418 THE CAMBRIAN. Ibull.81. 



relationship where the deposits compared belong to independent basins, or even to 

 the remote sides of the same great receptacle. The most we can hope to establish is 

 a general agreement in time, with possibly a stricter synchronism of the few chief 

 paroxysmal movements which agitated the bed of the ancient ocean. Partially rep- 

 resentative formations are discoverable, but equivalent ones are not to be looked for 

 upon any philosophical view, since the distribution of organic beings is essentially 

 partial or geographical. The life horizons of the globe are no more universal than 

 are its horizons of sedimentation. With these reservations we turn to the degrees of 

 affinity, linking the American'and European Paleozoic groups of fossils. 



As the result of his correlation he concludes: 



(a) The Appalachian Primal series is obviously nearly on the horizon 

 of BarrantiVs Primordial zone and the lowest rocks of Russia aud 

 Scandinavia. 



(b) The Appalachian Auroral strata may possibly be approximately 

 contemporaneous with the Swedish Orthoceratite limestone. The 

 Auroral series includes the Calciferous, Chazy, and Black River groups. 



(c) The Matinal series of the Trenton and Hudson River groups, 

 from the testimony of the fossils, are represented in Britain by the 

 Llandeilo flags and Caradoc sandstone, or more generally by Sedgwick's 

 Bala or Upper Cambrian group. He also finds a near equivalent in the 

 Orthoceratite limestone of Sweden and Russia and in the Graptolite 

 shales. The authority of Prof. Hall is cited to show the paleontologic 

 similarity of the English and American formations. 



(d) The Levant or Medina group does not appear to be represented in 

 Europe. 



(e) The Surgent and Scalent series, or Clinton and Niagara, are com- 

 pared with the British Wenlock strata. 



(/) The Pre-meridian series or Lower Helderberg. He quotes Mr. 

 Hall as saying that he agrees with Mr. Sharpe and regards the Lower 

 Helderberg strata as representing the Wenlock formation of England, 

 while M. de Verneuil considers them as equivalent to the Ludlow. He 

 then proceeds to correlate the Devonian formations with those of Eu- 

 rope. 



His final conclusion is: 



From all the foregoing facts and statements we arrive at this general inference, 

 that upon both paleontological and physical evidence there is no well marked Silu- 

 rian-Devonian break discernible in the North American basin, no proof of an epoch 

 or general interruption in the life-stream, with wide crust disturbance in the middle 

 Paleozoic ages, such as that which in earlier times, in the morning of the Paleozoic 

 day, at the Cambro-Silurian transition, revolutionized alike the entire extent of the 

 American and European areas, both in their inhabitants and in their physical geog- 

 raphy. 1 



Bigsby. — A most elaborate comparison and correlation between the 

 Paleozoic section of New York and that of Wales was made by Dr. J. 

 J. Bigsby in 1859. He observes that '• both these geological areas ap- 

 pear to have been constructed on the same great comprehensive prin- 

 ciples and nearly of the same material, two most important considera- 



1 Op. cit., p. 186. 



