508 On the Arborizations of the Son agates. [Sept. 



splendid discovery. My object in this communication is, to convince 

 those who doubt the existence of organic remains in agates from the 

 Sone river, or elsewhere. I therefore beg leave to refer them to the fol- 

 lowing passages in Dr. Ure's Dictionary of Chemistry, published about 

 fifteen years ago, which, in my humble opinion, establishes my point. 



"These curious appearances (meaning the organic remains of plants) were 

 ascribed to deposites of iron or manganese ; but more lately they have been 

 thought to arise from mineralized plants of the cryptogamous class." And 

 again, " Dr. McCulloch has recently detected what Daubenton merely con- 

 jectured, in mocha stone and moss agates, aquatic conferva?, unaltered both in co- 

 lour and form, and also coated with iron oxide. Mosses and lichens have also 

 been observed along with chlorite, in vegetations. An onyx agate, set in a ring, 

 belonging to the Earl of Powis, contains the chrysalis of a moth." I am also of 

 opinion, that the arborescent appearance termed Dendrites in our magnesian 

 limestone, and flag sand-stone, are the remains of mosses and lichens. I have 

 several times tested the substance, but could only detect carbon, which certainly 

 indicates their vegetable origin. I doubt not when they are effectually examined, 

 but they will turn out to be the remains of vegetation." 



The beautiful specimens from the sandstone of Chunar afford an 

 excellent opportunity to those who may wish to set the matter at rest, 

 and I must here remark, that you, as Secretary of the Asiatic Society of 

 Calcutta, might easily accomplish the desired examination. 



I also have another reason for troubling you with this communica- 

 tion. If the appearances in the agates are not the remains of plants, 

 I have in that case asserted a falsehood in my advertisement, published 

 in No. 39 of your Journal. However, with such authorities as the 

 above mentioned, I need not fear again to assert, that the appearances 

 in my agates are the real organic remains of aqueous plants, in a state 

 of preservation not exceeded by any previous discovery, and altogether 

 (as a collection), unique. 



Dr. Ure's Geology affords further proofs to strengthen my original 

 opinion, that the appearances in my agates are truly the remains of 

 plants ; the passage runs thus : 



" If any further evidence of the aqueous origin of chalcedonies and agates were 

 wanted, it has been afforded by Dr. McCulloch in an ingenious paper on the vege- 

 table remains preserved in these siliceous minerals, published in the 3rd volume of 

 the Transactions of the Geological Society. It is there shown that the mode in 

 which the delicate vegetables thus become involved is perfectly simple, and consist- 

 ent with the production of chalcedony. But we must distinguish their real causes, 

 from pseudo specimens of black arborizations, produced by the oxides of manganese 

 and iron, or by chlorite. 



" When real confervse are present, the vegetable form is so perfectly preserved 

 that the plant seems to float freely as if in its liquid element. Even the green often 

 retains its lively hue. 



