Fig. 10 is a plan of the reservoir, with a cross-section of the excavation and embankment. On the lower side the original ground line was cut down in steps, and all loose earth, roots, etc., were carefully removed. The floor of the reservoir was chiefly sillar conglomerate, a hard material that required a considerable amount of blasting for its removal. The embankments were formed in 10-cm. layers of sillar and conglomerate broken into small fragments and then rolled with 3-ton sectional rollers drawn by teams of 4 and 6 mules, which assisted in disintegrating the mass thoroughly, and produced by constant wetting a homogeneous and compact clay. The excavation and embankment were left so that 15 cm. of trimming could be done at a later date, immediately prior to the lining of the reservoir. The excavated material amounted to about 34,000 cu. m., and, of this quantity, 31,500 cu. m. were used to form the embankment; the remainder was taken to a spoil bank immediately adjoining, the black earth stripping being separated and reserved for covering the reservoir, etc. The contract prices for the excavated material placed in the embankment were: Pesos per cubic meter Class 1.--Material which could be removed by plows and scrapers 0.60 Class 2.--This consisted chiefly of "sillar" 1.09 Class 3.--Limestone conglomerate (requiring blasting) 1.65 The prices (for the same classification) for material taken to the spoil bank, were 0.40, 0.80, and 1.40 pesos, respectively. Of the material taken out, 15% came under No. 1 classification, 80% under No. 2, and 5% under No. 3. The excavation was begun at the end of May, 1907, and completed in January, 1908, by Scott and Lee, the contractors. The embankments were then allowed to stand until the beginning of July, 1908, to permit the whole to become thoroughly settled and consolidated prior to beginning the lining. In July the work of trimming the embankments and excavating for the foundations of the reservoir columns was commenced, under the Company's own administration, which completed the entire work. [Illustration: PLATE VI.--DETAILS OF BEAMS AND COLUMNS FOR SOUTH RESERVOIR.] [Illustration: PLATE VIII, FIG. 1.--DETAILS OF FORMS FOR SOUTH RESERVOIR.] [Illustration: PLATE VIII, FIG. 2.--VIEW OF WESTERN HALF OF SOUTH RESERVOIR, SHOWING FINAL SETTING UP OF DERRICK ON CENTRAL COLUMNS.]