RECENT GEOLOGICAL WORK AT THE LIZARD. 115 
within a few yards in most intricate order. East of Caerleon 
Cove the foreshore was thickly strewn with boulders of serpentine 
and banded crystalline rocks, amongst which were many showing 
crystals of white or pink felspar in their dark hornblendic ground 
mass. The crystals varied in size, from 5x3 inches to some less 
than ^ inch long, and studded some boulders so thickly as to 
resemble mosaic. The parent rock was found in situ on the 
foreshore and running up the cliff, and was a diorite. 
East of Kennack Beach were two extensive exposures of granitic 
rock, conspicuous from a boat by a bright rust colour they gave to 
the cliffs. Among the schistose and ribboned gabbros, west of 
Spernic arch, were basic bands of porphyritic rocks. At Downas 
Cove, at the north-east end of Kennack Bay, basic dykes, and 
fine and coarse gabbros were found, with a granulitic gabbro 
composed of felspar and colourless pyroxene. Throughout the 
region between Kennack and Downas Cove, a light greenish-grey 
serpentine at times traversed the dark red serpentine in the 
manner of dykes, and contained crystals of picotite. These were 
seen best at Lankidden Cove, and at Butter Cove, a little west 
of Downas Cove. In the latter exposure the dyke was more 
disintegrated and jointed out of the cliff, and each crystal of the 
resinous-looking picotite was surrounded by a border of lighter 
colour than the main mass. 
The junctions at Coverack were numerous and interesting, and 
the olivine-gabbros exported thence for metalling roads, made 
splendid sections for the microscope. After passing the uralitic 
gabbros of the Manacle rocks, and the hornblendic gneiss of the 
Drawna rock district, the trip was supposed to end at Porthallow, 
where the junction of the slates and schists was so disorderd, 
and covered with so much debris, as to give rise to much difference 
of opinion amongst geologists, both as to their origin and actual 
mode of occurrence. 
The lecturer dwelt on the changes constantly occurring on the 
coast from falling cliffs, and on the difficulty experienced in 
examining some foreshore sections from the mass of sand, shingle, 
and seaweed, at times thrown up by the sea. 
The various theories of the leading geologists were then 
referred to at length. 
Seventy years ago Professor Sedgwick, as the result of a careful 
survey of the district, wrote: "We were led to conclude that 
