490 MR. P. F, KENDALL ON A SYSTEM OF [Aug. 1902, 
almost destitute of included stones. This distinction has not been 
noted in the area to the south, but Mr. Barrow found that in the 
Northern Cleveland area the Upper Boulder-Clay was of the same 
character; while the lower bed differed from that described by 
Mr. Fox-Strangways only in being of a dark chocolate-colour, 
varying at Whitby to reddish purple. The same divisions, similarly 
characterized, are mentioned in the Geological Survey Memoirs on 
Eskdale & Rosedale, and on the country between Whitby and Scar- 
borough, but in that on the country south of Scarborough no 
attempt at such a classification is made. 
At Flamborough Head and in Holderness, however, the two 
Boulder-Clays appear with their normal characteristics. I may here 
remark that a relatively stoneless Upper Boulder-Clay has been recog- 
nized by Hull, Mackintosh, and others in Lancashire and Cheshire ; 
but I am not convinced that the distinction is a constant and valid 
one. The Middle Sands and Gravels form a very unsatisfactory 
division; and while in some sections they appear to be entirely 
absent, in others there are several beds intercalated between successive 
sheets of Boulder-Clay (as, for example, in a boring at Stokesley). 
Regarding the relative altitudes which these subdivisions are 
said to attain upon the hills, there appears to be complete accord 
among the officers of the Geological Survey. Both Mr. Fox- 
Strangways and Mr. Barrow remark that the Lower Boulder-Clay is 
found at much greater altitudes than the Upper Clay, and that the 
‘Middle Sands and Gravels range still higher.’ 
Apart from the general statement that foreign stones are more 
abundant in the Lower than in the Upper Clay, little has been 
recorded regarding any differences between the erratics contained in 
the Boulder-Clays. However, information of value has been supplied 
respecting the boulders contained in the Lower Clay at Whitby. 
They include Carboniferous Limestone, Magnesian Limestone, 
Yoredale cherts and sandstones and Shap Granite, along with patches 
of Lower Liassicshale. These records are of great importance, as they 
enable us to say that at the time when the oldest Drift-deposits of 
the district were being accumulated, a transport of erratics from the 
westward or north-westward had already set in. My own notes 
record the following stones from the ‘ Middle Sands and Gravels’ 
in the same cliff :— . 
Jurassic and other sandstones, Magnesian Limestone, Carboniferous Lime- 
stone (not very abundant), basalt, greywacke sandstone and conglomerate 
(‘sparagmite’?), jasper, alum-shale (a large block), Gryphea incurva, and a ball 
of red Boulder-Clay. 
This assemblage is very similar to that in the Lower Clay. Taking 
the whole of the erratics in the district without particularizing 
the beds in which they have been found, the following groups may 
be recognized :— 
1. Sepimentary Rocks. 
‘Greywacke’ sandstones and conglomerates ; jasper-pebbles ; Carboni- 
ferous basement-conglomerate (Roman- Fell type); Carboniferous 
limestones, cherts, grits, and sandstone; Brockram (Permian); red 
