BY E. C. ANDREWS. 



811 



way backwards, leaving a deep trench and basins in its wake. 

 Especially does this observation throw light on Alpine lake and 

 sound basin-formation by ice-floods. 



z> c 



— Lo//c/TaD//v/7L s£rcr/or/ /7/y 



S£Cr/OMfOO — 



■j-£cr/o/vcc 



S£Cr/0/\fS3 



Fig. 7. — Plan and section of a peculiar series of basins formed 

 in hard clay, during a severe storm at Bouralong. The figure 

 throws considerable light on the formation of cirques, lake-basins 

 and canon-contours. Dra\Ying by H. Hoggan. 



(b) M u d d 3^ Creek, Sydney. — This watercourse has a 

 run of some two miles above the basin-form now to be described. 

 Dnrinor the " DandenonQ- Storm" in 1876, the creek carved out 

 an amphitheatrically-headed basin some 20 feet below the local 

 baselevel. The basin remained for some 20 3'ears, when 

 successive flood-action had succeeded in aggrading it. 



(c) H i 1 1 g r o V e . — During the severe flood which visited New^ 

 England in 1893, an angular block of granite, some 40 tons in 

 weight, lying in the bed of a small watercourse, was carried two 

 chains downstream by a heavy rush of water. Hosts of boulders, 

 several hundreds of pounds in weight individually, were carried 

 for great distances downstream. Succeeding floods have been 



