108 ON ROCK REMAINS IN THE BED OF THE ENGLISH CHANNEL. 



A large majority supported living Hyclrozoa, in addition. The animal 

 growth often showed well-marked limits above an underlying bare 

 portion on which the stone had rested in its bed, evidently undisturbed 

 for a long period of time. Such a position, with the greater part of 

 the stone exposed, was the commonest ; but in places, especially near 

 mid-Channel, on (80), S. 16h° W., 48-9 miles, evidence pointed to the 

 stones resting more openly on one another, with very little fine deposit 

 associated with them. Under the more ordinary conditions, with the 

 exposed stones lying scattered about at intervals of a yard or two, 

 in an even shelly or sandy bed, it is not surprising that the 

 bottom of the Channel has been so widely charted as sand and shell, 

 the lead rarely happening to strike these stones except in places 

 where they are exposed to an abnormal degree. There is much reason 

 to believe that the intervening deposit of shell and sand forms for the 

 most part only a thin covering, and that if this could be penetrated to 

 a depth of not many inches, the true bottom of the Channel over the 

 whole of this area would be revealed as an uninterrupted stony bed. 



(4) General Form. — The stones exhibited every gradation of form, 

 between that of perfectly rounded outline and sharp angulation ; the 

 fact that numerous examples of these two extremes repeatedly occurred 

 in the same sample is sufficient to show that little or no wearing 

 action has taken place in recent times. Frequent instances occur of 

 a sequence of events : (1) complete rounding ; (2) sharp fracture ; (3) 

 secondary rounding ; but the ultimate investment of animal growth 

 afforded constant evidence in such cases of the secondary rounding not 

 being recent. 



(5) Bottom-De'posits. — Thirteen hauls were taken with the conical 

 and 1' 6" dredges, two of them being from positions at eight to nine 

 miles outside the Eddystone, and therefore well inside the point where 

 the stones first appear. I am indebted to Mr. E. A. Todd for his 

 assistance in grading the whole of these samples. The results are given 

 in Table II (p. 117), where the samples are arranged in order of their 

 distance on a S.W., Mag. bearing from the Eddystone. The method 

 of grading is that adopted at the Lowestoft Laboratory for estimating 

 the texture of bottom-deposits in connection with the International 

 Fishery Investigations. The material is separated into eight grades 

 by washing it successively through a series of sieves with circular 

 perforations of 15 mm., 10 mm., 5 mm., 2*5 mm., 1*5 mm., I'O mm., 

 and 0'5 mm., the residue which passes through the 0"5 mm. sieve 

 forming the eighth grade. The exceptionally high proportion of 

 "shell" contained in tliese samples, that is to say, fragments of the 

 shells of MoUusca, fragments of plates and spines of Echinodermata, 



