206 Miscellanies. 



necticut, by the fact, that the points of the crescents in that State were 

 all turned in a generally southwest direction, the dip of the strata being 

 northeasterly ; while on the contrary in New Jersey, the opposite 

 direction was observed both in the dip and the points of the crescents. 

 In the abstract referred to, desiring to make the matter as condensed 

 as possible, consistently with clearness, I left out the above allusion to 

 Dr. Percival's report, and the fact, (well known to all acquainted with 

 New England geology,) that Dr. Percival was the original observer of 

 this important feature in our trap system, and confined the report sim- 

 ply to a concise statement of the outlines of the theory proposed, to ac- 

 count for the form observed, taking the fact and the original observa- 

 tion to be well known. I have been informed since the appearance of 

 this abstract, that it wears a coloring of injustice to Dr. Percival, as the 

 original observer of the facts, and their most acute and laborious ex- 

 pounder — since no reference was made to him in the report alluded to. 

 Nothing could have been farther from my thoughts and intentions, than 

 any shadow of injustice to Dr. Percival ; but I freely acknowledge, 

 that on a second perusal of the discussion in question, I can see that it 

 would have been better to have made the allusion to Dr. Percival's dis- 

 covery, contained in the first part of this note. 



Meantime I would say, that it is a subject of much regret with all 

 who are interested in the question, that Dr. Percival has not given us 

 his theoretical and practical views on this subject, in a shape more en- 

 during and extended, than casual conversation with his scientific friends, 

 and verbal communications to the Connecticut Academy of Arts and 

 Sciences.* In his very accurate Report already alluded to, Dr. Percival 

 has felt obliged to confine himself almost entirely to the facts observed, 

 and has dealt very sparingly in those general conclusions which might 

 very legitimately be drawn from them, and which he is so able to give. 

 It is our intention to insert in an early number of this Journal, a re- 

 view of Dr. Percival's Report, and to accompany it by the map of the 

 district examined, from which geologists can form a better notion of the 

 subject of the present note. B. Silliman, Jr. 



Yale College Laboratory, New Haven, Dec. 25, 1843. 



2. Method of scjmrating the Oxides of Cerium and Bidymium ;t by 

 L. L. Bonaparte. :j: — I had been for some time occupied with the study 

 of several metallic valerianates,§ especially that of the oxide of cerium, 



* The earliest of which was communicated to this society, Dec. 25, 1834. 



t From 6iSv\xos, twin. 



t Translated from PoggendorfFs Annalen, Vol. lix, p. 623. The original ap- 

 peared in the Comptes Rendus, T. 16, p. 1008. 



§ Valerianic acid is obtained from the roots of Valeriana officinalis. It forms a 

 large and well characterized class of salts with metallic oxides. — Eds. 



