THE SILURO-DEVONIAN BOUNDARY QUESTION 473 



the New York and other sections of America where the Siluro-Devonian boundary 

 should be drawn are of three kinds, namely : 



(1) Matters of fact, 



(2) Matters of interpretation. 



(3) Matters of usage. 



(1) The paleontologic facts regarding the resemblance of the Lower Helderberg 

 faunas to Devonian faunas have been thoroughly presented. The facts regarding 

 the resemblance of the Chapman fauna to the standard Tilestone (Silurian) fauna 

 of Europe have been announced, but have not been fully described or illustrated, 

 and therefore are not open for general discussion. * 



(2) The questions of interpretation are dependent on knowledge of the facts, and 

 while there is difference of opinion at the present time, the author believes this is 

 due chiefly to comparative ignorance on the part of all concerning the Upper Lud- 

 low and Tilestone faunas of Europe and their supposed equivalents in America. 

 Until the facts can be brought to the knowledge of all parties interested, discus- 

 sion is not likely to result in correct conclusions. 



(3) Matters of usage (namely, nomenclature and classification) are dominated by 

 the fundamental principle of priority. The first scientifically defined name or 

 classification is entitled to take precedence of all new names and classifications 

 until the old one can be shown to be wrong. Established usage in names and 

 classifications is assumed to be correct until its error is scientifically demonstrated. 

 The burden of proof is with those who criticise. New names are not entitled to a 

 place in science unless they are names for new facts. A geological formation be- 

 longs in the generic group of formations in which, by common usage, it has been 

 included until sufficient reason can be shown for excluding it. 



In consideration of these points, the author urges geologists to refrain from 

 changing established usage regarding the position of the Siluro-Devonian boundary 

 in American rocks until the facts regarding the relationship of the newly discov- 

 ered Chapman fauna to the Tilestone fauna of Europe can be properly presented 

 to paleontologists for their judgment. 



The following paper was read by the author : 



KNOYDART FORMATION OF NOVA SCOTIA 

 BY H. M, AMI 



Remarks were made on the paper by H. S. Williams, N. S. Shaler, 

 and the author. The paper is printed as pages 301-312 of this volume. 



In the absence of the author, the following paper was read b}^ title : 



AGE OF THE COALS AT TIPTON, BLAIR COUNTY,, PENNSYLVANIA* 



BY DAVID WHITE 



The Tipton Run coal mines of Blair county, Pennsylvania, are located at the 

 forks of one of the deep V-shaped ravines heading westward against the Allegheny 

 escarpment about half way between Tyrone and Altoona. The escarpment in this 

 region consists, according to the measurements of Franklin Piatt, t of 2,560 feet of 



*The author of tliis paper does not approve of the rule of non-capitalization of species names 

 when derived from proper names, adopted by the Society. — Ed. 

 t Second Geol. Survey of Pennsylvania, Report I, Blair county, 1881, pp. 7-29. 



