278 Professor Harkness on 



On Annelid Tracks in the Equivalents of the Millstone Grits 

 in the South-west of the County of Clare. By Robert 

 Harkness, Esq., F.R.S.E., F.G.S., Professor of Geology, 

 Queen's College, Cork. (With a Plate.) 



The existence of Annelida during the palaeozoic formations 

 is manifested in two conditions. In the one, we have the 

 shelly envelope which invests the order Tubicola, in the form 

 of serpolites ; and in the other, the tracks of the orders Abran- 

 chia and Dorsi-branchiata are found impressed on deposits 

 which were, at one time, in a sufficiently soft state to receive 

 the impressions of the wanderings of these animals. 



Among the strata which have hitherto afforded annelid 

 tracks, those which, in the county of Clare, represent a portion 

 of the equivalents of the millstone grit, contain such tracks, in 

 their most perfect state of preservation in great abundance ; 

 and these strata also furnish evidence concerning the circum- 

 stances which prevailed during their deposition. 



The locality of these strata is the neighbourhood of Kilrush, 

 on the banks of the Shannon, in the southern portion of the 

 county. Here the deposits consist of strata which have a 

 flaggy character; these have been extensively wrought at 

 Money Point, about four miles east from Kilrush, and they 

 supply the flags which are commonly used in the towns of the 

 south of Ireland. The beds vary somewhat in their nature, 

 and with this circumstance they present different phenomena. 



The higher portion of the deposits contain flaggy beds of a 

 light gray colour, having sometimes a slight green tinge. These 

 flags are thin-bedded, and although devoid of annelid tracks, 

 they are marked with impressions of plants, principally cala- 

 mites, in compressed fragments. 



These higher flags also, in some instances, afford very beau- 

 tiful ripple-markings, which are frequently so perfect as to 

 enable us to judge from them of the direction of the wind 

 from whence they resulted ; and this appears, for the most 

 part, to have been from the south, the larger slopes of the 

 ripples pointing in that direction, the more perpendicular sides 

 being towards the north. 



