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lengthened along the cleavage planes thus produced. If the planes of 

 cleavage are mistaken for those of bedding, errors of the most serious 

 character might arise in working out the structure of a tract of country. 

 Hence, the man who first clearly pointed out the difference between these 

 two structural planes, did a great and worthy work, which should receive 

 its due acknowledgment from the after-workers. And this did Jonathan 

 Otley. 



Professor PhiUips, in his exhaustive Report on "Cleavage and 

 Foliation in Rocks," published in the British Association Report for 1856, 

 page 369, thus mentions Otley's work. 



"The earliest notice of a real and firm distinction between cleavage 

 and stratification, derived from English examples, which I have met with, is 

 in Otley's 'Concise description of the English Lakes' (Keswick 1823, 

 an earlier publication in Kirkby Lonsdale Magazine, 1820). He speaks 

 of the beds of slate with frequently vertical cleavage, and adds — ' but it 

 is foimd in various degrees of incliftation, both with respect to the horizon 

 and planes of stratification.^ Sedgwick, in 1835, defined the character 

 of slaty cleavage, the fundamental generalization, due to him, is that 

 'cleavage is a peculiar structure impressed on certain rocks, and in certain 

 regions, by the operation of some very extensive cause, operating after 

 the stratified rocks had undergone great displacement.' " 



With these remarks on Otley's geological work, I am content to leave 

 his character as a geologist. His observations on various points of 

 geological detail were numerous and important, but his position among 

 English geologists of note will ever rest upon his work in the first classi- 

 fication (into three divisions,) of the rocks of the Lake District, and in 

 the first drawing attention to the fundamental distinction between 

 cleavage and bedding. Jonathan Otley worked according to his light, 

 and used the talents given him, in a quiet, unobtrusive manner, which 

 bringeth its own reward, even that of a contented and happy spirit, joying 

 in the works of nature. 



As a further illustration of Otley's work, and the estimation he was 

 held in by Professor Sedgwick, the following series of letters are of great 

 interest. They date from the year 1827 to 1855, ^^^^ 7^^"^ before Otley's 

 death at the advanced age of ninety. 



