220 Letters of Mr. Brongniart, with remarks. 



It is a very important object for Geology, to ascertain the 

 resemblances and differences which exist between the im- 

 pressions in the different countries of the terrestrial globe. 

 I have been much occupied in this labour, and my son, who 

 is devoted more particularly to botany, than to other branch- 

 es of natural history, has aided me effectually in this work. 

 " The bituminous formation of Westfield, near Middletown, 

 appears to me very different from the formation of coal and 

 anthracite of Wilkesbarre and Rhode-Island. You also re- 

 mark that this coal (if nevertheless it be true coal) is found 

 only in thin veins, that it is bituminous, fee. This forma- 

 tion appears to me to have the strongest resemblance to that 

 of the bitummous marl slates of the copper mines in the 

 country of Mansfield and Hesse. The presence of copper 

 is not an essential thing, and besides, it may be that pyrites 

 or some other metallic sulphurets accompany this bitumin- 

 ous formation ; what is certain and very remarkable, is, that 

 this bituminous slate is perfectly similar to that of Mansfield 

 and that the impression of a fish, which we find in that which 

 you have sent me, is entirely hke one of the species of fish- 

 es found in the Mansfield slates — it is the PaloBothrissum 

 freislebenense of Mr. Blainville — a species of fish altogeth- 

 er peculiar; and which has been no where found, except 

 in these formations of bituminous slates — often metalliferous, 

 of the mines of Mercury of the Palatinate, and of Musse, 

 near Autun, department of the Saone and Loire. Indeed 

 sir, the resemblance is so striking, so complete, that if it had 

 not been sent by such a person as yourself, I should have 

 feared that it was a rock with the impression of a fish, which 

 had been formerly transmitted from Hessia to America, for 

 some cabinet, and which through inadvertency, had been 

 erroneously labelled. 



" For the purpose of convincing you of these analogies, 

 so re'markable on account of the great distance, and still, so 

 complete, notwithstanding this distance, 1 send you a spe- 

 cimen of the bituminous slate of Mansfield, with the impres- 

 sion of a fish, and a very imperfect, but sufficient piece of 

 those from the environs of Autun. If you are desirous of o 

 greater number of the former specimens, on being made ac- 

 quainted with it, I will procure them for you. You per- 

 ceive sir, how this first and singular specimen has excited 

 my curiosity, and what a pleasure you will do me if you 



