EARTH FISSURES AND SAND CRA.TERS. 59 



section of the actual base as found ; below is the column of sand through 

 which the water was returned to the bed o o. 



The various appearances presented by these so-called craters, due 

 to their combination in various ways, are well shown in the photograph x 

 Frontispiece and Plates XI to XIII, which are reduced from those taken 

 on the spot by Mr. Pearson of Silchar. The simplest case is shown in the 

 Frontispiece ; here there is a single, nearly round crater, the sloping bank 

 of sand surrounding it is very distinct, and in it to the right of the picture 

 a breach will be noticed ; within this come the steep water- washed sides 

 of the hollow, losing themselves in the nearly flat but slightly concave 

 floor of sand, which has cracked in drying ; in the same plate there are 

 shown some other simple pits, one of which, it will be noticed, is sur- 

 rounded by a very marked rim of sand. It is impossible to look at this 

 photograph and the figures of the round ponds produced by the Cala- 

 brian earthquake of 1783, as given by Lyell in his Principles of Geology, 

 without being struck by their resemblance ; in fact, only fill the hollows 

 at Cachar with water and the two are identical. This filling with water 

 may be due to either of two causes, either the water may not completely 

 drain out of the hollows, or it may do so leaving a more or less water- 

 tight floor on which rain water could collect. The phenomena repre- 

 sented in Plate XI are rather more complicated, two c craters' having run 

 together and produced an irregular hollow. In Plate XII it will be 

 seen that a number of vents have been formed, evidently along a line 

 of fissure, and have more or less coalesced ; while Plate XIII shows 

 no distinct vents ; but the sand and water has been forced out from 

 a continuous open fissure, and this further shows the form of sides 

 which is formed by the sand deposited from the ejected matter, there 

 being only here and there any traces of those appearances produced 

 by the washing down of soil by water, the whole presenting a much 

 smoother and more rounded appearance than is the case in any of 

 the other views. 



1 The vertical cliffs seen in these photographs represent one side of the fissure through 

 which the sand &c, was forced up, the other having sunk ; they are only 1 or 2 feet 

 high. 



( 59 ) 



