Sectional Officers’ Reports. 307 
Other examples of limestone concretions may be found in 
the Lias Clay, but these, although more completely zoned than 
those from the Witham Valley, never exceed about one-eighth of 
an inch in diameter. A narrow band of ferruginous limestone, 
opened out in Rudd’s brickyard in the upper Lias just South of 
Grantham, yielded a considerable number of such pisolitic 
concretions, which, when sectioned, make a very interesting slide 
for the microscope. 
CALCITE SAND AT BELTON, GRANTHAM. 
At the East end of Belton Park, on the North side of the 
brook supplying the villa pond, there is a small spring issuing 
from the base of the Marlstone-Rock Bed, (Middle Lias Ironstone). 
This spring-water has been collected into a catch pit and conveyed 
by gravitation through a lead pipe to a cistern a little over a mile 
away. 
Within the tank into which the water flows, there 
accumulates from time to time, a deposit of Calcite in the form 
of perfect rhombohedral crystals varying in size up to the one- 
hundredth of an inch side. 
The precipitation of Carbonate of Lime from water collected 
in the Limestone and Ferruginous Limestone Rocks is not 
unusual, but it occurs generally in the amorphous or sub-crystalline 
condition of stalactite, stalagmite, or tufa. The perfect condition 
of the crystals precipitated from the Belton water is therefore 
unusual and of peculiar interest. 
During the summer of IgI1I the spring was yielding only 
about 500 gallons per day, but the deposit of “sand” when the 
cistern had its annual cleaning, would quite fill a two gallons 
measure, so that the deposit is not small, and it is evident that 
some definite cause is at work producing the crystals. Also, similar 
deposits have been known to accumulate in this cistern for at 
least 30 years, or more, past. 
In seeking an explanation of this phenomenon it should be 
remarked that no trace whatever of a deposit of calcite, in any 
