Rev. W. Doicnes — A Section near Honiton, Devon. 309 



arenaceous, which are now to be discussed. Both the Eed Marl and 

 the dark-coloured arenaceous beds above them have the same easterly 

 dip of about 5°. 



About a mile to the eastward of the tunnel is a north and south 

 fault, and the tunnel beds are on the downthrow side of it. 



Mr. H. B. Woodward and Mr. Ussher had in the work " Geology 

 of England and Wales," p. 237, by the former, expressed an opinion 

 that the beds E. of the tunnel were Gault, and the present writer 

 approached the subject with a decided predisposition in favour of 

 that view. He did not perhaps attach the weight to their opinion 

 that he ought to have done, for he had somehow arrived at the 

 impression that their opinion was but a conjecture, and did not 

 profess to be more. Nevertheless, he would have much hesitated to 

 call it in question, were it not that a piece of entirely new evidence 

 was presented to him. 



In the course of correspondence with the railway officials, he was 

 informed that at the Engineer's office of the Kailway Company there 

 was a detailed diagram of the tunnel on a large scale. He went to 

 see it, and was brought face to face with a dilemma. Either the 

 black beds were Bkastic, or the diagram was wrong. 



Could the latter be wrong? The unknown engineer who con- 

 structed it had had exceptional facilities for accuracy. Shafts had 

 been sunk at frequent intervals, and the position, thickness, character, 

 and colour of every bed was given with great exactness. Many 

 thousands of pounds had depended upon the general accuracy of the 

 section, and though the uppermost beds did not affect the tunnelling, 

 it was but reasonable to suppose that they also would be correctly 

 given. And in them was represented an unconformity exactly like 

 that which exists between the Trias and the Greensand in all the 

 country round about, the Trias (or Bhastic) dipping eastward, the 

 Greensand above it being horizontal. 



A great unconformity in the midst of the Cretaceous series was 

 not to be thought of. If then the diagram was right, the lower beds 

 could be nothing else but Bhsetic. And such the present writer con- 

 sidered them to be until, after a persevering search for fossil evidence, 

 he at last found it ; but lo ! the fossils were Cretaceous ! 



They were : — 



Jnoceramus concentricus (Park.) (abundant). 

 Tornatella [Aclceon) affinis (Sow.) 

 Pecten quadricoslatus (Sow.) 

 Modiola. 



The above occurred in a black marly clay bed about six feet thick, 

 which comes in the middle of the series. 



The diagram, which — tested by the exposed beds at the base — 

 must be accurate in the main, is certainly inaccurate as regards the 

 uppermost beds. As befoi'e remarked, they did not affect the tunnel- 

 ling, and were perhaps carelessly added. Perhaps the designer was 

 in part inspired by the analogy of the surrounding country, with 

 whose geology he was presumably to some extent acquainted. But 

 as his very name is unknown, and he cannot answer for himself, it 

 is useless to discuss his responsibility for the error. 



Tellina. 



Exogyra. 



Pectuncidus. 



