378 Reports and Proceedings— 
In a country which is traversed by a series of escarpments or hill- 
ranges, the valleys by which its drainage is effected are usually 
separable into two sets or systems, one parallel to the strike of the 
ridges, and the other more or less at right angles to the same. The 
origin of these longitudinal and transverse valleys has been ex- 
plained by Mr. Jukes, who has shown that the course of a stream 
flowing in a transverse valley and crossing a longitudinal valley is 
not likely to be diverted, unless something happens to cut a deeper 
channel down the longitudinal valley to the sea. The possibility of 
this will depend upon the strike of the rocks and the trend of the 
sea-coast ; where a longitudinal valley or the interspace between two- 
escarpments abuts upon the coast, and is occupied by a stream 
running into the sea, the process of erosion may carry the sources of 
this stream back so far as to intercept the waters of a transverse 
river crossing a higher part of the same general depression or inter- 
space. The author believes that this has happened in some instances, 
and notably in the case of two Lincolnshire valleys. 
(1) Valleys of the Steeping and Calceby Becks.—These two streams 
have their sources near one another in the vicinity of Telford. The 
Calceby beck occupies a transverse valley, and flows north-east to 
the Saltfleet marshes; the Steeping flows in a longitudinal valley 
south-east to the fens by Wainfleet. 
The disposition of the Boulder-clays (Hessle and purple) along 
the eastern border of the chalk wolds affords a criterion of the rela- 
tive age of the valleys which open eastward, some being older and 
some newer than the formation of those clays. Glacial clays and 
gravels are found continuously along the Calceby valley, and occur 
also in the valleys of its tributaries; the same deposits sweep round 
the southern end of the Wold hills into the entrance of the Steeping 
valley, but do not run into it; hence it would appear that the Steep- 
ing valley is of later date than the Calceby valley. 
Facts were given in support of the hypothesis that the Steeping 
valley has been rapidly developed and enlarged by the combined 
action of rain and springs, and that its backward extension has 
caused the interception of certain streams that originally flowed into 
the Calceby valley. As a matter of fact, the Steeping valley now 
extends behind the abrupt termination of a broad transverse valley, 
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 trans- 
verse valley as far as Newark, and is then suddenly deflected north- 
ward into a longitudinal valley. Proofs are given that its ancient 
course was eastward, by Lincoln to the Fens; and a remarkable 
series of old river-gravels are described, which mark out the former 
courses of the rivers T'rent, Witham, and Devon. 
The longitudinal valley along which the Trent now flows, from 
Newark to Gainsborough, may have been excavated in the first: 
