16 PP. REPORT OF PROGRESS. FONTAINE & WHITE. 



15 feet in thickness, and of these only two are workable 

 over large areas.* 



Flora of The Lower Productive Measures. 

 No special search has been made for plants in this portion 

 of the Coal Strata in West Virginia, and no doubt the list 

 given below might be largely increased by further investi- 

 gations. Two horizons have yielded most of the plants. 

 The lowest is that of the Kittanning Coal Seam near the 

 base of the Series, and the highest is that of the Upper 



Freeport Coal Seam near the top. 

 From the Kittanning Coal we have : 



Lepidostrobus ornatus. L. & H. 

 Lepidophyllum. Spec? 



Neuropteris heteropbylla. Brt. 



N Clarksoni Lesq. 



Lepidodendron Sternbergii. Brt. 



From the Upper Freeport we have : 



JSIeuropteris acutifolia. Brt. I Pecopteris arborescens. Schloth. 



Odontopteris subcuneata. Bmib. I Asteropliyllites rigidus. Brt. 



At both horizons the following plants occur : 



Pecopteris villosa. Brt. 

 Sphenopbyllum Sclilotheiinii. Brt. 



Netiropteris flexuosa. Brt. 



N hirsuta. Lesqx. 



N rarinorvis. Bunb. 



But in Western Pennsylvania Mr. I. F. Mansfield has 

 made a large collection of plants for the Second Geological 

 Survey of Pennsylvania from the Darlington bed, which 

 next overlies the Kittanning bed ; and Prof. Lesqnereux, 

 the fossil botanist of the Survey, has determined from this 

 material the following species, published in Report of Pro- 

 gress Q, White, 1878, p. 55. 



[* Considering the known thickness of the Lower Productive Coal Meas- 

 ures, " barely 260 feet" in the northern counties of West Virginia, — consider- 

 ing that this thickness is wonderfully well preserved in Pennsjdvania for a 

 hundred miles north north-west into the Beaver Valley country, and for more 

 than 150 miles north north-east nearly to the New York State line, — and con- 

 sidering the absence of reliable data for identification in Middle and Southern 

 "SVest Virginia, acknowledged in the text, — one cannot be too cautious in 

 generalizing respecting so extraordinary a thickening of the series in that di- 

 rection. My own surveys on Sandy waters in East Kentucky in 1864, led 

 me to qiaite the opposite view ; for the normal thickness is maintained in that 

 region, if the Hill Sand Rock of Tug Fork be the Mahoning. It will need 

 much "minute examination in the interests of pure science" between the 

 Cheat and the Kanawha before the Mahoning Sandstone can be rightly placed 

 on the latter river; and until that be done it is unsafe to dogmatize about the 

 thickening of the Lower and thinning of the Upper Coal Measures in that 

 direction.— J. P. L.J 



