282 Walmsley: Coast Changes at Robin Hood’s Bay. 
Middle Sands slid down gradually, and was finally thrust on 
to the beach as in Fig. 2. By the end of the year 1911, however,’ 
this was eroded by the sea, and the margin was restored to 
its original position as in Fig. 3. During 1912 and 1913 the 
upper beds have been again slipping as shown in the photo- 
graph, and the margin of the clay is now further out than it was 
in IgIo (Fig 4). 
Assisted by the water from the fields above, and from the 
springs, the cliff proper resembles a tremendous chute, delivering 
excellent agricultural land into the sea, at the rate of many 
square yards per year! One of the peculiarities of this Middle 
Sands is the persistent occurrence therein of thin beds of coal 
pebbles. This coal is identical in structure with that found 
in the Lower Estuarine Beds which cap the hills around Robin 
Hood’s Bay, and the whole bed is similar to what we might 
expect to be the result of the denudation of the Estuarine 
Beds. 
It was in one of the gravelly patches of the Boulder Clay at 
Stoupe Beck, that I recently found a portion of a Mammoth 
tusk in good preservation. One side of it shows decided 
evidences of glaciation, and several geologists to whom I have 
shown it express the opinion that it is a genuine ice ‘ boulder.’ * 
Since the photographs reproduced were taken, the slipping 
of the cliff on the southern part of Bay Town has reached serious 
proportions. As may be seen by the map, most of the slipping 
has been in a seawardly direction, but owing to the high slope 
of the cliff above the Gas-house, a considerable amount of 
material has moved in this direction, as is shown clearly by 
the ‘ slickensliding’ on the faces of the planes of movement. 
The effect of this movement is evident in the stables and ware- 
house marked X! where the furthermost walls are bulging in 
an alarming manner, in one place projecting ro inches from 
the jambs of the door. This bulging has taken place within 
the last seven months, and coincides with the movements of 
the cliff above. The Gasometer X* would also seem to be 
threatened, but up to the present there are no cracks in the 
solid surrounding retaining wall. On the seaward side the 
slipping has been much more extensive, and one house, marked 
X* now occupied, appears unsafe for habitation. 
The opinion has been expressed locally that the clay is 
now settled down, and that nothing is to be feared for many 
years to come. This opinion, however, I fear is not reliable, 
and if proper protection to the property has to be given. it 
must be in the form of a substantial wall, which would finally 
reduce the slope of the cliff and increase its stability. 
* Its good state is doubtless due to the fact that it was transported in 
a frozen mass. It is at present in the museum at Hull.—Ed. 
Naturalist,’ 
