84 Mr. Charlesworth on the Crag-formation 



Horizontal layers of sand, with few shells, 15 feet. 



Layers of sand with numerous shells, inclined at an angle 

 of about 45°, showing a beautiful illustration of false stratifi- 

 cation, 4 feet. 



Coralline crag, 6 feet. This stratum had been exposed for 

 about seventy yards : in attempting to dig through it, I was 

 stopped by the appearance of water at the further depth of two 

 feet. 



Ramsholt. Red crag, 4 feet. Coralline crag, 7 feet. 



The two beds may be traced by the side of the Deben for 

 a considerable distance ; but owing to the quantity of brush- 

 wood and alluvial soil with which its banks are covered, their 

 position can only be advantageously seen in one spot, where 

 an excavation has been made. 



Sudboume Park. Here the red crag is absent : the inferior 

 stratum has been extensively, though but superficially, quar- 

 ried, its greatest depth being about twelve feet. 



The first striking peculiarity attending the coralline crag 

 in either of the above localities is its general uniformity of 

 character, having none of those variations in colour and stra- 

 tification which are so constantly met with in the upper beds. 

 Upon a closer examination we find it composed of siliceous 

 sand, with a large proportion of calcareous matter, sometimes 

 assuming a moist and slightly adhesive character, but never 

 blending with the dry loose soil of the accompanying strata, 

 a line of demarcation being always distinctly apparent*. We 

 see here none of those effects which are ascribed to the opera- 

 tion of tides and currents; there are no layers of sand alter- 

 nating with worn shells and pebbles: but the appearances are 

 those that would naturally be the result of a deposit going 

 forward during a tranquil state of the surrounding medium. 

 The remains of Testacea are extremely abundant, but furnish 

 no indications of having been subjected to the action of waves 

 on a pebbly shore : on the contrary, they are often little in- 

 ferior, in state of preservation, to those of the calcaire grossier. 

 Shells of the same species are often found so grouped together 

 that they could not possibly have been removed from their 

 original locality ; this is particularly the case with a large un- 

 described species of Balanus, occurring at Ramsholt some- 

 times in clusters of twenty or thirty. The moveable valves 

 still remaining in the interior of the shell. The following are 



* The separation between the red and the coralline crag is as distinctly 

 evident as that between the crag and the London clay ; there is nothing like 

 a gradual transition from one to the other. This is an important fact, as it 

 either indicates an intermediate period, or a sudden change in the opera- 

 tion of those causes which were in action when the crag was deposited. 



