306 



Canadian Record of Science. 



formation. Fortunately, the occuri'ence of a similar fonii 

 in the Chazy of Ho^'s ^ck had been previously ascer- 

 tained 80 that this fact, coupled with the one that the 

 almost perfectly horizontal wtratu on the Quebec side of the 

 Ottawa, were truly Chazy, and characterised by the pre- 

 valence of such types as Orthis imperator (Billings), and a 

 Khynchonella not distinguishable from the B. plena of Hall 

 — which measures extended across the river to the Ontario 

 side, beneath the watera of the lake and rapids, without a 

 fault or dislocation in well-nigh horizontal beds — make it 

 beyond doubt that these rocks at Britannia are truly Chazy. 

 From these two instances, it follows that the occurrence 

 of Scolithus remains does not necessarily indicate the exist- 

 ence of Potsdam rocks, but that the beds may possin-ly be 

 newer or higher up in the series. These cases also indicate 

 the necessity of obtaining collateral evidence of every 

 nature, whether palseontological or stratigraphical, in oi-der 

 to ascertain with any degree of accuracy the precise geo- 

 logical horizon of strata. 



Ifi 



j 



The Rhythm and Innervation of the Heart op 



THE Sea-Turtle.=* 



By T. Wesley Mili^, MA., M.D., L.R.C.P.,"'.En... 



Professor of Physiology, M'Gill University, Montreal. 



The present paper is intended in part as a continuation 

 of a shorter one which appeared in Nos. 4, 5, 6, of vol. v. 

 of the Journal of Physiology on the same subject ; but more 

 especially as^ continuation of my work on Chelonian heart 

 physiology in general. So I'ar as 1 know there does not 

 exist in physiology a systematic comparison of the resem- 

 blances and diiferences of any one family or genus. I pro- 

 pose therefore to do for the Chelonians in physiology, to 

 some extent at least, what has been done for them in mor- 

 phology. 



It has hitherto been believed that animals resembling 



* This paper has also very recently appeared in the Jour, of 

 AnaL and Phys., Edinburgh. 



