130 A Milward, Esq., on an Extensive Mud-Slide 



part is covered, and the adjacent streams press against each 

 other. 



These six streams may be considered as nearly independent 

 of one another ; their surface is an inclined plane, varying 

 in its inclination at different points. The part where the 

 flow commenced is usually the steepest ; but in one instance 

 (No. 5) this is not the case ; the slope is there nearly the 

 same throughout. Five out of the six streams present the 

 singular appearance of curved bands, distinguished by being 

 alternately dark and light in colour. These are best seen 

 from a height when the sun is shining brightly upon the 

 mud, and especially if the light fall obliquely. Upon exami- 

 nation, it is found that these curved bands are made apparent 

 by the fact of their being composed alternately of rough and 

 smooth mud. The smooth mud reflects the light more readily 

 than the other, and thus appears of a lighter colour. 



The rough bands are slightly the highest in the example 

 before us, and are most broken up with cracks and crevasses. 

 It will be observed that one of the streams (No. 5) is free 

 from these bands : In the others their breadth varies from 

 about three to six feet. The cracks or crevasses, with 

 which the surface is broken up, are of course very irregular ; 

 but I think they may be classed under two heads, viz., those 

 which are at right angles to the direction of the curves, and 

 those which follow that direction. This remark applies to 

 both the rough and smooth parts, but in the latter there is 

 less confusion, and the crevasses are much further apart. 

 In some places the one class of fissures prevails the most, 

 while in some the other class predominates. Fissures of the 

 first sort are seen prevailing in No. 3 ; those of the second 

 class in No. 5. At the lower extremity of each flow, the 

 mud is much more broken up than elsewhere ; and when the 

 concentric bands become indistinct, the cracks or crevasses 

 are chiefly in that direction. When the mud has been very 

 wet, and the flow steep, it is sometimes broken up by cracks 

 into much more minute divisions ; but this is not always the 

 case, and was observed by me when the wetness seemed 

 confined principally to the surface. Sometimes when the de- 



