238 Geological Society: — 
which, is continuous with that of the Calceby beck, while the 
Telford beck, which appears to have originally been a tributary of 
the Calceby stream, now runs into the Steeping ; and its peculiar 
course illustrates the manner in which this and other streams have 
been diverted from their original channels. 
2. Valleys of the Trent and Witham. — The Trent flows in a 
transverse valley as far as Xewark, and is then suddenly deflected 
northward into a longitudinal valley. Proofs are given that its 
ancient course was eastward, by Lincoln to the Fens ; and a remark- 
able series of old river-gravels are described, which mark out the 
former courses of the rivers Trent, Witham, and Devon. 
The longitudinal valley along which the Trent now flows, from 
Kewark to Gainsborough, may have been excavated in the first 
instance by a tributary of the Idle ; the recession of this valley 
towards that of the Trent (assisted by other causes) probably led to 
the diversion of the latter river from its original transverse valley 
into that of the Humber. 
The study of these changes in the river-courses of Lincolnshire 
leads to the conclusion that whenever a succession of ridges and 
depressions has been developed out of the surface of a country, a 
river crossing any one of the longitudinal valleys which happens to 
stretch to the sea-coast is liable to diversion by the backward exten- 
sion of a stream draining directly into the sea from the termination 
of the longitudinal valley. 
3. " On the Section at Hordwell Cliffs, from the top of the Lower 
Headon to the base of the Upper Bagshot Sands." By the late E. 
B. Tawney, Esq., M.A., F.G.S., and H. Keeping, Esq., of the Wood- 
wardian Museum. Communicated by the Rev. Osmond Fisher, 
M.A., F.G.S. 
The authors, after a brief sketch of the literature of the subject 
and of the method which they have adopted in measuring the beds 
in the Hordwell section, passed on to describe these, viz. the fresh- 
water Lower Headon series and the so-called Upper Bagshot Sands 
of the Geological Survey. They make the whole thickness of the 
former 83| feet. The bed numbered 32 in their section they 
identified with the Howledge Limestone on the other side of the 
Solent. It is almost the highest seen in the section, and underlies 
the true Middle Headon, which is now no longer exposed. The 
authors pointed out that in their opinion the late Marchioness of 
Hastings and Dr. Wright have somewhat misapprehended the posi- 
tion of these several beds. Details were then given of the remainder 
of the section, and comparisons made with the details published by 
former authors ; after which the authors described the underlying 
estuarine series, or Upper Bagshot Sands, which has a thickness of 
17| feet. 
4. " On some new or imperfectly known Madreporaria from the 
Coral Rag and Portland Oolite of the Counties of Wilts, Oxford. 
Cambridge, and York." By R F. Tomes. Esq., F.G.S. 
