82 



Turning, then, to some examples which otir own district 

 presents, we find traces of a recent deposit of an impure Carbonate 

 of Lime, or Calc-tufa, connected with many of the streams issuing 

 from the Cotteswolds. Frequently around a spring, or at the 

 sides of a little streamlet in the higher parts of our combes 

 and valleys, stems, leaves, and exposed roots of plants may be 

 found incrusted with lime, and occasionally considerable 

 acciamulations of this deposit have taken place in such localities ; 

 but it is near the bases of the hills that we find far more important 

 deposits, where the quantity of water issuing from these lower 

 springs is great, and where from longer contact with the strata 

 of the hills the water is more highly charged with lime. 



One such instance is found at Chalford, where at a very narrow 

 part of that picturesque valley there issue a series of fine springs 

 of limpid water. These springs are very numerous, and extend 

 for about 300 yards along the foot of the hill on the south side 

 of the valley, and at about 30 ft. above the level of the stream 

 which flows down the Chalford valley. Formerly these springs 

 were well seen ; but in the construction of the Great Western 

 Railway, about 1842, the sources of most of them were covered 

 over, and much of the water now issues from artificial culverts. 

 When the railway was made a large quantity of Tufa was removed 

 and used for ornamental purposes in gardens and ferneries, and 

 some was used as building material, as in the retainmg wall of 

 the embankment of the railway, where may now be seen many 

 squared blocks of Tufa, and on the capping of the wall there 

 are also blocks of it, which have withstood the effects of frost 

 admirably for 30 years. 



The occurrence of Calc-tufa at the little town of Dursley and in 

 its vicinity is well known, both on account of the extent of the 

 deposits and from the practical use which has been made of it 

 for building purposes. The situation of this town is highly 

 picturesque ; placed in a very narrow valley, and shut in by lofty 

 hills whose broken outlines and deeply indented combes are finely 

 wooded. The Cam river, which flows close to the town, here 

 receives accession from numerous springs, the largest of which, 

 the "Broadwell," rises in the middle of the town. This remarkably 



