Prof. Sedgwick on Trap Dykes in Yorkshire and Durham. 211 
In the table of cubes. 
Nos. 11 for 1338 read 1331 
408 — 67911312 — 67917312 
702 — 345948008 — 345948408 
813 — 537366797 — 537367797 
The last 3 errors apply also to Dr.Hutton’s Course and Tracts. 
In Dr. Gregory’s Mathematics for Practical Men: 
Table II. of Supplementary Tables. 
In the column of Areas. 
Nos. 7 for 38. 6000 read 38. 1001 
18 — 264. 46900493 — 254. 46900494 
19 — 6 — 9 
24 — 07 — 12 
28 — 7 — 18) 
33 — 89 — 94 
40 — 4143 — 6144 
56 — 68 — 41 
61 — 922 — 00 
64. — o—_— 8 
65 — 10k 5 
96 — o_ 7 
In the areas for Nos. 22, 27, 30, 32, 39, 45, 48, 51, 54, 57, 
60, 62, 66, 69, 72, 75, 87, 90, 99, increase the last figure by 2. 
In Nos. 1, 8, 9, 10, 14, 16, 20, 21, 23, 26, 29, 34, 36, 38, 41, 
42, 44, 46, 47, 49, 50, 52, 55, 58, 59, 63, 68, 70, 71, 74, 78, 
81, 84, 85, 86, 88, 89, 92, 93, 94, 95, 97, and 98, increase the 
last figure by unity. 
N. B. The areas for each integer, from 1 to 100, or one- 
twelfth part of this table only, has been examined. 
I have recomputed the Tables of Dr. Hutton, for all Nos. 
from 1 to 1000; and if the above corrections are made, the 
tables to which they apply will stand correct. 
March 1826. J. UTtiNnG. 
XXXIV. On the Phenomena connected with some Trap 
Dykes in Yorkshire and Durham. By the Rev. ADAM 
Sepewicx, M.A. F.R.S. M.G.S. Fellow of Trinity College, 
and Woodwardian Professor in the University of Cambridge*. 
Introduction. 
HE various phenomena presented by trap rocks have long 
engaged the attention of geologists. Different ages have 
been assigned to them, founded on their union with older or 
* From the Cambridge Philosophical Transactions, vol. ii. Part I. 
2D2 newer 
