PREHISTORIC ENGINEERING AT LAKE COPAIS. 215 



The middle canal, constructed to receive the waters of the 

 Hyrciniis, traverses the center of the lake and connects near the 

 east end with the south canal. Unlike the north canal it is made 

 wholly by excavation, the earth thrown out forming its banks, 

 and it is nowhere strengthened by masonry. The alluvial depos- 

 its from the stream have n&arly obliterated it in parts, but its 

 course is easily traceable and in some places, especially near the 

 western end, the works exhibit formidable dimensions, showing 

 in cross- section an excavation of more than a hundred metres to 

 the lineal metre. 



The south canal, for the reception of the waters of the Per- 

 messus, Olmeus, and other small streams from Helicon, starts 

 from the southwest end of the lake, and, following the south bank 



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Profile following the Line of the Wells. 



past Tilphusium and Haliartus, rounds the cliffs of Mount 

 Sphingium, a little distance from the shore, and unites probably 

 with the middle canal in the bay of Carditza, The two thus 

 united finally join the north canal in the Bay of Kephalari, and 

 the waters of all three are then conducted in a single channel 

 across the bay and into the several katabothra at its foot. Al- 

 though most of the first part of this canal is gone, parallel em- 

 bankments, more than fifty metres apart, inclosing an excavation, 

 are to be seen in places, occasionally strengthened with stone 

 work. At the junction of the several canals especially, the work 

 has been executed with great care, the dykes being sustained by 

 Cyclopean walls as solid and probably as ancient as those at 

 Mycsene and Tiryns. Although the main waters of the south 

 canal were poured into the middle and finally into the north 

 canal, all along its course part of their volume was deflected 



