172 H. Faber c& W. K. Spencer— 



which are considered to be the most reliable are those given by Rowe 

 from measurements of the various zones in the Isle of "Wight and 

 Dorset. These are approximately as follows : — 



Isle of Wight. 



1,470 

 Further north a much greater thickness of the two upper zones is 

 suspected. Thus Rowe estimates that at least 400 feet of ' quadratus ' 

 chalk occur in Yorkshire. This cannot be the full thickness, for, 

 although Actinocamax ffranulatiis is eLhundant,s'pecimensoi A. quadratus, 

 the Belemnite characteristic of the upper part of the zone, have only 

 been met with in the very highest beds. We also know that 

 'mucronata' chalk of a higher horizon than that found in either the 

 Isle of Wight or Dorset is found in Norfolk, and that higher horizons 

 are represented on the Continent. Nevertheless, nobody could have 

 expected that results at all compai'able with those given in the 

 report would be obtained. 



The boring was taken through 2,742 feet, and yet the bottom of 

 the Chalk was not reached. Indeed, Ravn, from the fossil evidence, 

 regards the boring as only reaching the level of the zone of 

 A. quadratus. His table reads as follows: — 



feet. 

 Alluvial and diluvial ..... 34 



The Danian Chalk 86 



Upper ' Mucronata ' Chalk . . about 1,580 



Middle and Lower ' Mucronata ' Chalk about 400 

 ' Quadratus ' Chalk ... at least 642 



If this table is correct it is obvious that the ' mucronata ' chalk 

 may be of a greater thickness than the whole of the remaining Chalk, 

 and should therefore be capable of much more minute subdivision 

 than has hitherto been attempted. 



The following paragraphs give some general account of the methods 

 adopted and the lithological and palteontological evidence as to the 

 succession of the strata. It will be seen that the investigators have 

 good evidence to offer in support of their conclusions. 



Sistory of the Boring. 

 The boring was initiated as an attempt on the part of the 

 Frederiksberg District Council to obtain water. A depth of 230 feet 

 was reached, and then the search for water was abandoned. The 

 engineer, Marius Knudsen, offered, however, to proceed with the 

 boring in the interest of science at a very reduced cost, and the late 

 Professor TJssing was successful in obtaining a grant from the 



