THE ROCKS OF THE CLYDE DRAINAGE AREA. 547 



Volcanic Conglomerate and Breccia Ayrshire. 



Tuff This is found associated with the agglomerate. A very fine 

 variety known as Water-of- Ayr-stone was recently exposed in a fine 

 section at Troon. 



METAMORPHIC ROCKS. 



A group of these rocks are well exposed in Argyllshire, passing into Bute 

 and forming a rim around the granite area in Arrau. These are more fully 

 described by Mr. Peter Macnair, p. 414. Their geological age has not yet 

 been ascertained, but probably they are not younger than Silurian. 



They consist of altered igneous rocks, forming Epidiorites, Hornblende, 

 and Chlorite-schists and Serpentines. 



The rocks of sedimentary origin are altered to Gneissose-grits, Schistose- 

 grits, Schistose-greywackes, Albite-schists, Graphite-schists, Mica-schists, 

 Schistose-limestones, Phyllites, and Chlorite-epidote-schists. See the Green 

 beds of the Geology of Cowal. 



AQUEOUS OR SEDIMENTARY ROCKS. 

 (The Aqueous or Sedimentary Rocks are given in ascending geological order.) 



Silurian. 



Sandstones, Greywackes, Grits, Breccias, Conglomerates (Haggis rock). 

 Mudstones, Radiolarian Cherts, Limestones, etc. Ayrshire and Lanarkshire. 



Old Red Sandstone. 



Red Sandstones, Breccias and Conglomerates, Cornstones and Magnesian- 

 lirnestones Ayr, Lanark, Dumbarton, and Argyle shires. 



Carboniferous Rocks. 



The rocks of this formation are largely developed in the counties of 

 Lanark and Ayr, and consist of thick-bedded Limestones and Sandstones, 

 Grits, Conglomerates, Shales, Fireclays, Blackband Ironstones, and numerous 

 seams of Coal. 



Permian (?) or New Red Sandstone. 

 Red Sandstones Ayrshire. 



Pleistocene or Glacial Beds. 



Boulder-clay, Stratified clays, Sands and Gravels, Moraines, and Kames, 

 Erratic blocks, etc. 



These rocks are abundant all over the district. See " The Great Ice Age," 

 by Prof. James Geikie ; " The Drift or Glacial Deposits of Ayrshire/' by Mr. 

 John Smith ; and the Transactions of the Geological Society of Glasgorv. 



Recent Beds. 



Alluvium in the river valleys. 



Blown sand along the shore from Ardrossan to Avr : near Ardlamont 



.' 



Point, Argyllshire. 



Raised-Beaches along the shores of the river and firth of Clvde. 



/ 



Peat extensive tracts occur on many parts of the district, chiefly in 

 Lanark and Ayr shires, as at Shotts, Aird's Moss, etc. 



Soil Boulder-clay deposits being extensive in the district, a great part of 

 the soil is the weathered surface of that clay. There is also fine soil 

 produced by the disintegration of some of the volcanic rocks. 



Talus This is found at the base of cliffs and steep slopes. 



