1910-1911.] 267 



prize for the best set of photographs illustrative of the geology of 

 the district visited at the previous excursion offered by the Vice- 

 President was won by Mr. D. J. Hogg. 



On Saturday, the 2nd July, a party composed exclusively of 

 members of the various Sections visited Armagh district. 



The Geological Section was well represented on the excursion. 

 Mr. Robert Bell acted as conductor. The route travelled was 

 north-west to the Carboniferous limestone quarries at Carrick- 

 aloughran, then south-west to the Navan quarry, from which the 

 return was made to the Cathedral city. 



At Carrickaloughran, the limestone, which belongs to the 

 lower series is no longer worked. The present interest of the 

 quarry is a huge dyke of basalt locally called " whinstone," over 20 

 feet in width, which rises almost vertically through a fissure in the 

 limestone beds, cutting the nearly horizontal bedding planes of the 

 latter almost at right angles. The basalt is fine-grained and 

 exceedingly hard. It possesses sub-columnar structure in the mass, 

 and is quarried to the depth of almost 50 feet for road-metalling 

 purposes. In the same quarry there are three other dykes of 

 smaller dimensions. The intrusion of the basic igneous lava has 

 produced very varied metamorphic results in the limestone rocks 

 into which it was forced. The limestone is covered with a 

 variable depth of rubbly drift and boulder-clay. Evidences of ice 

 action are clearly apparent in the glaciated condition of the surface 

 rocks. Many fossils were collected both here and at Navan. 



A short distance south-west of the Carrickaloughran quarry is 

 an extensive low-level esker-like deposit of sands and gravels. 

 This has been extensively worked locally for building sand. Some 

 interesting sections are exposed in the pits, from the clayey sands 

 in one of which a member of the club, Mr. Joseph Wright, F.G.S., 

 recently obtained a number of foraminifera. The clay bands 



