400 LAMPLUGH : LARGER BOULDERS OF FLAMBOROUGH HEAD. 
In the appendix will be found detailed notes of some of the 
Flamborough Head boulders which deserve especial notice either 
because of their large size or peculiar composition, or because their 
petrological character has been investigated by Mr. Harker and is 
described in his notes. 
Hornsea. 
The following list was compiled in the cliffs of boulder-clay 
immediately north of Hornsea. This part of the coast is systemati- 
cally overhauled by the collectors of " road metal," who even dig 
out the harder boulders from the cliff-face ; and I suspect that the 
excessive number of sandstones and the lowered proportion of the 
basalts in this as compared with the Withernsea list, may be owing 
to the selective agency of the cartmen. 
Table 7.— 100 boulders in the cliff north of hornsea. 
Per cent. 
17 Carboniferous Limestone 
45 Sandstone and Grit ; probably mostly Carboniferous 
18 Chalk (including one block of Red Chalk) 
4 Jurassic Limestone and Septaria 
10 Fine-grained Basalt 
2 Coarse-grained Basalt 
2 Porphyritic Felstone 
2 Granite 
100 
In this, as in the Withernsea list, the chief difference from the 
proportions which obtain at Flamborough is in the Secondary rocks. 
With regard to these, chalk boulders are far more numerous than at 
Tunstall (Withernsea), but this chalk seems rarely to have been 
derived from the Yorkshire beds, the flints in it being usually black 
or pink, and not gray. 
The Septarian nodules are probably from the Kimeridge clay ; 
and other evidence of the extensive degradation of this formation 
is furnished by some of the gravels interstratified with the boulder 
clays in Holderness, in which flat fragments of the bituminous shale 
of the Upper Kimeridge are of frequent occurrence, often accompanied 
also by rolled fragments of Belemnites from the Speetou clay. 
