176 Bibliography. 



and Reary, to which I have referred, and immediately recognized the 

 deposit of Blyton Car to be analogous. Indeed, it is remarkable how 

 closely the two descriptions coincide ; and it will be observed, that in 

 both these cases, as well as in that from the United States, the pow- 

 der was found under peat, and resisted the action of acids and of heat. 

 He shortly afterwards procured a fresh supply from Lincolnshire, and 

 submitted it to several friends ; among others he requested me to ex- 

 amine it closely, and communicate the result. The little acquaintance 

 I had with the obscure, neglected, but pre-eminently beautiful and ex- 

 traordinary tribe of the Confervcd, showed me, on the first inspection 

 of the powder, the high probability of its connexion with them ; and 

 a reference to some specimens in my own herbarium, and to magnified 

 figures of others in the works of Greville, Sowerby, &c., soon con- 

 vinced me that it was indeed the accumulated remains of myriads of 

 these minute aquatic plants, purified by the decomposition of all 

 their original vegetable matter, and efiectually secured from contact 

 with other impurities, by the superincumbent peat." 



The article is concluded by an interesting account of the character 

 and habits of the minute Confervas. The specimens described and 

 figured by Mr. Bowman, are species of Diatoma, or allied genei-a. — 

 It has been somewhere remarked, or conjectured, that these deposits 

 are perhaps confined to the region of primitive rocks, although it is 

 not easy to conceive any relation or connexion between these bodies 

 and the nature of the soil or rock where they are accumulated ; and 

 the manner of their occurrence in this case, and indeed on the Euro- 

 pean continent generally, contradicts that supposition.* 



11. Chemical composition of cellular and woody tissue in plants. — 

 That most accomplished vegetable anatomist, Mohl, of Tubingen, 

 has the merit of having satisfactorily ascertained that what is called 

 woody tissue is not simple and homogeneous, but consists of elemen- 

 tary membrane, or cells, and a thickening or encrusting matter that 

 possesses difl"erent properties. The subject has recently been taken 

 up in France by M. Payen, whose memoir, said to be a beautiful spe- 

 cimen of chemico-physiological investigation, was read before the 

 Academy of Sciences in December, 1838, and January, 1839, An 

 abstract of this memoir, and the report of M. Dumas on the subject, 

 are published in the Annales des Sciences Nattirelles, for January, 



* This silicious deposit has been found under nearly every peat bog in this coun- 

 try which has 3'et been examined. Numerous specimens from various parts of this 

 State (Conn.) have been brought to us. When it is calcined and washed it forms a 

 very good polishing powder for metals; and is now, under various feigned names, ex- 

 tensively used for this purpose. — Eds. 



