258 A HISTORY OF LONGRIDGE. [Chap. 12. 



boulders and pebbles associated with the boulder clay, differing al- 

 together from the rooks of the neighbourhood. la the recent 

 excavations connected with the Eibblo Dock, pebbles or boulders of 

 the following rocks were found : — 



Granites, Agglomerates, 



Diorites, Volcanic Tuff, 



Porphyrites, Carboniferous Limestone. 



Quartzites, Ganister, 



and several others still undetermined. The nearest locality for any of 

 the above named igneoim rocks is in the extreme north-west of 

 Lancashire, but probably some of the stones were brought from even 

 greater distances. 



The Glacial Deposits are well developed in the Longridge district, 

 and may be seen in sections at various places along the banks of the 

 Eibble, notably at Eibchester, where the fossils of the Drift are obtain- 

 able. Visitors to Blackpool during the summer months may spend a 

 profitable hour in collecting shells from the Drift Gravel of the cliff 

 immediately below " Uncle Tom's Cabin." These may then be com- 

 pared with the shells of existing species found on the shore at low 

 water, and with those found in the gravels at Eibchester. 



Eesting upon the surface of the Boulder Clay there is usually a 

 more recent deposit. This may consist of alluvium, of peat, of river 

 gravel, or it may be simply the insoluble detritus worn from the 

 eurroimding rocks and spread over the land by the action of running 

 water, wind, &o. It is generally of a dark colour, owing to the 

 presence of decaying organic matter, and forms the soil upon which 

 the vegetation of the district is developed. 



