182 CORRESPONDENCE OF RAY. 



inch, and as thin as a groat, and so proportionably up to 

 the largest, covered with a superficies as thin, and exactly 

 of the colour of silver foil: and where the sea- water 

 washeth them, and they are exposed to the sun and wind 

 when the tide is gone, are tarnished, and appear of a gold 

 purple, blue and red, as anything on which silver foil is 

 laid, when exposed to the sun, wind, and weather, will 

 do in a considerable time. These have the same spiral 

 figures, and as regular as the other serpent stones, and, 

 with a knife being taken off, leave the impressions on 

 both sides of the slate. In such rocks of slate, but much 

 harder, I found (and employed men with tools to dig 

 them out) some of those stones of another kind, thick in 

 proportion to then 1 breadth, from an inch to twenty-eight 

 inches broad ; and the last broadest one was at the great 

 end (on which some authors have fabulously reported 

 the head to grow) six inches thick, all of them covered 

 over with a white scale, which may be taken off, one 

 coat under another, as pearls, or the shells of some fishes. 

 I saw some impression of others near as big as the fore 

 wheel of a chariot. I could not get one of those large 

 ones whole, but brought it home in parts, and have pro- 

 mised a good reward to the labourers I employed if they 

 dig out and send me a whole one, which will be a rare 

 sight, the magnitude, colour, and figure considered. I 

 found other stones something resembling a nautilus, but 

 so much differing from those we know, that I am confident 

 they were never shell-fishes. 



Bradfield, March 27, 1685. 



