158 E. M. Kindle — Origin of "Batrachioides the Antiquor ". 



III. — An Inquiry into the Origin of '■^ Batsachioides the 



Antiquor" of the Lockport Dolomite of New York.' 



By E. M. Kindle. 



(PLATES VIII AND IX.) 



rilHE physical history of sedimentary rocks is written in characters 



JL which sometimes baffle the skill of geologists to interpret. This 



may be because geologists are prone to devote too little time to the 



study of roc-ks in the making, and too much to the finished products 



of sedimentation. It is well to remember that the most unpromising 



pool or bit of lake shore may hold the key to the most perplexing 



of these hieroglyphics. 



A brief review of the history of the various attempts to explain 

 certain curious impressions found on the Niagara dol6mites of 

 "Western New York will illustrate the need of closer observation and 

 study of some of the phenomena of our ponds and lakes resulting from 

 the interaction of wind and water. 



The highest beds of the Lockport Dolomite which are exposed in 

 the Niagara Falls region have been cut through by the Erie Canal 

 near Pendleton, N.Y. The rock here is a thin-bedded, black or 

 steel-grey dolomite with numerous thin films of black shale separating 

 successive laminae in some of the beds. Some of these beds show 

 gently concave plates of limestone which have the surface completely 

 covered by shallow contiguous pits (PI. VIII, Eig. 1). These curious 

 impressions are usually about 1 inch in width and have a depth 

 of from i to I in. They are remarkably uniform in character, as 

 shown in the Figure. Well-developed ripple-marks with an amplitude 

 of 1| inches appear on the surface of closely associated beds.^ 



Professor James Hall,* who appeal's to have been the first to observe 

 these impressions, ascribed them to the action of inorganic agencies 

 akin to those which produce concretionary structures. 



In 1850 Professor Benjamin Silliman brought these curious 

 structures to the notice of the American Association for the Advance- 

 ment of Science* and attributed their origin to the agency of great 

 numbers of gregarious fishes. He stated that excavations of similar 

 character and appearance are now made by tadpoles in shallow pools. 

 The eminent naturalist Alexander Agassiz* was inclined, however, 

 to doubt the ability of tadpoles to produce the regular shallow pits 

 on mud which Silliman and Hitchcock ascribed to them. A few 

 years later Professor Edward Hitchcock referred to the Lockport 

 Limestone impressions in connexion with the discussion of very similar 

 markings on the Triassic sandstones at South Hadley, Massachusetts. 

 Professor Hitchcock's remarks bearing upon the kinship in origin of 

 tadpole nests and the impressions on the Lockport Limestone are 

 as follows : " I had been led to doubt the tadpole origin of the South 

 Hadley and New York specimens, by the fact that in many cases the 

 cavities were arranged in lines, and sometimes too it was clear that 



' Published with the permission of the Director of the Geological Survey of 

 Canada. 



'"■ Folio U.S. Geol. Surv. No. 150, pi. xxv. 



^ Geol. New York, 1843, pt. iv, pp. 92-3, fig. 29. 



* Proc. Amer. Assoc. Adv. Sci., vol. iv, pp. 10-12, 1850. " Ibid., p. 12. 



