i»94-95.] 2 35 



LARGE ERRATIC BOULDERS. 



{These number* follow consecutively upon last year's list.) 



6. Ordovician Grit, 8 ft. x 5 ft. 2 ins. x 4 ft. 6 ins. On Rough 

 Island, in Strangford Lough, near Comber, Co. Down. A low 

 drift-covered Island. Weight 13^ tons. 



7. Ordovician Grit and Slieve Croob Granite, with an intru- 

 sive vein of granitoid rock, 6 ft. x 4 ft. 9 ins. x 4 ft. 6 ins. On 

 Rough Island. Weight 9 tons. 



8. Slieve Lamagan Granite (Mourne Mountains), 17 ft. 7 ins. 

 x 10 ft. 6 ins. x 9 ft. 6 ins. high, resting on Ordovician Grits, 

 dipping at a high angle, having arrested the boulder in its 

 progress seawards. It has crushed and bent the upturned edges 

 ot the beds. Weight, 146 tons. The boulder rests on the edge 

 of a small brook, at the end of a cottage at Moneydarragh Beg, 

 on the coast road between Annalong and Ballymartin, County 

 Down. Much rounded. 



9. Carboniferous JN'illstone grit, at Blacklion, County Cavan, 

 13 ft. x 9 ft. x 1 ft 4 ins., resting on a neck of carboniferous 

 limestone, capping an isolated mass of the rock. The upper 

 surface sculptured with concentric circles. Weight, 8 tons. 

 Nearest outcrop 10 miles off. 



10. Gabbro with olivine, embedded in drift above Toboggan 

 field at Holywood, Co. Down, with fragments of flint, chalk, 

 basalt, and quartzite, measuring 6 ft. 9 ins. x 5 ft. x 3 ft. 4 ins. 

 Base not quite exposed. Long axis E. x N. and W. x S. Con- 

 siderably rounded and weathered. Weight, 9^ tons. 



11. "Ross's Rock" on sea shore opposite Macedon, White- 

 house, Co. Antrim, close to low tide mark. Fresh Olivine 

 dolerite, 7 ft. 2 ins. x 8 ft. :o ins. x 7 ft, considerably rounded. 

 Portions have been blasted away. Weight, 33 tons. 



12. Porphyry in boulder clay, found during the excavation 

 of South Woodburn reservoir at a height of 670 ft. o.d. 

 Weight about 2 tons. This rock closely resembles the intrusive 

 boss at Cushendun. 



Note — The boulders numbered 10 and 1 1 and the nodular 

 basalt mentioned in commencement of this report are from 

 yolcanic "necks" in Co. Antrim, (A. M'Henry, F.G.S.) 



