346 THE PONIES OF CONNEMARA. 



Had all the rocks in the west of Galway consisted of quartzite like the 

 Twelve Bens, or of granite such as occupies a wide area to the north of 

 Galway Bay, or of metamorphosed rocks such as underlie and predispose to 

 the formation of the extensive bogs of Mayo, Connemara would never have 

 been famous for ponies. Green plants are incapable of growing unless sup- 

 plied with lime, and they only flourish when lime is present in the soil in 

 sufficient quantity and when it is accompanied by certain other chemical 

 substances, such as potash and phosphoric acid. In most cases the soil 

 is indebted for its lime to the rocks over or near which it lies. It is, how- 

 ever, well to remember that some limestone districts are extremely barren, 

 while some districts destitute of limestone deposits are highly fertile, and 

 that in some areas the whole of the soil is of foreign origin.* 



In the west of Galway, notwithstanding abundant evidence of glaciation 

 and the presence of numerous glacial deposits in the uplands as well as in 

 the valleys, the soil has, to a very large extent, resulted from the weathering 

 of the native rocks. According to the geological survey, a considerable 

 number of glacial deposits occur between Lough Mask and Killary Harbour 

 and over the low-lying area extending between the wide upper portion of 

 Lough Corrib and the Atlantic, i.e., in Connemara proper. Other patches 

 of boulder clay occur in the southern granitic area between Connemara 

 proper and Galway Bay. Some of these deposits doubtless consist of 

 drift boulder clay carried from the great central plain, but the majority are 

 of local origin — relics of district and local glaciers. The boulder clay from 

 the central plain is likely to be rich in partially disintegrated carboniferous 

 limestone, while the local deposits north of the granitic area are doubtless 

 rich in lime-salts derived from the schists and basic igneous rocks in the 

 vicinity of Lough Inagh and other centres from which the ice radiated 

 during the latter part of the glacial epoch. 



In the extensive granitic region north of Galway Bay the patches of 

 boulder clay are mostly small— they often form fertile spots in an otherwise 

 unproductive district. There is, however, a glacial deposit of considerable 

 extent near the centre of the southern section, but owing to its being in 

 great part covered by bog, it is of little value. 



With the exception of the boulder clays, alluvial deposits and belts and 

 mounds of wind-blown sand, the soil of Connemara has almost entirely 

 been derived from the weathering of schists and igneous rocks. 



A glance at a geological map of Ireland shows that a wide central 

 band of Lower Silurian rocks extends right across Connemara from the 

 upper part of Lough Corrib to the Atlantic. To the north of this, occupy- 

 ing the uplands, there is a somewhat crescent-shaped mass (about 150 

 square miles in extent) of Upper Silurian rocks, while the south, as already 

 indicated, consists almost entirely of granite. A more careful inspection 

 reveals the fact that the Lower Silurian and, to a less extent, the Upper 

 Silurian areas include a large amount of limestone and numerous igneous 

 dykes. The limestone mainly occurs in narrow, often nearly parallel, 

 bands ; but there is a considerable stretch of carboniferous limestone occupy- 

 ing a triangular area between Lough Corrib and the railway from Galway to 

 Oughterard. The limestone bands are especially abundant between 

 Oughterard and Clifden, to the north of the Maumturk Mountains, and 



* A striking instance of this we have in the southern states of New England, where over an 

 area of nearly 4,000,000 square miles the soil, with the exception of a few insignificant patches, 

 consists of boulder clay carried thither by ice during the glacial epoch. 



