secretary's report. 
117 
those experienced on the previous day. Hubbard's Valley was 
the first spot visited, and here was seen a good section of the 
Lower Chalk, and some attention was bestowed on the terrace- 
like elevations at different points along the valley, which, it was 
suggested, were the remnants of the higher level at which the 
bed of a glacial overflow was cut, while the secondary valley 
at a lower level was the result of post-glacial denudation due 
to the action of the present stream. Hubbard's Valley itself 
constitutes a striking example of a glacial overflow due to the 
blocking up of the old valley of the stream, which in pre -glacial 
times flowed along the valley now traversed by the Lincoln to 
Louth Railway. According to the old theory, which is embodied 
in the memoir of the Geological Survey dealing with this district, 
the whole of the original valley of the stream which now courses 
between Hubbard's Hill and Fisher's Hill was filled by boulder- 
clay and other glacial debris, and that on the recession of the 
ice some local obstruction caused it to be easier for the stream 
to turn at a sharp angle and cut through the chalk hill. The 
Hubbard's Valley gorge was assumed to be the result of this, 
and it was also assumed that the original valley was re-excavated. 
The progress of glacial geology, however, has given rise to 
some changes of view, and Professor Kendall pointed out 
that there was no stream to re-excavate the old valley, as 
the water had been diverted, and his theory and that of his 
colleague is that the North Sea ice-sheet blocked the valley, 
caused the accumulation of a lake which overflowed along the 
line of Hubbard's Valley, and that the deposits in the old valley 
were left there on the recession of the ice. Some small valleys 
in the direction of Welton were then exammed, and these were 
considered to be of prior formation to Hubbard's Valley. On 
the way to Welton Vale small boulders were found in the fields, 
including quartz-porphhry, jasper frojn Scotland, Scottish por- 
phyrite, hornblende gneiss, and Norwecian rocks. 
Welton Vale was considered to have been formed in almost 
the same manner as Hubbard's Valley, and Professor Kendall 
was of opinion that the overflow had filled the valley from side 
to side, and he pointed out how the sides of this beautiful gorge 
resembled the banks of a stream, with alternating steep and 
