ABSTRACTS OF PAPERS 199 



species was first described from Ireland more than half a century ago, but the 

 exact age of the beds containing it there has never been definitely determined. 

 The fact that the shales in which it occurs at Weymouth are of Lower 

 Cambrian age argues for a similar age for the Irish beds. 



Another problematical organism formed the subject of the next paper, 

 presented by the author and illustrated by specimens. Discussion by 

 Messrs, Chadwick, Ulrich, Moore, and Clarke. 



NATURE OF TAONURUS AND ITS USE IN ESTIMATING GEOLOGIC TIME 



BY J. J. GALLOWAY 



(Abstract) 



Taonurus is regarded as the burrow of a sedentary worm which lived in 

 brackish water on a growing delta. Taonurus caudagalli is a structure which 

 appears in vertical sections of the Esopus grit as horizontal series of crescent- 

 in-creseent forms, in layers about one-fourth inch in thickness, extending 

 horizontally many feet and made by different individuals. Most of the rock 

 is composed of this structure. Taonurus caudagalli appears to have been 

 formed by worms burrowing horizontally in a layer of mud, each burrow 

 being about an eighth of an inch from the last. The burrow next to the one 

 being formed collapsed and formed the crescents. After a fresh layer of mad 

 one-fourth inch thick was laid down the new annual crop of worms worked 

 over that layer, sometimes working over the top of the former layers. If 

 the layers of silt represent annual layers, the 700 feet of Esopus grit, ex- 

 clusive of the marine Schoharie, was deposited in about 34,000 years. 



The characteristics and correlation of the faunas of the Pennsylvanian 

 rocks of north Texas were then described by the author; discussion by 

 E. 0. Ulrieh. 



PENNSYLVANIAN FAUNAS OF NORTH TEXAS AND THEIR CORRELATION 



BY RAYMOND C. MOORE 



(Abstract) 



Recent studies based on large collections of invertebrate fossils from the 

 Pennsylvanian formations of north-central Texas indicate that three main 

 faunal groups may be recognized: (1) that from the Bend, (2) that from 

 the Strawn, Canyon, and lower Cisco, and (3) that from the middle and 

 upper Cisco. While these are broadly related, there are distinguishing features 

 which readily differentiate them. As similar faunal groups may be observed 

 in the Pennsylvanian rocks of neighboring areas, there is furnished a fairly 

 satisfactory basis for paleontologic correlation. However, the Pennsylvanian 

 rocks of the Midcontinent region do not appear to be divisible on the basis of 

 faunal distinctions into very minute, widely traceable units. 



The Bend fauna, found in the strata of the Marble Palls limestone and 

 Smithwick shale, is marked chiefly by an element vvbicb is suggestive of the 



