476 E. B. Medlicott — On Faults in Strata. 



scription of my observations in tlie Garo and Khasia Hills has lately 

 been published (Mem. Geol. Survey India, vol. vii.,pt. 1), and it may 

 be noticed what confirmation the view taken of the Garo section re- 

 ceives from the observations of the same feature in the Khasia district, 

 where many clear sections are exposed, exhibiting continuously the 

 great flexure of the strata from the high level of the plateau to the 

 very base of the range (compare sections on pp. 154 and 193). 



There is another important stratigraphical character affecting indi- 

 rectly, but in a very marked manner, the question of faulting. Most 

 of us receive our first impressions of stratigraphy from diagrams and 

 models, and it need not be argued how tenacious first impressions 

 are. The type thus implanted might be called the sandwich, or the 

 bread and butter type of stratification ; and, however correct it may 

 be for the very small sections in which it is exhibited, it becomes, as 

 generalized by the green mind, a serious misrepresentation of nature. 

 Thus from such surface indications as those given in the figure (see 

 Woodcut), the unchecked bread-and-butter principle would at once 



'^W 



To illustrate ttie case of an assumed fault, -where only a natural boundary (A) exists. 

 (A.B.C. assumed Fault). 



suggest a fault at (A.) the right-hand boundary. If there were any 

 apparently suggestive circumstances, such as an obscure junction, or 

 comparative straightness of the boundary, there would be no escaping 

 the inference, and the full section given would be that represented 

 by the broken lines of the figure (A.B.C.) ; whereas a stricter ex- 

 amination of the evidence might reduce the features to the more 

 natural cast represented by the curved dotted lines. If such a mis- 

 take could occur in this simplest condition of the case, what are not 

 the risks of error when the compression has been very great ? As I 

 have already got into sufficiently hot water in search of examples, 

 I must leave the reader to cater for himself. 



The word system, as applied to features of direction in stratigraphy, 

 will recall pre-eminently to every geologist the illustrious name of 

 De Beaumont. It seems at first sight strange that an important 

 theory — so elaborately worked out, brought forward with the re- 

 quired circumstances of an inductive discovery, steadily maintained 

 by accomplished (although perhaps prejudiced) authorities, with a 

 fair display of accruing verifications (see " Kapport sur les Progres 

 de la Stratigraphie," par M. L, E. de Beaumont. Paris, 1869), — 

 should not have received adequate examination at the hands of some 

 competent critic, by a full and impartial comparison with reliable 



