Geological Society. 143 
analyst, for example, will be disposed to think the tables which he 
most frequently requires too limited; while he may be disposed to 
think that tables of the values of Hebrew, Greek, and Roman 
measures, of the number of vibrations per second which constitute 
FZ or Dp, of Geological formations, or of Tide-tables, are (to him) 
useless matter. In view of the small size of the present (first) 
edition, we trust that in a second edition many of the tables may 
be extended. For example, it would be most useful to have, 
instead of the present page of 4-figure logarithms, a table of 
5-figure logarithms ; the table of trigonometrical ratios might with 
great advantage be enlarged; and the same remarks apply to the 
tables of boiling-points, the table for the conversion of tempe- 
ratures, and the table of lengths of rivers. We would further 
suggest that in the table of rotation of polarized light the effect 
of temperature should be taken into account; and that the compa- 
rison of electromotive forces for various batteries should be sup- 
plemented by some statement of their usual internal resistances. 
A little more explanation might occasionally be given; e. g. in the 
first table, at present, stands the statement that when n = 2, 
3 = 950,000, which of course is not intended. Still these are small 
matters which can easily be set right in a second edition, which will 
no doubt soon be required. 
XVIII. Proceedings of Learned Societies. 
GEOLOGICAL SOCIETY. 
[Continued from p. 64. | 
December 14, 1884.—W. Carruthers, Esq., F.R.S., Vice-President, 
in the Chair. 
ae following communications were read :—- 
1. “On the South-western Extension of the Clifton Fault.” 
By Prof. C. Lloyd Morgan, F.G.S., Assoc. R.S.M. 
This fault cuts across the strata out of which the Avon gorge has 
been excavated, a little north of the Suspension Bridge. According 
to the author’s estimate the throw of the fault is, on the Gloucester- 
shire bank, somewhat less than 1200 feet, and somewhat more than 
1100 feet on the Somersetshire bank. The difference of nearly 100 feet 
the author considered to be, in part at least, due to the dying-out of 
the fault to the west. Taking as a datum-point the intersection of 
the line of fault and the line of high-water mark, the rocks relatively 
shifted downwards are, on the Gloucestershire bank, Mountain 
Limestone 730 feet, Upper Limestone Shales 470 feet. © According 
to this estimate there would be 130 feet of Upper Limestone Shales 
