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of it from all possible sources as a means of cheering me 
when crossing its dreary expanse, and these materials I am 
about to place at your disposal. The Heath, as you are well 
aware, extends almost from Sleaford to Lincoln in an 
irregular pear-shaped form about sixteen miles long. Its 
surface is by no means flat, for in the first place it rises 
gradually from under the " Oxford " clay stratum on the east, 
and terminates in a steep ridge as it sinks suddenly towards 
the " Has " district on the west ; but besides this, its whole 
surface consists of a series of gentle undulations resembling 
those of the Atlantic after a storm, and the straight white 
road topping these in succession on its way northwards, does 
not very inaptly represent the foamy track of some vast 
steam-ship, such as the Great Eastern leaves behind her in 
calm weather, while the shadows of the little clouds passing 
over the surface of the Heath, just as they do on the real 
ocean, add to the correctness of the comparison. But now 
let us see what our subject is really made of by slicing in two 
one of its ridges. Beneath a thin layer of light soil, from 
9 to 18 inches in depth, we shall find a thick stratum of 
limestone, belonging to what geologists call the series of 
the " great oolite.'' At some very remote period, and during 
countless centuries, water was gradually depositing the limy 
particles with which it was charged on the clay beneath it, 
until it formed a coating many feet in thickness, sometimes 
sympathising with the undulations of the subsoil, and some- 
times drifting into its deeper hollows, so as to cause a 
considerable degree of variation in its thickness. It has 
also been subjected to other subsequent disturbing causes* 
from the pent-up powers of the earth's deeper recesses. A 
remarkable example of this may be seen in the second 
railway- cutting between Sleaford and Grantham, where an 
upward thrust from below is exhibited, forming a rounded 
eminence beset with fissures, now filled in with earth that 
