77 
Ordinary Meeting, January 23rd, 1872. 
E. W. Binney, F.B.S., F.G.S., President, in the Chair. 
The President exhibited to the meeting a large crystal 
of Selenite, of an irregular form and eight inches in length, 
given to him by Mr. Taylor, of Stretford. That gentleman 
informed him that it was from the mud which had been 
dredged out of the Suez Canal. When the mud came out 
of the dredge there was no appearance of crystals, but on its 
drying and being afterwards broken up, they were found in 
the mass. The President said that he had noticed the for- 
mation of similar but smaller crystals of selenite in the clay 
taken out of the London and North Western Kailway 
Tunnel during its formation through Primrose Hill. When 
the clay was first excavated there was no appearance of 
crystals in it, but after it had been exposed to the weather 
for a few months, on fracturing the clay these were found 
dispersed throughout its mass. He had also found crystals 
of selenite in the till or boulder clay at Egremont on the 
Mersey and at Blackpool; and the crystals, from their 
sharp edges, showed that they had been formed in situ, 
and had not come from a distance as many of the stones 
in the deposit had undoubtedly done. He had also seen in 
coal mines the formation of small crystals of selenite nearly 
an inch long in a few weeks. In this case their formation 
was evidently due to water charged with carbonate of lime 
coming into the shaft from the overlying drift beds and 
finding its way down into the workings, and there mixing 
with water containing sulphate of iron derived from decom- 
posed ii’on pyrites; the sulphuric acid of the iron going to 
Proceedings— Lit. & Phil. Soc— Yol. XI.— No. 8— Session 1871-2. 
