— | 
TRANSACTIONS OF SECTION C. 797 
about, first, through chemical changes in the different substances of which the 
coal was composed ; secondly, the different forms which the coal has assumed in 
the geological changes that have taken place since; and it follows that we must 
look as much or more to the geological features as to the chemical ones for a 
right judgment as to the uses to be made of them for coking, gas-making, and 
for use in different kinds of fire-ranges and furnaces. 
4. On the Boulders and Gilaciated Rock-surfaces of the Yorkshire Coast. 
By G. W. Lamptucn, F.G.S. 
An enumeration and analysis of the larger boulders (those over one foot in 
diameter) which strew the cliffs and beaches of the Yorkshire coast have yielded 
interesting results bearing on the direction and character of the ice-flow. 
Comparisons of the lists compiled at various widely-separated localities reveal 
points of agreement, and of difference, which are equally suggestive. 
The following condensed table shows the chief features of these boulder-lists :— 
Eel saul 
n Ss] _ «9 
peo lege l2.o | Bsia.g| as | Bs 
ze O83 |aea. AER és a S.4 
Bee | Bae lmoes| oaks lease | 2s [eee 
Boulders over 1 foot in diameter. Aad | S64 |. @us|/ aon |, 2s rales apb.4 
Origi Om SHH |2458|/ haf) 644] oF | Suez 
rigin. Bee | mas |ese=| seo | S38) $8 | ees 
2 | a8 |2sea| ee | bss = |Bas 
Bea | 5228 |3°8"| 82/52) 22 | 8 
Eee | ean rs eave) ae che Ae 
QR eo\a S ca Ss S aS Ss 
| r=) mn al a 
| per per per per per per per 
| cent. | cent. cent. cent. cent. | cent. cent. 
Carboniferous Limestone (in- | 22°8 JAE? | BIS 13° Het ewileee }) “Bip 
cluding also a few other 
Palaeozoic Sedimentary Rocks) 
Sandstones, Grit, Conglomerate, | 14:4 45° | 26°8 15- 25 28 18 
&e. (probably all, or nearly all, 
from Carboniferous or other 
Palzozoic Rocks) 
Mesozoic Rocks (Jurassic Lime- | 22:1 22: 1: 51: 40: 48- | 35:5 | 
stones and Sandstones, Chalk, 
&¢.) 
Basaltic and other Eruptive | 37:3 14° | 43°2 19: 18: 7 |e1b5 
Rocks 
Granite, Schist, Gneiss, &c. . 34 ZEON R34 7p ett 4: gloat 
| | | 
Total . : : . | 100° | 100: | 100: | 100: | 100° | 100- | 100: | 
Nores oN THE Lists. 
Although there is usually some difference in the distribution of the various 
rocks at ditferent horizons, these lists may be taken as indicating the relative pro- 
portion of the different rocks among the larger boulders contained in the whole 
mass of the drift. In two localities, however, where it was necessary to examine 
the boulders lying on the beach, it is probable that the proportion of the basaltic 
rocks has been unduly increased, and that of the sandstones diminished, through 
the differentiating action of beach-erosion. 
In every case the proportion of boulders from the Carboniferous system is high, 
ranging from about 25 per cent. to as much as 60 per cent., or even more if the 
basalts, which must often have come from the same formation, be reckoned in, 
} This paper formed the fourth of a series published in Proc. Yorks. Geol 
and Polytech, Soc. for 1887-9 and 1890. 
