AND ELEVATION. 



deposits which he identifies as kitchen-middeus at low levels 

 on the west side of the Head^ he indicates the clay (Mr. 

 Binney^s till) on the western cliff of the isthmus^ disappear- 

 ing under sand in which are seams of Mytilus edulis, beds 

 of which occur at intervals along the coast-section. 



In conclusion Mr. Bonney considers that^ " after the 

 limestone hills of the district had acquired their leading 

 forms by upheaval and marine denudation^ the whole dis- 

 trict was depressed; the summits of the low rocky islets 

 became covered with ice-fields, which in places descended 

 in glaciers into the sea. At this period there were oscil- 

 lations of level_, during which the two lower beds were sub- 

 ject to slight denudation. After the deposition of the upper 

 bed of clay, there must have been considerable denudation 

 from the action of the retreating sea. To this must have 

 succeeded a period of depression, during which the mussel- 

 beds were formed ; and then the whole was gradually up- 

 heaved above the level of the sea.^^ 



In his ' Excursions of a Naturalist/ 1867, Mr. Garner re- 

 fers to the existence some years ago of a great accumulation 

 of midden or refuse-heap on the west of the Head, but im- 

 plies that what he describes is not now to be seen. 



Special references to other details of these or some other 

 observations will be made in their places in the following 

 notes. 



I introduce my observations by a short description of 

 the more ancient rocky basis of the Head. 



Rudely outlined, this hill may be described as a great 

 oblong mass of mountain-limestone, lying, generally speak- 

 ing, east and west, the strata somewhat depressed along 

 the centre line in the same direction. On the north side 

 the tilted strata are cut down in alternate cliffs and talus- 

 hidden scars to the sea-level in magnificent and often almost 

 vertical precipices. On the south side a similar but less 



