BEITISH ASS0CIATI05T MEETING AT CAMBRIDGE. 
461 
tion,' No. 8, 1862, has mentioned some of these facts, but it seemed worth 
while to throw them together in a distinct memorial, if only to draw atten- 
tion to an enterprising and patiently-conducted operation of great extent, 
by a single commercial firm, in obedience to geological principles. 
The wells (for there have been two attempts) are situated at the foot of 
Carrow and Bracondale Hill, Norwich, within a few yards of the river 
Wensum, the object of the deep sinking being to obtain a water, for use 
in the manufacture of starch, perfectly free from the impurities of "that 
found within the range of the chalk of the neighbourhood. 
The operation chosen is that of boring by Messrs. Mather and Piatt's 
machine. This machine consists of an iron boring-head, 8 or 10 feet in 
length, armed with strong chisels, suspended by a Jiat rope wound round a 
drum; the hammering or "jumping" motion being given by a special 
steam piston. The neck of the borer is formed with a screw, on which a 
collar connected with the flat rope works, the eflPect being that the borer is 
gradually twisted when at work, so that the chisels constantly strike on 
fresh points, and more thoroughly break up the materials met with. When 
a sufficient quantity has been thus broken up, the boring-head is removed 
and a " shell-pump" is let down having a valve at the base. On the pump 
being set in action, the loose material is forced into the shell and brought 
to the surface. In the hard chalk the rate of penetration accomplished 
was 20 to 25 feet a day for 500 feet. 
The first well failed in consequence of the iron tubing employed to case 
the bore slipping across and completely obstructing the action of the ma- 
chine, at a depth of 775 feet. 
The second is being sunk a few yards off, on the same level as the first. 
After a few feet of alluvium the borer passed through hard chalk, with 
flints at distances of about 6 or 7 feet apart, for 700 feet, with the exception 
of 10 feet at the depth of 500 feet, where the rock was soft, "like white 
lead," and of a rusty colour. Thence the hard chalk continued, with 
flints thicker together, viz. about 4 feet apart, to the depth of 1050 feet. 
Then 102 feet were pierced, of chalk free ivom. flints, to the Upper Green- 
sand, a stratum of about 6 feet, and next the gault for 36 feet : the whole 
boring being full of water to within 16 feet of the surface. 
In this ganlt, however, the greatest obstacle has been met, and the com- 
pletion of the work arrested for a considerable time past. This stratum is 
soft, so that the chisels, effective in the harder upper strata, are of little 
use. The material caves in from all sides as the instrument proceeds, and, 
unfortunately, the rope has broken more than once, leaving the boring- 
head below, and one now lying across the bore bafiles the engineer's 
efforts to remove it. 
The strata passed through are — 
Feet. 
Alluvium 
Hard chalk, with fliuts 
Soft chalk 
Hard chalk, as before 
Hard chalk, with flints; in closer layers 
Chalk, without flints .... 
Upper Greensand .... 
Gault, not yet passed through 
350 
102 J 
6 
12 
4831 
10 I 
1198 
The fossils brought up have not been very numerous, as might be ex- 
pected from the smallness of the bore, viz. twenty-one inches in diameter. 
