40 J. PKESTWICH ON THE QUATERNARY PHENOMENA 



Southwell this is overlain by another bed, due rather to rain- wash 

 (see fig. 7, p. 39). 



At Lulworth and Arish Bay, a local angular drift-deposit of the 

 some age flanks either side of the valley facing the sea. 



Other Drift Beds. 



The wide undulating tract of the Kimmeridge and Oxford Clays, 

 Coral Rag, and Forest Marble between Portland and the Chalk range 

 is generally perfectly bare. It is only at the following places that 

 I have met with other small beds of drift : — 



1. At levels of from 30 to 50 feet on the skirts of the hill between 

 Portland Perry and Wyke. It is a coarse gravel, composed of sub- 

 angular Chalk-flints and Greensand chert* with a few pebbles of Port- 

 land flint, from 2 to 4 feet thick, and reposing upon a worn and eroded 

 surface of Kimmeridge Clay and Coral "Rag (&", see Map and Sect. 

 PI. I.). 



2. Between Melcombe Regis and Furzeland are two low flat hills 

 about 50 and 60 feet high, capped by a peculiar drift-gravel, which 

 is worked on the left of the road turning off to East Chickerel. It 

 consists almost entirely of subangular fragments of chert from the 

 Upper Greensand, imbedded in a red clayey matrix, from 2 to 8 feet 

 thick, sometimes covered with 2 feet of grey clay, and reposing in 

 patches upon a very irregular bed of Oxford Clay. It was only after 

 some search that I found in it a few small subangular chalk flints 

 and a small pebble of white quartz. A similar gravel caps the hill 

 half a mile west of the bridge over the Back-water (c, PL I.). 



3. Traces of a coarse gravel-drift, chiefly of chert, exist on the 

 top of Crook Hill, near West Chickerel ; but there is no bed of it. 



4. On a hill between Weymouth and Broadway, east of Badipole, 

 and at a height of about 70 feet, is a thin bed of gravel, composed 

 of subangular chalk- and Portland flints, Greensand chert, large 

 Sarsen-stones, and Tertiary flint-pebbles (c). 



5. A similar gravel caps one of the hills midway between West 

 Chickerel and Portisham. 



6. A remnant of a much thicker deposit of gravel exists on the 

 cliff immediately east of Osmington Mill, and again east of Eadcliff 

 Point, at the higher level of about 150 feet. It consists almost 

 entirely of a mass of brown subangular chalk-flints, many of them 

 of large size, with a few fragments of Greensand chert, sandstone, and 

 Portland flint, in red clay and sand, 8 feet thick (6'). 



7. On a still higher level of about 300 feet, and capping the hill 

 on the right hand of the road between Preston and Osmington, a 

 small patch of fine flint and loess drift lies in hollows on the Portland 

 Stone (6). 



8. Another thick bed of still older gravel, composed chiefly of 

 local Tertiary materials, overlies, and is scarcely separable from, the 

 Tertiary beds at places on the highest points of the Chalk range f . 



* On one fragment was a cast of Pccten quadricostatus. 



t As I am uncertain of the extent of this bed, I have marked it on the map 

 in one shade with the Tertiary beds, which also consist chiefly of sands and 

 shingle-beds. 



