VI PEEFACE. 



to say what ought not to be included in a book on Field 

 Geology. The object aimed at has been to include herein 

 those that are absolutely necessary, in as small a com- 

 pass as is consistent with the purpose in view. 



My colleague, Mr. Jukes-Browne, was good enough 

 to undertake the section on Palaeontology, at a time 

 when, unfortunately, his state of health was not as good 

 as could be desired. For this reason the list of charac- 

 teristic fossils following his work was not prepared by 

 him, and it is, perhaps, far from being as complete, and 

 probably as accurate, as it would otherwise have been. 



The new rules for finding direction of true dip, when 

 first published in the Geological Magazine for May 

 1876, gave rise to some useful criticism; it was then too 

 late to make any alteration in the text or the figures,, 

 but a footnote has been inserted to give the resulting 

 modification. 



W. HENBY PENNING. 



CALDECOTE, GAMES. 

 August, 1876. 



