RAISED BEACHES. 417 



It is also very instructive to note that these diluvial beds 

 mainly rest on the low crest of the narrow neck of land which 

 unites the bold headland of Pendennis with the mainland : and 

 that on other parts of our coast line where the same geographical 

 features exist the same geological beds are found. Notably, at 

 Cape Cornwall, where diluvial beds are found on each side of the 

 narrow isthmus which unites it with the main land. At the 

 "Island" north of St. Ives, where the narrow strait is choked 

 with diluvial gravel capped by large detached masses of angular 

 blocks of greenstone bedded in yellow loam. At the Towan 

 Head, Newquay, and at Trevose Head, where the drift beds on the 

 isthmus contain a more than ordinary quantity of angular flints 

 and flakes. All these beds throw a vivid light on the deposits 

 known as " Eaised-beaches," and tend to confirm their diluvial 

 origin. 



I have said that the Falmouth "Eaised-beach" is of a typical 

 character, to illustrate which I describe a section of the " Eaised- 

 beach " exposed in the face of the cliff on the south side of Spit 

 Point, Tywardreath Bay. The beds are described in their 

 descending order. 



1. Soil of brown loam passing down into sandy yellow 

 loam, with some rounded and angular pieces of quartz, all 

 pitched upright in the loam. About 6 feet. 



2. Beds of fine siliceous sand, with minute angular pieces 

 of slate-rock, with horizontal layers of small quartz pebbles. 

 About 3 feet. 



3. Fine gray sand, with small pieces of quartz, and a few 

 chalk flints. 18 inches. 



4. A bed of boulders and of pebbles perfectly water- worn ; 

 with others of elvan and granite, and angular pieces of clay- 

 slate, and also a few chalk flints. 15 inches. 



5. A bed of fine arenaceous sand, with angular bits of slate, 

 and semi-rounded pieces of quartz. 6 inches. 



The whole resting on coarse yellow clay-slate. The base of 

 No. 4 being about the level of high-water spring tides. 



About a quarter of a mile westward of the above section, 

 the same beds are exposed in the cliff, but the base of the ' ' Raised- 



