Messrs. Niles and Wachsmuth on Geolgical Formations, wm 95 
Art. XVI.— Evidence of Two distinct femme Formations in 
the Burlington Limestone; by W. H. Nixes and CHARL LES 
‘W ACHSMUTH." 
Dr. CHARLES A. WuirTE was the first to record any natura) 
division of the Burlington limestone. In the Journal of the Bos- 
ton Society of Natural History, vol. vii, No. 2, Dr. White has 
given a “Section of rocks exposed at Burlington.” He there 
describes eight beds, which he numbers from the lowest upward. 
He refers the first six beds of his section to the Chemung group, 
and beds “No.7” and “No. 8” to the Burlington limestone. 
In vol. ix of the Proceedings Bost. Soc. Nat. Hist., and in 
of the Journal of the same society, Dr. White describes certain 
species of fossils from the Burlington ro¢ks; and although he 
gives the beds or divisions in which the s ecies occur, yet no- 
where does he claim that the Burlington limestone comprises 
more than one geological formation. 
r own observations have led us to regard these two divis- 
limestone, and the upper division, the Upper Burlington lime- 
stone. ‘The reasons for ranking these divisions as distinct 
formations are as follo 
The Burlington limestones are eminently crinoidal “in their 
composition, as well as in their better preserved fossils. Whil 
fragments of th <a Rigor orm an important feature in the 
Teater mass of ocks, there are, —— se, some strata of 
* While making a special study of a hago! of Crinoids, the Actinocrinide, the 
— of which were to have published in the Illustrated Catalogue of the- ‘Museum: 
of Comparative carrie it became achaanry spend considerable time at Bur- 
ington, Iowa, for th hae of studying the ee and valuable collections of Mr. 
Charles Wedanalls; Rey. W. H. eae and Dr. Otto Thieme. From the pub- - 
lished observations of Dr, C. A. W and from some notes made by Mr. Wachs- 
th, Ih 
a an in imate acquaintance with the species, and a series of most ca mee 
tions. Accordingly, with the ahead of Pro Agassiz, rE sesocited myiell with 
Mr. Wachsmuth, for a careful examination and comparison of all the specimens in. 
the three collect: ections, for the identification of the species, and for the determination of 
i ublishing, in e scientific 
freque sth seh ir occurrence. ye 
