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schistus found at Reykum, one of the great spouting hot springs in 

 Iceland. The singularity of this substance is, that a great part of it 

 consists of leaves, (evidently those of the alder,) interposed between 

 the different lamellae. These leaves appeared to be in the state of 

 charcoal ; but on more close examination, no doubt remained of their 

 still retaining a certain portion of some of the other principles of the 

 original vegetable, such as extract and resin. This, in fact, is the 

 result of an extensive chemical process, from which we learn that the 

 schistus, taken collectively, yields, besides silicia, alumina, and oxide 

 of iron, a certain proportion of water and of vegetable matter, and 

 that it evidently belongs to the family of argillaceous schistus. 



The above process may be considered as preliminary to that on 

 the Bovey coal, in which the vegetable characters are more obliterated 

 than in the leaves of the schistus. This coal, we are told, bears a 

 great resemblance to a fossil found in Iceland, called Surturbrand ; 

 the strata of both being composed of trunks of trees, which have 

 completely lost their cylindrical form, and are flattened, as if they 

 had been subjected to an immense degree of pressure. On inquiring 

 into this last-mentioned circumstance, our author produces his rea- 

 sons for believing that it is not the effect of the mere pressure of a 

 superincumbent stratum, but also of a certain change in the solidity 

 of the vegetable bodies, and a powerful mechanical action, produced 

 by the contraction of the argillaceous strata in consequence of desic- 

 cation. 



Here follows the analysis of the Bovey coal. The results point 

 out a great resemblance between this substance and that which forms 

 the leaves contained in the Iceland schistus. The only exception is, 

 that the leaves contain some vegetable extract, none of which could 

 be discovered in the coal. Both consist of woody fibre in a state of 

 semicarbonization, impregnated with bitumen and a small portion of 

 resin, perfectly similar to that which is contained in many recent 

 vegetable characters, and is but partially and imperfectly converted 

 into coal ; so, in like manner, some of the other vegetable princi- 

 ples have only suffered a partial change. Next to this woody fibre, 

 resin is thought to be the substance which, in vegetables passing to 

 the fossil state, most powerfully resists any alteration, and which, 

 when this change is at length effected, is more immediately the sub- 

 stance from which bitumen is produced. 



This opinion, that the vegetable extract and resin are the parts of 

 the original vegetables, which retain their nature after other portions 

 of the same have been modified into bitumen, is corroborated by the 

 analysis which here follows, of a singular substance which is found 

 with the Bovey coal. Dr. Milles, who first mentioned this substance, 

 considered it as a loam saturated with petroleum ; but our author, 

 on mere inspection, decided that it is not a loam, but a peculiar bi- 

 tuminous substance. After a description of its external appearances, 

 and some of its relative properties, we come to the analysis ; from 

 which we collect, that this is a peculiar and hitherto unknown sub- 

 stance, which is partly in the state of vegetable resin, and partly in 



