1901-1902.] 21 



It is, however, the geologist that can best gain an idea of 

 the beauty and grandeur of the place; these headlands are 

 the products of a comparatively recent age, which geologists 

 term broadly the Tertiary Period. A great interval of 

 time elapsed between the formations represented by the 

 Chalk and the basalt found in these headlands. The Chalk 

 is the record of a time when 'the whole of the County 

 Antrim was submerged beneath the sea; the remains of the 

 deep sea fauna are still to be found as fossils embedded in the 

 chalk. Since these animals lived many changes in the earth 

 have taken place ; what was the old sea floor was elevated and 

 again became dry land, bleak and barren in many parts, as 

 the nature of the Chalk is such that its decomposition did not 

 result in forming a fertile soil such as now covers the country. 

 Instead of being rich in the material that plants require for 

 their growth and nourishment, the surface of the ground 

 was covered with flints such as may be seen on the top of 

 the chalk underlying the basalt in the Whitehead quarry. 

 Finely comminuted chalk particles and a thin ochreous bed 

 accumulated along river valleys, but even heje the vegetation 

 must have existed for long ages till the life in the adjoining 

 sea had changed — one species after another dying out or being 

 replaced by another form. At last, in the early part of the 

 Tertiary times, great earth disturbances took place all over 

 the County Antrim, and far north to the West of Scotland 

 and the Faroe Islands. Volcanoes burst forth in places, 

 large rents and fissures occurred in the chalk rocks or surface 

 rocks in this wide area; through these fissures and from 

 the volcanoes issued great flows of basalt in a highly heated 

 and fluidal condition. All this matter was of basic compo- 

 sition ; that is, it contained a much smaller percentage of 

 silica in its composition than does granite, which geologists 

 term an acid rock. Molten basic rocks retain their fluidity 

 for a longer period than do acid rocks, and the consequence 

 is the basalt flowed as sheets over large districts, overlapping 

 another at its edges. When one sheet had solidified there 

 may have been a period of rest during which the upper sur- 



