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TRILOBITES OF THE SKIDDAW SLATES. 



By J. POSTLETHWAITE, F.G.S. 

 (Read at the Bowness Annual Meeting. ) 



I believe the earliest record of the discovery of Trilobites in the 

 Skiddaw Slates occurs in the " Quarterly Journal," for November, 

 1866, in a note by Mr. Salter, "on two new species of Trilobites." 

 One of these, Phacops nicholsoni, was a Skiddaw Slate specimen, 

 found by Professor Harkness on Whiteside, about five miles west 

 of Keswick.* Ten years later, Mr. J. Clifton Ward's " Memoir 

 of the Geology of the Northern Part of the English Lake District" 

 was issued, containing an appendix by Mr. Etheridge, in which 

 four trilobites from the Skiddaw Slates are described, namely, 

 Niobe doveri, sp. nov., JEglina sp., Asaphus sp., and Cybele ovata, 

 sp. nov. The first three are from the cabinet of Mr. W. Kinsey 

 Dover, and are figured on plate 12 ; but the last, which was found 

 by Mr. Birkett, at Sandy Beck, south of Cockermouth, arrived too 

 late to be included in the plate. Since the publication of Mr. 

 Ward's memoir, a number of trilobites have been found in the 

 Skiddaw Slates by various collectors, differing in some points from 

 all known forms. Some of them resemble Illcenopsis thomsoni, 

 (Salter's "Monograph of British Trilobites," p. 213, plate 20,) in 

 the widely-divergent and deeply-cut axal furrows, reaching to the 

 front of the carapace, and in the short pointed and grooved pleurse, 



* The discovery of Trilobites in the Skiddaw Slates is also mentioned in 

 Murchison's "Siluria,"p. 146. 



