I'he Ohio Naturalist, 



PUBLISHED BY 



The Biological Club of the Ohio Slate Uni'versily, 

 Volume X. MARCH, 1910, No. 



TABLE OF CONTENTS. 



Lamb — Peimsylvanian Lime.^tones of Northwestern Ohio below the Lower 



Kittanning Coal 89 



Jennings— A Supplementary Description of Cerastium arvense Webbii Jennings . . . 136 



PENNSYLVANIAN LIMESTONES OF NORTHEASTERN OHIO 

 BELOW THE LOWER KITTANNING COAL. 



G. F. Lamb. 

 INTRODUCTION 



In the Lower Coal measures of Pennsylvania and Ohio there 

 occur certain beds of Limestone whose outcrop is known to be 

 more or less continuous around the northern, the northwestern, 

 and the western border of the Appalachian coal basin. This is 

 true more particularly of those limestones occurring below the 

 horizon of the Lower Kittanning coal. This coal with its com- 

 panion, the famous Middle Kittanning coal, constitutes a band 

 which, for extent, continuity, importance, and distinctness, is 

 perhaps second to none in the belt of the Lower Coal measures. 

 This band divides the Lower Coal Measure limestones into two 

 groups — those below the Kittanning Coals and those above them. 



The purpose of this paper is a discussion of the Limestones 

 below these well known coals. Accordingly for definiteness and 

 convenience of reference the line is drawn at the base of the Lower 

 Kittanning coal. 



REVIEW OF LITERATURE. 



For our present knowledge of these limestones as they occur 

 in the State of Pennsylvania, we are indebted chiefly to H. D. 

 Rogers, H. Martyn Chance, L C. White, and F. G. Clapp. Rogers 

 in 1858 in his general section of the bituminous coal field of Penn- 

 sylvania (the section beginning in Mercer and ending in Greene 

 County) gives only two limestones below the Lower Kittanning 

 Coal. The lower one of 2 feet thickness he names the Mercer 

 Limestone. [Geol. Penn. Vol. II, Part I, p. 476.] On the next 

 page of the same report he gives another limestone — Mahoning 

 Limestone — as forming the top of the Tionesta Group. On 

 another page he states as follows: 



IlxjI library) 



