THE LOWER PALEOZOIC TRILOBITES OF THE GIRYAX 

 DISTRICT, AYRSHIRE. 



INTRODUCTION. 



Since the publication of the 'Monograph of the Girvan Silurian Fossils 'by 

 Prof. H. A. Nicholson and Mr. R. Etheridge, jun., in 1880, no detailed palgeonto- 

 logical study of the rich trilobitic fauna of the Girvan area seems to have been 

 made. In the meantime, however, a considerable amount of new material has 

 been accumulated and affords scope for further work. Mrs. Robert Gray in 

 particular has added considerably to her collection from which the majority 

 of the specimens figured in the above-mentioned Monograph were selected ; and, 

 being desirous of having the new specimens examined in conjunct ion with a 

 revision of the old material, she entrusted the task to me through the kind instru- 

 mentality of Dr. F. A. Bather, of the British Museum. The whole, therefore, of 

 Mrs. Gray's unequalled collection has been placed in my hands at Cambridge, and 

 the study of it has been supplemented by the examination of the trilobites from 

 the same district in the Museum of Practical Geology, Jermyn Street; the Edin- 

 burgh Museum; the British Museum; the Hunterian Museum, Glasgow; and the 

 Woodwardian Museum, Cambridge. Among these collections are the types of all 

 the species described by Prof. Nicholson and Mr. Etheridge in their Monograph, 

 besides the specimens from which the lists of species given in the Geological Survey 

 Memoir on the Silurian Rocks of Scotland (published in 1899) were compiled. 



The bibliography of the district is fully given in the last-mentioned Memoir, 

 and need not be repeated ; while the chief palseontological works on the Silurian 

 fossils are enumerated in a list at the beginning of the Monograph by Prof. 

 Nicholson and Mr. Etheridge. 



The stratigraphical classification of the Girvan beds here adopted is that given 

 in the recent Memoir; and it is based on that drawn up in 1882 ] by I 'inf. 



1 'Quart. Journ. Gteol. Sue.,' vol. xxxviii, pp. 537 — 666. 



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