156 NEW YORK STATE MUSEUM 



converged southwestward. It is probable, however, that they passed on 

 southward, after the union of some of them, by different thoroughfares. We 

 here come face to face with certain hypotheses with substantial evidence 

 behind them and they may be stated in terms which will permit of their 

 modification after more detailed knowledge is acquired. 



1 1 The probable trunk troughs entering the southern portions of the 

 geosyncline may be indicated thus : 



a The Connecticut Valley trough. The valley of the Connecticut is 

 ancient, probably not differing in origin from the parallel valleys of Lake 

 Champlain and the Hudson as a graben valley or at least outlined by 

 zones of master faulting. Between the crystalline boundaries of this trough 

 at Lake Memphremagog and southward are evidences showing that it was 

 open earlier than the Devonic, as witness the limestones at Littleton, N. H. 

 with species of Dalmanites (D . 1 u n a t u s Lambert) apparently of very 

 late Siluric age. 



At Lake Memphremagog are grits carrying Taonurus which have been 

 identified by Dr Ami with the Esopus grit but the argillites both above and 

 below these grits contain fossils ; a Dalmanites similar to the D . c o x i u s 

 of the Grande Greve limestone, an Orthoceras of distinctive character, with 

 traces of other fossils. While the Taonurus alone can not be taken as a 

 safe guide for identification with the Esopus horizon of New York yet the 

 accessory evidence is confirmatory of an age for these deposits essentially 

 equivalent to the Oriskany. 



Still farther south at the north line of Massachusetts is the well known 

 occurrence of partly metamorphosed Paleozoic fossils at Bernardston, con- 

 tained in a limestone and an overlying quartzite. These fossils, of which I 

 have had opportunity to examine large series, are invariably distorted in the 

 quartzite where they most abound so that any resemblance they may 

 assume is too often a resemblance by distortion and a determination thereof 

 carries a large element of fiction and imagination. I believe, however, that 

 the conclusions reached long since by Whitfield in regard to the age of 

 these rocks, that the limestones with large crinoid columns are Helder- 



