222 PROCEEDINGS OF THE GEOLOGICAL SOCIETI. [Jan. 22^ 



of the chalk and clay, while no such fault is represented in Professor 

 Phillips's section of this part of the coast*. I regret that, owing to 

 the great landslips at this spot, I found it impossible to arrive at a 

 result which I could consider absolutely conclusive on this subject ; 

 I am, however, very strongly of the opinion, arrived at from an ex- 

 amination of the beds along the sides of Speeton Gap, that such a 

 fault does exist, and that it is a downthrow towards the south, by 

 which the Chalk beds are brought to a relatively lower level than 

 those of the Speeton Clay. The direction of this fault appears to 

 coincide almost exactly with that of the Speeton Gap, and it probably 

 extends for some distance inland : its amount would appear to be 

 very considerable ; but I am unable to give even an approximate 

 estimate of it. 



The difficulty of reading the Speeton section is increased by the 

 numerous landslips which occur along its course ; of these it is 

 necessary to take account before attempting to arrive at the true 

 succession of beds. Besides a great number of smaller masses of the 

 drift and higher portions of the clay which have descended from 

 their proper position and now occupy various levels down to that of 

 high-water mark, there are thi^ee landshps which have produced very 

 great and striking alterations in the features of the section. South 

 of Speeton Gap tbe junction of the chalk and clay is altogether con- 

 cealed, owing to the fact that great masses of the former have slipped 

 over the latter, and now form an underchff which extends for more 

 than half a mile in length, and rises to a height of upwards of 100 

 feet. In Black Cliff another landslip has occurred, by which a 

 mass consisting of the highest beds of Speeton Clay, capped by red 

 and white chalk rubble, has descended 150 feet below its true level, 

 and now occupies the base of the cliff for a length of 150 yards. 

 Lastly, a similar, though smaller, shp has taken place in the southern 

 part of Xew Closes Cliff, by which the highest beds at that part of 

 the cliff are brought down to within 50 feet of the sea-level. 



The thickness of the mass of clays composing the cliff I have- 

 been describing is about 500 feet, that of the beds below, which 

 are so very partially exposed, cannot be estimated ; but, considering 

 the breadth of their outcrop, it must be very great. I shall now 

 proceed to show that this great mass of clays is by no means uni- 

 form, either in lithological or palaeontological characters, but that, 

 on the contrary, it exhibits a number of weU-marked subdivisions. 

 At least seven such divisions, each distinguished by a clearly defined 

 fauna, occur in this thick series of clays, some of which can be cor- 

 related with other British deposits already well known, while others 

 are of higher interest as presenting us vrith representatives of for- 

 mations not hitherto recognized in this country. The three upper 

 of these divisions belong to the Neocomian System, the four lower to 

 the Jurassic. 



Thus it will appear that the Speeton Clay, far from being a single 

 insignificant bed, is a formation at least equal in thichiess, and, I 



* Greologj of Yorkshire, pi. 3. 



