54 



torn, the entire quantity filtered away in a leu* hours. There being 

 no natural supply of water on the Park except surface drainage, it. be- 

 came a matter of vital importance to make an artificial bottom to 

 the Lake, which should be as nearly impervious to water as possible. 

 This was dune as follows*: the excavation was carried to a depth of one 

 foot below the final bottom of the Lake, and a layer six inches in 

 thickness of stiff clayey loam was laid on evenly, and carted over and 

 otherwise worked, without special care; upon this was laid six inches 

 of blue clay of very fair quality, as it was found in the pit, without 

 other mixture with sand or gravel. This layer of cday was thoroughly wet 

 and carefully cut and worked over with shovels, care being taken to have 

 the water and working reach the lower layer of clayey loam. The, 

 puddling on the slopes of the Lake was protected from the action of 

 the sun during the progress of the work, by a layer of gravel and 

 stone three inches thick. These will also protect the slopes from the 

 action of the waves in summer. The slopes of the main Lake are 

 made with an inclination of one foot vertical to five feet horizontal. 

 The puddling on the bottom of the Lake was covered with water as it 

 was laid, and thus protected from injury by the sun. 



The clayey loam which was used for the lower layer of the puddle 

 was found in great abundance, over nearly the entire area to be occu- 

 pied by the Lake, just beneath the surface soil. The blue clay 

 used was found in the Hart range, and is a remarkable deposit. A 

 s< si i reh was made by borings on all portions of the Park where clay 

 was likely to be found, and at this point it was discovered about three 

 feet below the surface. This covering was removed, and the excava- 

 tion of the clay carried to a depth of twenty-three feet before the bot- 

 tom of the deposit was reached. Immediately below the clay is a 

 mass of boulders, which rest upon a bed of sand. Over seven thousand 

 yards of clay have been taken from this deposit, and the indications 

 are that a large quantity still remains. 



A temporary dam, with proper weirs, was constructed at the lower 

 end of i he completed Lake, and the drainage waters of the Park, from 

 the fall rains, soon filled the Lake to a depth of three feet. Prom 

 careful daily observations of the water level it lias been ascertained 

 that the leakage is so slight as to indicate that the method of puddling 

 adopted is entirely successful. 



Two of the Hart Beck pool* have been completed, with proper ma- 

 sonry dams, which are covered with rock work. The puddling of 



