Vol. 57.] LANDSLIPS IN BOULDER-CLAY NEAR SCARBOROUGH. 295 



Fig. 1 is a reproduction of a photograph taken by myself on 

 September 26th, 1896 (Brit. Assoc. CoU. of Photos. 2483). It was 

 taken from the shore a little north of Osgodby Nab, the camera 

 pointing in a direction a little west of north. The rock of Scar- 

 borough Castle forms a prominent object in the distance. On the 

 right there is solid rock, a reef of sandstone below high-water 

 mark ; and on the left is a low cliff of Boulder-Clay, all of which 

 has slipped down from a higher level. 



When the clay is dry it has a tendency to crack vertically, and a 

 sort of columnar structure is produced. The large pillar of clay 

 seen in the view was, I believe, due to the action of the waves 

 on clay with such vertical cracks. 



1 have for several years noted details of landslips in the Drift 

 near Scarborough, and, as in other cases, ^ they may be classed as : 



(1) Mud-flows. 



(2) Earth-slips where the clay, though not actually mud, is at least partly 



ia a plastic condition. 



(3) Falls which, owing to the dryness of the clay, resemble rock-falls. 



(1) I have only seen small mud-Hows in Carnelian Bay ; but some 

 years ago I came upon one flowing across the footpath to Filey, 

 near Yons Nab. It was of considerable size ; in fact, I did not 

 venture to cross it. 



(2) Landslips of clay in a more or less plastic state are very 

 common. I have already said that a columnar structure is set up 

 in the dry clay, and after wet weather masses of this columnar clay 

 slip forward, and the columns become curved and distorted. 



During the slipping process a horizontal lamination is often 

 produced in the moister part of the clay, and very pretty twisted 

 structure may be observed which reminds one of gneissic banding. 

 An example of ' augen '-structure in the Contorted Drift at Beeston, 

 on the Norfolk coast, has been photographed by Mr. Strahan and 

 described by Mr. Clement Reid.^ A somewhat similar example is 

 shown in fig. 2, reproduced from a photograph which I took on 

 September 15th, 1900. It represents an area of about 360 square 

 feet of the bottom of the cliff a little south of Filey. It will be 

 noticed that the clay in this view, as well as in fig. 1, is full of 

 boulders. 



(3) When I was at Scarborough in May of the present year, I was 

 told that a considerable landslip had occurred in Carnelian Bay, 

 I believe that it happened on Whit Sunday, May 26th ; I visited 

 the Bay on the 28th, and found that the slip was in the nature of a 

 rock-fall. 



It originated from the spur of Drift which I have mentioned as 

 running out from the Boulder-Clay flat towards Osgodby Nab. 

 The Drift consists mainly of Boulder-Clay, but in places there is some 



^ Compare A. Baltzer's ' Ueber Bergstiirze in den Alpen ' Zurich, 1875 (re- 

 printed from the Jahrbuch des Schweiz. Alpenclub, vol. x). 



2 Proc. Geol. Assoc, vol. xiii (1893) p. 66. 



