Floor of the English Channel. 



63 



As the description and photographs of this chalk-pebble seemed 

 to me to agree much more closely with the Chalk Rock tlian the 

 Melbourn Rock, and as Mr. Worth had not ventured to refer the 



Map showing the spots, marked by crosses, where chalk-pebbles were found. 

 The lines in the Channel are the contours of 40, 45, and 50 fathoms. 



other specimens to any particular horizon, I asked him if he would 

 allow me to examine the slides, and whether he could send me some 

 of the other pebbles which had not yet been sliced. In response to 



