260 Remarks on Rocks accompanying Anthracite. 



*M. Beudant's tertiary class can be only local, confined 

 to the basin of the north of France, and the south of Ena;- 

 land, as it consists of all the strata that lie above the chalk. 

 As there is no chalk in the United States, there can be no 

 tertiary class, and in many other countries, such as Norway, 

 Sweden, &e. I iound a small band of chalk between Mos- 

 cow and the Black sea, in Russia, entirely surrounded by 

 alluvion. Chalk is a very rare rock and cannot possibly 

 be considered as a good foundation for a class. 



REMARK BY THE EDITOR. 



The above communication was received a good while 

 since, and ought to have appeared before — but owing to 

 the editor's ill health it was accidentally postponed. 



Remarks on the rocks accompanying anthracite at Wilkeshar- 

 re and elsezohere, by Pres. Maclure, in a letter to the Editw 

 dated Madrid, Aug. 20, 1822. 



I observe in your Journal a description of the anthracite 

 at Wilkesbarre, Pennsylvania, by Mr. Cist. In describing 

 the accompaning rocks (the most essential part of Geology) 

 he gives a very correct mineralogical description, but that is 

 not sufficient to be comprehended by the European geolo- 

 gist; for all the aggregates, secondary or transition, have 

 pretty much the same mineralogical structure ; but the po- 

 sition and relative situation decides the class and fixes th* 

 nature of the rock. The whole region about Wilkesbarre 

 belongs to the transition class, and all the slate he describes 

 with spots of mica, must be gray wacke slate. Aggregates 

 of large rounded pebbles cemented by quartz, form the 



*M. Beudant mentions the carbonate of iron,accompaBymg; his Gres hou- 

 illier, and confounds it wjth the argillaceous oxide of iron, found in the coal 

 measures of England, out of which the greatest part of the English iron is 

 made. The carbonate of iron rarely, if ever, occurs in* coal measures, but 

 is often found in transition rocks, another presumption that there is some 

 error in supposing that the Carpathian and Appenine mountains consist 

 principally of Gres houillier or coal measures. 



So greatly superior is the field in the United States for the study of geol- 

 ogy, that it is probable when its advantages are generally known it will be 

 visited by geologists, as Greece and Italy are just now by antiquarians. 



