Grectham Common, must, I suppose, be 

 of the same kind with those you con- 

 sider'd as chert, though I should rather 

 consider them as flints ; for though they 

 are opake and had nothing of that horny 

 look, when broken, that the flints from 

 the chalky countries have, yet they have 

 more of the glassy texture, and want 

 that appearance of toughness, which the 

 cherts in general have, so that I should 

 not hesitate to call them flints rather than 

 cherts. At the same time, I can easily 

 conceive that our ideas of them may not 

 so far coincide, but that you might well 

 enough look on them as belonging to the 

 cherts. I however met with, amongst 

 the rest, two or three flints that every- 

 body must look on as such, being, when 

 broken, black and horny, and as perfect 

 as the most perfect of the chalk country 

 flints ; they were also roundish like those, 

 and were cover'd with a dark brown 

 coat ; whereas the others had no coat, 

 nor any appearance of ever having had 

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