Vol. 62.] THE CARBONIFEROUS ROCKS AT RUSH. 275 



13. The Carboniferous Rocks at Rush {County Dublin). By 

 Charles Alfred Matley, D.Sc, F.G.S. With an Account of 

 the Faunae Succession and Correlation. By Arthur Yaughan, 

 B.A., D.Sc., F.G.S. (Read December 20th, 1905.) 



[Plates XXIX & XXX— Fossils.] 



Contents. 



Page 



I. Introduction 275 



II. General Structure and Sequence 278 



III. Description of the Rocks 280 



IV. Summary of Conclusions 295 



V. Faunal Lists 295 



VI. Account of the Faunal Succession and Correlation 299 



VII. Notes on the Genera and Species cited in the Faunal Lists ... 305 



I. Introduction. [C. A. M.] 



Although Carboniferous rocks form the rock-floor of the greater 

 portion of the County of Dublin, they are so much concealed inland 

 by Glacial Drift as to render their structure and relationships usually 

 obscure. On the coast, however, they crop out in several very good 

 sections, especially near Malahide, about 4 miles north of Dublin 

 Bay, and at Rush, about 6 miles still farther north. The latter is 

 the more extensive and interesting of these two. 



From the shore south of Rush village, extending northward past 

 Loughshinny to within a mile of Skerries — a distance in all of 

 about 5 miles — the Lower Carboniferous rocks are splendidly 

 exposed : the outcrops being only interrupted occasionally, where 

 the shore is covered by sand, or the Glacial Drift descends to sea- 

 level. At the suggestion of Mr. G. W. Lamplugh, F.R.S., and 

 tempted by the interesting character of the rocks themselves, I was 

 induced (during a temporary residence in Ireland) to make a detailed 

 examination of these beds. In order to understand the coast-section 

 in full detail, a horizontal section of the beds, as shown in the 

 cliffs and along the rocky shore, has been prepared for the whole 

 distance on the scale of 1 inch to 10 feet. 1 As, however, fossils 

 have up to the present been collected only from the rocks near 

 Rush, that is to say at the southern end of the line of section, the 

 present communication will be restricted to that part of the area; 



1 The section does not pretend to absolute accuracy. The base-line has been 

 roughly measured on the ground with a 10-foot string weighted at one end by 

 a stone, the details of the exposure being sketched in at the same time. But 

 the scale is sufficient to allow of all the important beds being shown and 

 the structure being recorded in considerable detail, while the horizons from 

 which the fossils have been obtained are thus fixed with much precision. The 

 thicknesses of beds, as given in the following pages, are calculated from the 

 section and checked with the 25-inch map. The margin of error should, 

 therefore, not exceed 10 per cent. 



