20 PROCEEDINGS OF SOCIETIES. 



J. It. Kinahan, Esq., M.B., then read his paper — 



ON ANNELIDOID TRACKS IN THE ROCKS OF BRAY HEAD, COUNTY OF WICKLOW. 



All traces of animal remains, how indistinct soever, met with in 

 rocks so low down in the series as the Cambrian, mnst be looked on as 

 important. I have, therefore, ventured to bring before the Society- 

 to-night some unmistakeable animal traces which came under my no- 

 tice, during the past summer, in the Cambrian rocks of Bray Head, 

 county of Wicklow, and which, as far as I know, have been hitherto 

 undescribed, if not unnoticed. They occur in such abundance, and are 

 so unmistakeably marked, that there can be no difficulty in detecting 

 them. As to their nature, they would appear to be rather animal tracks 

 than the remains of animals, being the nlled-up burrows of some borer, 

 probably annelidan. They occur, for the most part, in company with 

 the beds of Oldhamia, although there would not appear to be any actual 

 connexion between the two. The chief beds of them occur on a small 

 cove situated on the N.E. side of Bray Head, immediately after round- 

 ing the hill from Bray. Here a number of low-lying, somewhat slant- 

 ing, beds of green and red slate occur, chiefly as detached rocks lying 

 off shore, but left dry by the tide at low water. The tracks are found 

 also in several places along the whole shore to Greystones, and also on 

 the top of the hill.* 



They occur as rounded tubuli, running either vertical to or in the 

 same direction as the bedding ; in the former case they present a circu- 

 lar, in the latter an ellipsoidal section. They vary much in appearance, 

 and are of every length, from 1 inch to upwards of 2 feet ; and, in dia- 

 meter, from the thickness of common sewing-thread to 0*3 inch and 

 upwards. There appear to be at least two different kinds of them : 

 some of those running in the same plane as the bedding, differing 

 much from the vertical tracks. These latter are generally long, and 

 of nearly the same diameter throughout, except at their upper ex- 

 tremity, where they spread out into a rounded knob, as though the ex- 

 tremity of the tubes were cupped. This form occurs also running nearly 

 horizontally to the beds ; the thread- sized tubuli differ from them also 

 chiefly in the fact of their occurring in pairs. The other set of fossils 

 are seldom more than an inch in length, and taper away to each end. ' 

 They occur best marked in a gritty red slate, with numerous shining 

 black particles through its substance. The thread worms occur, gene- 

 rally in the red beds, in immense profusion, closely resembling those 

 tracks detected by Mr. Salter in the Cambrian rocks of the Longmynd 

 (Quart. Journ. Geol. Soc, London, 1856, p. 246); they are here associated 

 with Oldhamia antiqua ; they occur also, though rarely, in greenish- 

 gray beds of Oldhamia radiata, being then in the direction of the bedding. 



* Since the above was read, the author, in company -with R. Scott, Esq., C.E., found, 

 in a compact green rock, traces of a different character from those here detailed, probably 

 molluscan, in company with remains similar to those fossils commonly called " Fucoids," 

 which he hopes to describe at a future period. 



