90 Correspondence. 



off the coast of Cork, etc., all of whicli would be (according to the 

 charts), if the land vas elevated 1000 feet, ''isolated rocky pillars 

 on hills," and yet at the present day they are being formed by Marine 

 action. 



G. Henry Kinahan. 



FAULTS IN THE DRIFT AND "TRAIL." 

 To the Editor of the Geological Magazine. 



Dear Sir, — Mr. S. V. Wood, jun., in your last number, questions 

 the correctness of an observation made by me in the pit at the east 

 end of Chillesford Church. He says, "The capping of Boulder-clay, 

 which rests on the Chillesford beds at Chillesford, and which Mr. 

 Fisher, in his paper read before the Geological Society, brought into 

 his evidence of ' trail,' I believe is nothing but an oblique throw of 

 the Upper Drift on to the Chillesford beds;" and his reason for this 

 belief is, because " in a pit only a furlong and a half north of this 

 section, there occurs one of the junction of the Upper and Middle 

 Drift," showing signs of disturbance. 



Such proximity of the Boulder-clay, in situ, would seem to be a 

 requisite condition for the presence of trail derived from it, but I 

 entirely deny that its being there in a disturbed state proves my ex- 

 planation of its appearance at this spot to be wrong. The trail of 

 Boulder-clay here lies in a dish, or trough, eroded out of perfectly 

 horizontally bedded Chillesford clay. The trail is five feet thick in 

 the centre, and thins out to nothing at its edges. The Chillesford 

 beds occupy a thickness of nine feet beneath it. I saw no indications 

 whatever of this small bit of Boulder-clay being let in by a fault ; 

 and I am not inexperienced in faulted clays and sands, knowing 

 well all the Weymouth, Bridport, and Purbeck districts. 



In reference to the subject of what I have called " trail," I take 

 this opportunity of mentioning a fact, which I omitted to notice 

 in my paper before the Society. It is, that I have in several instances 

 observed in the New Forest, trail containing fossil shells derived 

 from neighbouring fossil beds. Yet the out-crop of these fossil beds 

 is not discoverable by any shells in the warp. They are either 

 entirely dissolved or else converted into selenite. This shows 

 that the agency, which transported the trail, acted to a depth, 

 removed from the effects of ordinary atmospheric causes. 



As regards faults in the Drift, there seems much difficulty in 

 rightly distinguishing among these beds between true faults, arising 

 from disturbance at a subsequent geological period, and the dis- 

 turbances of deposition simulating faults, such as abound in the 

 Norfolk cliffs. Erosion has often laid beds side by side, in a way 

 which looks like faulting, and though unwilling to differ from Mr. 

 Wood, who has so extensive an acquaintance with these deposits, I 

 must confess that I suspect the instance at Bulchamp to be one of 

 that character, because sand occurs beneath the Boulder-clay, seem- 

 ingly continuous with that against which it abuts. It is unusual to 

 meet with any true fault which does not alter the relative levels of 



