21 



employed to extract the lead, and the work 

 concludes with a copious catalogue of the 

 western minerals, more particularly those 

 which are employed in the arts. 



The Essay on the Geology of the Hudson 

 river and the adjacent regions^ by S. Akerly, 

 which was published in 1820, although ne- 

 cessarily incomplete in its details, yet adds 

 much to the stock of our information on this 

 region. It corrects many of the errors of 

 preceding writers, more particularly those 

 contained in an anonymous essay published 

 in Paris in 1813, under the title of Observa- 

 tions sur les ties et islots qui sont aux embouchures 

 de V Hudson^ &c. A geological section of the 

 rocks from the Navesink highlands on the 

 Atlantic, extending towards the Kaatskill 

 mountains, accompanies the essay. In this 

 section, it will be remembered, is comprised 

 the celebrated localities of magnesian mine- 

 rals, and within a very short space, we have 

 a view of the different formations from the 

 alluvial to the primitive. 



Nearly simultaneous with the preceding 

 work, appeared the valuable treatise of Mr. 

 Hay den of Baltimore, entitled. Geological 

 Essays^ or an inquiry into some of the Geological 



